## 1. Conception of Knowledge


### 1.1 Analysis of Perfect Knowledge



I shall refer to the brand of knowledge Descartes seeks in the
*Meditations*, as 'perfect knowledge' -
a brand he sometimes discusses in connection with the Latin term *scientia*. Famously, he defines perfect knowledge in terms of doubt. While distinguishing perfect knowledge from lesser grades of conviction, he writes:



> 
> I distinguish the two as follows: there is conviction
> [*persuasio*] when there remains some reason which might lead
> us to doubt, but knowledge [*scientia*] is conviction based on
> a reason so strong that it can never be shaken by any stronger reason.
> (24 May 1640 letter to Regius, AT 3:65, CSMK 147)
> 



In the Second Replies, he adds:



> 
> ... I shall now expound for a second time the basis on which
> it seems to me that all human certainty can be founded.
> 
> 
> First of all, as soon as we think that we
> correctly perceive something, we are spontaneously convinced that it
> is true. Now if this conviction is so firm that it is impossible for
> us ever to have any reason for doubting what we are convinced of, then
> there are no further questions for us to ask: we have everything that
> we could reasonably want. ... For the supposition which we are
> making here is of a conviction so firm that it is quite incapable of
> being destroyed; and such a conviction is clearly the same as the most
> perfect certainty. (AT 7:144f, CSM 2:103)
> 
> 
> 



These passages (and others) suggest an account wherein doubt is the
contrast of certainty. As my certainty increases, my doubt decreases;
conversely, as my doubt increases, my certainty decreases. The
requirement that knowledge is to be based in complete, or perfect
certainty, thus amounts to requiring a complete inability to doubt
one's convictions - an utter *indubitability*. This
conception of the relationship between certainty and doubt helps
underwrite Descartes' methodical emphasis on doubt, the
so-called 'method of doubt' (discussed in
 Section 2).



That perfect knowledge requires that it be "impossible for
us ever to have any reason for doubting what we are convinced
of" marks an extraordinarily high standard of justification.
Does Descartes view this as the only standard deserving of 
*knowledge*-talk? Arguably, *no*; yet this is a
difficult question, because he didn't write in English. He
seems to be an epistemic *contextualist*, at least in the
sense of invoking some notion of *cognition*, or 
*knowledge*, in divergent contexts presupposing different 
epistemic standards. We'll see, for example, that he holds
that even the deductive demonstrations of expert geometers may
fall short of the standards needed for perfect knowledge; yet,
the kind of terminology he uses to characterize their epistemic 
achievements is routinely rendered in terms of knowledge-talk, in 
standard English translations of his work.



The certainty/indubitability of interest to Descartes is psychological
in character, though not *merely* psychological - not
simply an inexplicable feeling. It has also a distinctively epistemic
character involving a kind of rational insight. During moments of
certainty, it is as if my perception is guided by "a great
light in the intellect" (Med. 4, AT 7:59, CSM 2:41). This 
rational illumination empowers me to "see utterly clearly
with my mind's eye"; my feelings of certainty are
*grounded* - indeed, "I see a manifest
contradiction" in denying the proposition of which I'm
convinced (Med. 3, AT 7:36, CSM 2:25).



Descartes characterizes these epistemically impressive cognitions
in terms of their being perceived *clearly* and
*distinctly*. The *Meditations* never defines these
terms; indeed, it sometimes uses them in confusing ways (e.g.,
sometimes using *clarity*-talk as a shorthand for the
conjunction of clarity and distinctness). However, in the 
*Principles* Descartes offers the following definitions:



> 
> I call a perception "clear" when it is present and
> accessible to the attentive mind ... I call a perception
> "distinct" if, as well as being clear, it is so sharply
> separated from all other perceptions that it contains within itself
> only what is clear. (*Prin*. 1:45, AT 8a:21f, CSM 1:207f)
> 



Other texts indicate that clarity contrasts with *obscurity*,
and distinctness with *confusedness*. Though having clear and
distinct apprehension is epistemically impressive, we'll see
clear texts indicating that this marks a merely necessary condition
of perfect knowledge, not a sufficient condition.



Should we regard Descartes' account of perfect knowledge as a
version of the *justified true belief* analysis of knowledge
tracing back to Plato? The above texts are among Descartes'
clearest statements concerning perfect knowledge. Yet they raise
questions about the extent to which his account is continuous with
other analyses of knowledge. Prima facie, his characterizations imply
a *justified belief* analysis - or, using language closer
to his own (and where justification is construed in terms of
unshakability), an *unshakable conviction* analysis.
There's no stated requirement that the would-be knower's
conviction is to be *true*, as opposed to being unshakably
*certain*. Is truth, therefore, not a requirement of perfect
knowledge? We'll return to the issue in
 Section 6.4.


### 1.2 Internalism and Justification



One way to divide up theories of justification is in terms of the
internalism-externalism distinction. Very roughly: a theory of
epistemic justification is *internalist* insofar as it requires
that the justifying factors are accessible to the knower's
conscious awareness; it is *externalist* insofar as it does not
impose this requirement.



Descartes holds an internalist account requiring that all justifying
factors take the form of *ideas*. (For a partly externalist 
interpretation of Descartes, see Della Rocca 2005.) Various texts 
imply that ideas are, strictly speaking, the only objects of immediate 
perception or awareness. (More on the directness or immediacy of sense 
perception in 
 Section 9.1.)
 Independent of assumptions about the directness of perception,
Descartes' method of doubt underwrites an assumption with
similar force: for almost the entirety of the *Meditations*,
his meditator-spokesperson - hereafter, the
'meditator' - adopts the methodological assumption
that all his thoughts and experiences are occurring in a dream. This
assumption is tantamount to requiring that justification comes in the
form of ideas, rather than via direct perception of an extramental
world.



An important consequence of this kind of interpretation -
i.e., a traditional representationalist understanding of ideas
- is that rigorous philosophical inquiry must proceed via an
inside-to-out strategy. This strategy is assiduously followed in the
*Meditations*, and it endures as a hallmark of many early
modern epistemologies. Ultimately, all judgments are grounded in an
inspection of the mind's own ideas. Philosophical inquiry
*is*, properly understood, an investigation of ideas. The
methodical strategy of the *Meditations* has the effect of
forcing readers to adopt this mode of inquiry.



In recent years, some commentators have questioned this traditional
way of understanding the mediating role of ideas. Noteworthy is John
Carriero's outstanding commentary on the *Meditations*
(2009), an account providing a serious challenge to traditional
representationalist interpretations (including the kind of 
interpretation often assumed in the present account).


### 1.3 Methodist Approach



How are would-be knowers to proceed in identifying candidates
for perfect knowledge? Distinguish *particularist* and
*methodist* answers to the question. The particularist
is apt to trust our prima facie intuitions regarding particular 
knowledge claims. These intuitions may then be used to help
identify more general epistemic principles. The methodist, by
contrast, is apt to distrust our prima facie intuitions. The
preference is instead to begin with general principles about
proper method. These methodical principles may then be used to
arrive at settled, reflective judgments concerning particular
knowledge claims.



Famously, Descartes is in the methodist camp. Those who haphazardly
"direct their minds down untrodden paths" are sometimes
"lucky enough in their wanderings to hit upon some truth,"
but "it is far better," writes Descartes, "never to
contemplate investigating the truth about any matter than to do so
without a method" (*Rules* 4, AT 10:371, CSM 1:15f). Were
we to rely on our prima facie intuitions, we might accept that the
earth is unmoved, or that ordinary objects (as tables and chairs)
*are* just as they *appear*. Yet, newly emerging
mechanist doctrines of the 17th century imply otherwise. Descartes
thinks such cases underscore the unreliability of our prima facie
intuitions and the need for a method by which to make epistemic
progress.



Descartes' view is not that *all* our pre-reflective
intuitions are mistaken. He concedes that "no sane person has
ever seriously doubted" such particular claims as "that
there really is a world, and that human beings have bodies"
(Synopsis, AT 7:16, CSM 2:11). But such pre-reflective judgments may
be ill-grounded, even when true.



The dialectic of the First Meditation features a confrontation between
particularism and methodism, with methodism emerging the victor. For
example, the meditator (while voicing empiricist sensibilities) puts
forward, as candidates for the foundations of knowledge, such prima
facie obvious claims as "that I am here, sitting by the fire,
wearing a winter dressing-gown, holding this piece of paper in my
hands, and so on" - particular matters "about which
doubt is quite impossible," or so it would seem (AT 7:18, CSM
2:12f). In response (and at each level of the dialectic), Descartes
invokes his own methodical principles to show that the prima facie
obviousness of such particular claims is insufficient to meet the
burden of proof.



Another methodological feature of the *Meditations* is its
first-person, meditative character. Gary Hatfield explains.



> 
> Descartes adopted the strategy of writing his *Meditations* as
> meditations. In other words, he modeled his book in metaphysics and
> the theory of knowledge (or "epistemology") on a form of
> religious writing, that of "meditations" or
> "spiritual exercises" ... In spiritual exercises,
> which were common in Jesuit schools such as the one Descartes attended
> (La Fleche), readers learn to abandon the world of the senses
> and sensuality and to focus on God. ... Because the
> *Meditations* is constructed in the hope that each reader will
> take on the identity of the "I" of the narrative, the
> presumed reader of the text is called "the meditator."
> (2006, 125)
> 


### 1.4 Innate Ideas



Descartes' commitment to innate ideas places him in a
rationalist tradition tracing back to Plato. Knowledge of the nature
of reality derives from ideas of the intellect, not the external
senses. An important part of metaphysical inquiry therefore involves
learning to think with the intellect. Plato's allegory of the
cave portrays this rationalist theme in terms of epistemically
distinct worlds: what the senses reveal is likened to shadowy imagery
on the wall of a poorly lit cave; what the intellect reveals is
likened to a world of fully real beings illuminated by bright
sunshine. The metaphor aptly depicts our epistemic predicament given
Descartes' own doctrines. An important function of his methods
is to help would-be perfect knowers redirect their attention from the
confused imagery of the senses to the luminous world of clear and
distinct ideas of the intellect.



Further comparisons arise with Plato's doctrine of recollection.
In the Fifth Meditation, in connection with the discovery of innate
truths within, the meditator remarks: "on first discovering them
it seems that I am not so much learning something new as remembering
what I knew before" (Med. 5, AT 7:64, CSM 2:44). Elsewhere
Descartes adds, of innate truths: 



> 
> [W]e come to know them by the power of our own native intelligence,
> without any sensory experience. All geometrical truths are of this
> sort - not just the most obvious ones, but all the others,
> however abstruse they may appear. Hence, according to Plato, Socrates
> asks a slave boy about the elements of geometry and thereby makes the
> boy able to dig out certain truths from his own mind which he had not
> previously recognized were there, thus attempting to establish the
> doctrine of reminiscence. Our knowledge of God is of this sort. (May
> 1643 letter To Voetius, AT 8b:166f, CSMK 222f)
> 



The famous "wax" thought experiment of the Second
Meditation is supposed to illustrate (among other things) a procedure
to "dig out" what is innate. The thought experiment
purports to help the meditator achieve a "purely mental
scrutiny," thereby apprehending more easily the innate idea of
body (Med. 2, AT 7:30f, CSM 2:20f). According to Descartes, our minds
come stocked with a variety of intellectual concepts - ideas
whose content is independent of experience. This storehouse includes
ideas in mathematics, logic, and metaphysics. Interestingly, Descartes
holds that even our sensory ideas involve innate content. On his
understanding of the new mechanical physics, bodies have no real
properties resembling our sensory ideas of colors, sounds, tastes, and
the like, thus implying that the content of such ideas draws from the
mind itself. But if even these *sensory* ideas count as innate, 
how then are we to characterize the doctrine of innateness? 
Importantly, the formation of these sensory ideas - unlike
purely intellectual concepts - depends on sensory stimulation.
On one plausible understanding, Descartes' official doctrine
has it that ideas are innate *insofar as* their content derives 
from the nature of the mind alone, as opposed to deriving from sense 
experience (cf. Newman 2006). This characterization allows that both 
intellectual and sensory concepts draw on native resources, though not 
to the same extent.



Though the subject of *rationalism* or *nativism*
in Descartes' epistemology deserves careful attention, the
present article generally focuses on Descartes' efforts to 
achieve perfect knowledge. Relatively little attention is given to
his doctrine of innateness, or, more generally, his ontology of 
thought. (For further discussion of his commitment to innateness, 
see Adams 1975, Jolley 1990, Newman 2006, and Nelson 2007.)


## 2. The Methods: Foundationalism and Doubt



Of his own methodology, Descartes writes:



> 
> Throughout my writings I have made it clear that my method imitates
> that of the architect. When an architect wants to build a house which
> is stable on ground where there is a sandy topsoil over underlying
> rock, or clay, or some other firm base, he begins by digging out a set
> of trenches from which he removes the sand, and anything resting on or
> mixed in with the sand, so that he can lay his foundations on firm
> soil. In the same way, I began by taking everything that was doubtful
> and throwing it out, like sand ... (Replies 7, AT 7:536f, CSM
> 2:366)
> 



The theory whereby items of knowledge are best organized on an analogy
to architecture traces back to ancient Greek thought - to
Aristotle, and to work in geometry. That Descartes' method
effectively pays homage to Aristotle is, of course, a welcome result
for his Aristotelian audience. But Descartes views Aristotle's
foundationalist principles as incomplete, at least when applied to
metaphysical inquiry. His method of doubt is intended to complement
foundationalism. The two methods are supposed to work in cooperation,
as conveyed in the above quotation. Let's consider each
method.


### 2.1 Foundationalism



The central insight of foundationalism is to organize knowledge in the
manner of a well-structured, architectural edifice. Such an edifice
owes its structural integrity to two kinds of features: a firm
*foundation* and a *superstructure* of support beams
firmly anchored to the foundation. A system of justified beliefs might
be organized by two analogous features: a foundation of unshakable
first principles, and a superstructure of further propositions
anchored to the foundation via unshakable inference.



Exemplary of a foundationalist system is Euclid's geometry.
Euclid begins with a foundation of first principles -
definitions, postulates, and axioms or common notions - on
which he then bases a superstructure of further propositions.
Descartes' own designs for metaphysical knowledge are inspired
by Euclid's system:



> 
> Those long chains composed of very simple and easy reasoning,
> which geometers customarily use to arrive at their most difficult
> demonstrations, had given me occasion to suppose that all the things
> which can fall under human knowledge are interconnected in the same
> way. (*Discourse* 2, AT 6:19, CSM 1:120).
> 



It would be misleading to characterize the arguments of the
*Meditations* as unfolding straightforwardly according to
geometric method (cf. Curley 2006, 31). But Descartes maintains
that they *can* be reconstructed as such, and he expressly
does so at the end of the Second Replies - providing a
"geometrical" exposition of some of his central lines
of argument, organized as *definitions*, *postulates*,
*axioms or common notions*, and *propositions* (AT
7:160-70, CSM 2:113-120).



As noted above, the *Meditations* contains a destructive
component that Descartes likens to the architect's preparations
for laying a foundation. Though the component finds no analogue in the
methods of geometers, Descartes appears to hold that it is needed in
metaphysical inquiry. The discovery of Euclid's first principles
(some of them, at any rate) is comparatively unproblematic: such
principles as that *things which are equal to the same thing are
also equal to one another* accord not only with reason, but with
the senses. In contrast, metaphysical inquiry might have first
principles that conflict with the senses:



> 
> The difference is that the primary notions which
> are presupposed for the demonstration of geometrical truths are
> readily accepted by anyone, since they accord with the use of our
> senses. Hence there is no difficulty there, except in the proper
> deduction of the consequences, which can be done even by the less
> attentive, provided they remember what has gone before. ... 
> 
> 
> In metaphysics by contrast there is nothing which causes so much
> effort as making our perception of the primary notions clear and
> distinct. Admittedly, they are by their nature as evident as, or even
> more evident than, the primary notions which the geometers study; but
> they conflict with many preconceived opinions derived from the senses
> which we have got into the habit of holding from our earliest years,
> and so only those who really concentrate and meditate and withdraw
> their minds from corporeal things, so far as possible, will achieve
> perfect knowledge of them.
> 
>  (Replies 2, AT 7:156f, CSM 2:111)
> 



Among Descartes' persistent themes is that such preconceived
opinions can obscure our mental vision of innate principles:
where there are disputes about first principles, it is not
"because one man's faculty of knowledge extends more
widely than another's, but because the common notions are in
conflict with the preconceived opinions of some people who, as a
result, cannot easily grasp them"; whereas, "we cannot
fail to know them [innate common notions] when the occasion for
thinking about them arises, provided that we are not blinded by
preconceived opinions" (*Prin*. 1:49f, AT 8a:24, CSM
1:209). These "preconceived opinions" must be "set
aside," says Descartes, "in order to lay the first
foundations of philosophy" (May 1643 letter to Voetius, AT
8b:37, CSMK 221). Otherwise, we're apt to regard, *as*
first principles, the mistaken (though prima facie obvious) sensory
claims that particularists find attractive. Such mistakes in the
laying of the foundations weaken the entire edifice. Descartes
adds:



> 
> All the mistakes made in the sciences happen, in my view, simply
> because at the beginning we make judgements too hastily, and accept as
> our first principles matters which are obscure and of which we do not
> have a clear and distinct notion. (*Search*, AT 10:526, CSM
> 2:419)
> 



Though foundationalism brilliantly allows for the expansion of
knowledge from first principles, Descartes thinks that a complementary
method is needed to help us discover genuine first principles. As
Hatfield writes, "the problem is not to carry out proofs (which
might well be assented to, given the definitions and axioms), but to
discover the axioms themselves (which are hopelessly obscured by the
prejudices of the senses)" (1986, 71). Descartes therefore
devises the method of doubt for this purpose - a method to help
"set aside" preconceived opinions.



(For examples of non-foundationist interpretations, see Bennett 1990,
Frankfurt 1970, Sosa 1997a, and Della Rocca 2011.)


### 2.2 Method of Doubt



Descartes opens the First Meditation asserting the need "to
demolish everything completely and start again right from the
foundations" (AT 7:17, CSM 2:12). The passage adds:



> 
> Reason now leads me to think that I should hold back my assent from
> opinions which are not completely certain and indubitable just as
> carefully as I do from those which are patently false. So, for the
> purpose of rejecting all my opinions, it will be enough if I find in
> each of them at least some reason for doubt. (AT 7:18, CSM 2:12)
> 



In the architectural analogy, we can think of bulldozers as the
ground-clearing tools of demolition. For knowledge building,
Descartes construes sceptical doubts as the ground-clearing tools of
*epistemic* demolition. Bulldozers undermine literal ground;
doubt undermines epistemic ground. Using sceptical doubts, the
meditator shows how to find "some reason for doubt" in all
his preexisting claims to knowledge.



The ultimate aim of the method is constructive. Unlike "the
sceptics, who doubt only for the sake of doubting," Descartes
aims "to reach certainty - to cast aside the loose earth
and sand so as to come upon rock or clay" (*Discourse* 3,
AT 6:29, CSM 1:125). Bulldozers are typically used for destructive
ends, as are sceptical doubts. Descartes' methodical innovation
is to employ demolition for constructive ends. Where a
bulldozer's force overpowers the ground, its effects are
destructive. Where the ground's firmness resists the
bulldozer's force, the bulldozer might be used constructively
- using it to reveal the ground *as* firm. Descartes thus
uses sceptical doubts to test the firmness of candidates put forward
for the foundations of knowledge.



According to at least one prominent critic, this employment of
sceptical doubt is unnecessary and excessive. Writes Gassendi:



> 
> There is just one point I am not clear about, namely why you did not
> make a simple and brief statement to the effect that you were
> regarding your previous knowledge as uncertain so that you could later
> single out what you found to be true. Why instead did you *consider
> everything as false*, which seems more like adopting a new
> prejudice than relinquishing an old one? This strategy made it
> necessary for you to convince yourself by *imagining a deceiving
> God or some evil demon who tricks us*, whereas it would surely
> have been sufficient to cite the darkness of the human mind or the
> weakness of our nature. (Objs. 5, AT 7:257f, CSM 2:180; italics added)
> 



Here, Gassendi singles out two features of methodical doubt -
its *universal* and *hyperbolic* character. In reply,
Descartes remarks:



> 
> You say that you approve of my project for freeing my mind from
> preconceived opinions; and indeed no one can pretend that such a
> project should not be approved of. But you would have preferred
> me to have carried it out by making a "simple and brief
> statement" - that is, only in a perfunctory fashion. Is
> it really so easy to free ourselves from all the errors which we have
> soaked up since our infancy? Can we really be too careful in carrying
> out a project which everyone agrees should be performed? (Replies 5,
> AT 7:348, CSM 2:241f)
> 



Evidently, Descartes holds that the *universal* and
*hyperbolic* character of methodical doubt is helpful to its
success. Further appeal to the architectural analogy helps elucidate
why.



Consider first the *universal* character of doubt - the
need "to demolish everything completely and start again right
from the foundations." The point is not merely to apply doubt to
*all* candidates for perfect knowledge, but to apply doubt
*collectively*. Descartes offers the following analogy:



> 
> Suppose [a person] had a basket full of apples and, being worried that
> some of the apples were rotten, wanted to take out the rotten ones to
> prevent the rot spreading. How would he proceed? Would he not begin by
> tipping the whole lot out of the basket? And would not the next step
> be to cast his eye over each apple in turn, and pick up and put back
> in the basket only those he saw to be sound, leaving the others? In
> just the same way, those who have never philosophized correctly have
> various opinions in their minds which they have begun to store up
> since childhood, and which they therefore have reason to believe may
> in many cases be false. They then attempt to separate the false
> beliefs from the others, so as to prevent their contaminating the rest
> and making the whole lot uncertain. Now the best way they can
> accomplish this is to reject all their beliefs together in one go, as
> if they were all uncertain and false. They can then go over each
> belief in turn and re-adopt only those which they recognize to be true
> and indubitable. (Replies 7, AT 7:481, CSM 2:324)
> 



That even one falsehood would be mistakenly treated as a genuine
first principle - say, the belief *that the senses are
reliable*, or *that ancient authorities should be trusted*
- threatens to spread falsehood to other beliefs in the system.
A collective doubt helps avoid such mistakes. It ensures that the
method only approves candidate first principles that are unshakable in
their own right: it rules out that the appearance of unshakability is
owed to logical relations with other principles, themselves not
subjected to doubt.



How is the *hyperbolic* character of methodical doubt supposed
to contribute to the method's success? The architectural analogy
is again helpful. Suppose that an architect is vigilant in employing a
universal/collective doubt. Suppose, further, that she attempts to use
epistemic bulldozers for constructive purposes. A problem nonetheless 
arises. How big a bulldozer is she to use? A light-duty bulldozer
might be unable to distinguish a medium-sized boulder from immovable 
bedrock. In both cases, the ground would *appear* immovable. 
Descartes takes the solution to lie in using not light-duty, but
*heavy-duty* tools of demolition - the bigger the
bulldozer, the better. The lesson is clear for the epistemic builder:
*the more hyperbolic the doubt, the better*.



A potential problem remains. Does not the problem of the
"light-duty bulldozer" repeat itself? No matter how
firm one's ground, might it not be dislodged in the face of
a yet bigger bulldozer? This raises the worry that there might not
*be* unshak*able* ground, as opposed to ground which
is *yet unshaken*. Descartes' goal of utterly
indubit*able* epistemic ground may simply be elusive.



At this juncture, perhaps the architectural analogy breaks down
in a manner that serves Descartes well. For though there is no 
*most*-powerful literal bulldozer, perhaps epistemic
bulldozing is not subject to this limitation. Descartes seems
to think that there *is* a *most*-powerful doubt
- a doubt than which none more hyperbolic can be conceived.
The Evil Genius Doubt (and equivalent doubts) is supposed to
fit the bill. If the method reveals epistemic ground that stands
fast in the face of a doubt *this* hyperbolic, then, as 
Descartes seems to hold, this counts as epistemic bedrock if
anything does.



Hence the importance of the *universal* and *hyperbolic*
character of the method of doubt. Gassendi's suggestion that we
forego methodical doubt in favor of a "simple and brief
statement to the effect that [we're] regarding [our] previous
knowledge as uncertain" misses an important, intended point
of the method.



Descartes' method of doubt has been subject to numerous
objections - some fair, others less so. Rendered in the terms
Descartes himself employs, the method is arguably less flawed than its
reputation. Let us consider some of the common objections. Two such
objections are suggested in a passage from the pragmatist Peirce:



> 
> We cannot begin with complete doubt. We must begin with all the
> prejudices which we actually have when we enter upon the study of
> philosophy. These prejudices are not to be dispelled by a maxim [viz.,
> the maxim that the philosopher "must begin with universal
> doubt"], for they are things which it does not occur to us
> *can* be questioned. Hence this initial skepticism will be a
> mere self-deception, and not real doubt ... A person may, it is
> true, in the course of his studies, find reason to doubt what he began
> by believing; but in that case he doubts because he has a positive
> reason for it, and not on account of the Cartesian maxim. Let us not
> pretend to doubt in philosophy what we do not doubt in our hearts.
> (1955, 228f)
> 



Note, however, that the procedure of the *Meditations* is not
that universal doubt is supposed to flow simply from adherence to a
maxim; to the contrary, the doubt is supposed to flow from careful
attention to positive reasons for doubt - recall the express
resolution to find "at least some reason for doubt" in
one's prior opinions. Descartes introduces sceptical arguments
precisely in acknowledgement that we *need* such reasons:



> 
> I did say that there was some difficulty in expelling from our belief
> everything we have previously accepted. One reason for this is that
> before we can decide to doubt, we need some reason for doubting; and
> that is why in my First Meditation I put forward the principal reasons
> for doubt. (Replies 5, appendix, AT 9a:204, CSM 2:270)
> 



A second objection arises from Peirce's contention
that we should "not pretend to doubt in philosophy
what we do not doubt in our hearts". Descartes
presumably agrees that hyperbolic doubt is not (what Peirce
calls) a "doubt in our hearts" - recall
his concession that "no sane person has ever seriously
doubted" such claims as "that there really is a
world, and that human beings have bodies" 
(AT 7:16, CSM 2:11). Further, Descartes makes clear that
we should not extend hyperbolic doubt to practical
matters:



> 
> I made a very careful distinction between the conduct of life
> and the contemplation of the truth. As far as the conduct of
> life is concerned, I am very far from thinking that we should
> assent only to what is clearly perceived. ... from time
> to time we will have to choose one of many alternatives about
> which we have no knowledge ... (Replies 2, AT 7:149,
> CSM 2:106)
> 



Elsewhere, Descartes illustrates the danger in applying 
hyperbolic doubt to practical contexts, with an example of 
someone who "decided to abstain from all food to the
point of starvation, because he was not certain that it was
not poisoned" - a scenario wherein the person 
"would be rightly regarded as insane" (AT 3:422,
CSMK 189). Such dangers, however, do not arise in
connection with theoretical matters, including those
pursued in the *Meditations*. An essential
component of Descartes' constructive epistemology
is the distinction between matters to which we have
*always given assent, in spite of their being
doubtful*, and matters to which we *cannot but
assent while perceiving them clearly and distinctly*. 
Hyperbolic doubt is supposed to show that our previous
opinions are likely of a piece with the former; yet,
perfect knowledge is built from the latter. The emphasis
on doubt is intended to help counter-balance our "habit
of confidently assenting to" what we regard as 
"highly probable opinions," on the grounds that
such matters seem "much more reasonable to believe
than to deny" (Med. 1, AT 7:15, CSM 2:22). The
meditator thus adopts the attitude of methodical doubt
whereby all candidates for belief are treated *as if*
false: "it will be a good plan to turn my will in
completely the opposite direction and deceive myself, by
pretending for a time that these former opinions are utterly
false and imaginary" (*ibid*.) - a plan
that is carried out precisely by subjecting all matters to
hyperbolic doubt.



A related objection takes the method to require not merely doubt,
but disbelief or dissent. One of Gassendi's objections reads
in this manner. He seems to take Descartes to be urging us, quite
literally, to "consider everything as false," a strategy
which, as he says to Descartes, "made it necessary for you to
convince yourself" of the sceptical hypotheses(Objs. 5, AT 
7:257f, CSM 2:180). Based on Descartes' most careful statements, 
however, his method does not require a dissent from the statements it 
undermines. Rather, the method urges us to "hold back [our] 
assent from opinions which are not completely certain and indubitable 
just as carefully as [we] do from those which are patently false" 
(Med. 1, AT 7:18, CSM 2:12, cf. AT 7:461).



Finally, a common objection has it that the universality of doubt
undermines the method of doubt *itself*, since, for example,
the sceptical hypotheses *themselves* are dubious. Descartes
thinks this mistakes the intended scope of the method: namely, to 
extend doubt universally to *candidates for knowledge*, but
not also to the very tools for founding knowledge. As he concedes: 
"there may be reasons which are strong enough to compel us to 
doubt, even though these reasons are themselves doubtful, and hence
are not to be retained later on" (Replies 7, AT 7:473f, CSM 
2:319).



(For further discussion of Descartes's method of doubt, see
Frankfurt 1970, Garber 1986, Larmore 2014, Newman 2006, Williams 1983,
and Wilson 1978.)


## 3. First Meditation Doubting Arguments


### 3.1 Dreaming Doubts



Historically, there are at least two distinct dream-related doubts.
The one doubt undermines the judgment that I am *presently*
awake - call this the 'Now Dreaming Doubt'. The
other doubt undermines the judgment that I am *ever* awake
(i.e., in the way normally supposed) - call this the
'Always Dreaming Doubt'. A textual case can be made on
behalf of both formulations being raised in the
*Meditations*.



Both doubts appeal to some version of the thesis that the experiences
we take as dreams are (at their best) qualitatively similar to those
we take as waking - call this the 'Similarity
Thesis'. The Similarity Thesis may be formulated in a variety of
strengths. A strong Similarity Thesis might contend that some dreams
seem experientially similar to waking, even on hindsight, subsequent
to waking; a weaker rendering of the thesis might contend merely that
dreams *seem* similar to waking *while* having them, but
not upon waking. Arguably, the sceptical doubt is equally potent on
either rendering. Even so, on the most natural reading the First
Meditation passage seems to suggest the stronger view, with its
reference to "exactly similar thoughts":



> 
> How often, asleep at night, am I convinced of just such familiar
> events - that I am here in my dressing-gown, sitting by the fire
> - when in fact I am lying undressed in bed! Yet at the moment my
> eyes are certainly wide awake when I look at this piece of paper; I
> shake my head and it is not asleep; as I stretch out and feel my hand
> I do so deliberately, and I know what I am doing. All this would not
> happen with such distinctness to someone asleep. Indeed! As if I did
> not remember other occasions when I have been tricked by exactly
> similar thoughts while asleep! (AT 7:19, CSM 2:13)
> 



As for the range of experiences that we can suppose dreams to be 
capable of imitating, Descartes looks to hold that *every*
kind of sensory experience is plausibly reproducible in dreams,
and thereby subject to doubt. He writes: "every sensory 
experience I have ever thought I was having while awake I can
also think of myself as sometimes having while asleep"
(Med. 6, AT 7:77, CSM 2:53).



The Similarity Thesis is sufficient to generate straightaway
the Now Dreaming Doubt. Since I can think of a dream as being 
qualitatively similar to my present experience, then, for all
I know, I am now dreaming. I might *be* awake. But if,
for all I know, I am now dreaming, then I lack perfect knowledge
of any matters whose truth presupposes that I am now awake. The
Now Dreaming Doubt does its epistemic damage so long as it
undermines my reasons for believing I'm awake. And at this
stage of the *Meditations*, Descartes thinks that it does: 
"there are never any sure signs by means of which being
awake can be distinguished from being asleep" (Med. 1, AT
7:19, CSM 2:13).



The Now Dreaming Doubt generates widespread sceptical
consequences. For if I do not perfectly know that I am now
awake, then neither do I know that I'm now "holding 
this piece of paper in my hands," to cite an example 
the First Meditation meditator had supposed to be "quite 
impossible" to doubt. Reflection on the sceptical doubt
changes his mind, and he comes around to the view that, for all
he knows, the sensible objects of his present experience are
mere figments of a vivid dream.



Much ado has been made about whether dreaming arguments are
self-refuting. According to an influential objection, similarity
theses presuppose that we *can* reliably distinguish dreams
and waking - we need first to distinguish them, in order to 
compare them; yet the conclusion of dreaming arguments entails that
we *cannot* reliably distinguish them. Therefore, if the 
conclusion of such an argument is true, then the premise invoking
the Similarity Thesis cannot be.



Some formulations of dreaming arguments are indeed self-refuting
in this way. Of present interest is whether *all*
are - specifically, whether Descartes makes the mistake.
It would appear that he does not, based on a Sixth Meditation
passage summarizing the earlier doubts. There, his formulation 
presupposes simply the truism that we do, in fact, make a
distinction between waking and dreaming (never mind whether
reliably). He states the relevant premise in terms of what we 
*think* of as waking, versus what we *think* of
as dreaming: "every sensory experience I have ever 
*thought* I was having while awake I can also *think*
of myself as sometimes having while asleep" (AT 7:77, CSM
2:53, italics added). This formulation avoids the charge of
self-refutation, for it is compatible with the conclusion that
we cannot reliably distinguish dreams and waking.



Does Descartes also put forward a second dreaming argument, the Always
Dreaming Doubt? There is strong textual evidence to support this (see
Newman 1994), though it is by no means the standard interpretation.
The conclusion of the Always Dreaming Doubt is generated from the very
same Similarity Thesis, together with a further sceptical assumption,
namely: that for all I know, the processes producing what I take as
waking are no more veridical than those producing what I take as
dreams. As the meditator puts it: 



> 
> [E]very sensory experience I have ever thought I was having while
> awake I can also think of myself as sometimes having while asleep; and
> since I do not believe that what I seem to perceive in sleep comes
> from things located outside me, I did not see why I should be any more
> inclined to believe this of what I think I perceive while awake. (Med.
> 6, AT 7:77, CSM 2:53)
> 



The aim of the Always Dreaming Doubt is to undermine not whether
I'm now awake, but whether so-called "sensation" is
produced by external objects even on the assumption that I *am*
now awake. For in the cases of both waking and dreaming, my cognitive
access extends only to the productive *result*, but not the
productive *process*. On what basis, then, do I conclude that
the productive processes are different - with external objects
playing more of a role in waking than in dreaming? For all I know,
both sorts of experience are produced by some subconscious faculty
of my mind. As Descartes has his meditator say:



> 
> [T]here may be some other faculty [of my mind] not yet fully known to
> me, which produces these ideas without any assistance from external
> things; this is, after all, just how I have always thought ideas are
> produced in me when I am dreaming. (Med. 3, AT 7:39, CSM 2:27)
> 



The sceptical consequences of the Always Dreaming Doubt are even
more devastating than those of the Now Dreaming Doubt. If I do not
perfectly know that "normal waking" experience is
produced by external objects, then, for all I know, *all*
of my experiences might be dreams *of a sort*. For all I
know, there might not *be* an external world. My best
evidence of an external world derives from my preconceived opinion
that external world objects produce my waking experiences. Yet the 
Always Dreaming Doubt calls this into question:



> 
> All these considerations are enough to establish that it is not
> reliable judgement but merely some blind impulse that has made me
> believe up till now that there exist things distinct from myself which
> transmit to me ideas or images of themselves through the sense organs
> or in some other way. (Med. 3, AT 7:40, CSM 2:27)
> 



The two dreaming doubts are parasitic on the same Similarity Thesis,
though their sceptical consequences differ. The Now Dreaming Doubt
raises the *universal possibility of delusion*: for any one of
my sensory experiences, it is possible (for all I know) that the
experience is delusive. The Always Dreaming Doubt raises the
*possibility of universal delusion*: it is possible (for all I
know) that all my sensory experiences are delusions (say, from a
God's-eye perspective).


### 3.2 Evil Genius Doubt



Though dreaming doubts do significant demolition work, they are
light-duty bulldozers relative to Descartes' most power
sceptical doubt. What further judgments are left to be undermined?
Immediately after the discussion of dreaming, the meditator
tentatively concludes that the results of empirical disciplines 
"are doubtful" - e.g., "physics, astronomy,
medicine," and the like. Whereas:



> 
> [A]rithmetic, geometry and other subjects of this kind, which deal
> only with the simplest and most general things, regardless of whether
> they really exist in nature or not, contain something certain and
> indubitable. For whether I am awake or asleep, two and three added
> together are five, and a square has no more than four sides. It seems
> impossible that such transparent truths should incur any suspicion of
> being false. (Med. 1, AT 7:20, CSM 2:14)
> 



Early in the Third Meditation, it emerges that even truths this
"simple and straightforward" are subject to hyperbolic
doubt (AT 7:35f, CSM 2:25). And immediately following the above First
Meditation passage, Descartes introduces his most hyperbolic doubt
- the hypothesis of an all-powerful deceiver.



There is variation in the interpretation of the doubt, even
concerning the number of deceivers Descartes means to be citing. 
However, I suggest that there is a very natural reading that provides 
for a unified understanding of a single deceiver hypothesis.



The passage initially introducing a deceiver represents the
meditator as having long believed in a creator who is both
all-powerful and all-good. It seems to follow (so the meditator 
reasons) that a creator with these attributes would not allow its 
creatures to be deceived about the existence of the external world,
nor about such transparent truths as that 2+3=5. But likewise,
neither should a creator with these attributes allow its creatures 
*ever* to be deceived. Yet we *are* sometimes
deceived. Since even occasional deception seems to pose a 
*reductio* on the very existence of an all-powerful,
all-good creator, the implication is that the creator (if there
be one) must be lacking in either power or goodness. Suppose the 
creator is all-powerful but *not* all-good - i.e., an 
"evil genius" of sorts. In that case, it seems we might
be deceived about even the most evident of matters.



Notice that this foregoing understanding allows us to read the 
following two passages as referring to the very same sceptical
scenario - namely, a worry about a deceiver who's all-powerful, but not all-good:



> 
> 
> And yet firmly rooted in my mind is the long-standing opinion that
> there is an omnipotent God who made me the kind of creature that I am.
> How do I know that he has not brought it about that there is no earth,
> no sky, no extended thing, no shape, no size, no place, while at the
> same time ensuring that all these things appear to me to exist just as
> they do now? What is more, since I sometimes believe that others go
> astray in cases where they think they have the most perfect knowledge,
> may I not similarly go wrong every time I add two and three or count
> the sides of a square, or in some even simpler matter, if that is
> imaginable? But perhaps God would not have allowed me to be deceived
> in this way, since he is said to be supremely good. But if it were
> inconsistent with his goodness to have created me such that I am
> deceived all the time, it would seem equally foreign to his goodness
> to allow me to be deceived even occasionally; yet this last assertion
> cannot be made. (AT 7:21, CSM 2:14)
> 
> 
> 
> I will suppose therefore that not God, who is supremely good and the
> source of truth, but rather some malicious demon [*mauvais
> genie*] of the utmost power and cunning has employed all
> his energies in order to deceive me. (AT 7:21, CSM 2:15)
> 
> 
> 



Some commentators take these passages to introduce two separate
deceivers - a deceiving God, on the one hand, and an evil
genius (*mauvais genie*), on the other hand (cf. 
Gouhier 1937, 163). Yet this seems to introduce needless
complication without sufficient textual justification. The
deceptions of both deceivers are said to derive from having
supreme power, while (unlike the true God) lacking in goodness.
And note that Descartes expresses ambivalence as to whether even
to refer to a deceiver as 'God': while invoking
hyperbolic doubt, the Second Meditation references the deceiver
as "a God, or whatever I may call him" (AT 7:24,
CSM 2:16). In any case, a single deceiver hypothesis will
hereafter be assumed, referring to it by its popular designation,
the 'Evil Genius Doubt'.



It is tempting to assume that the Evil Genius Doubt draws its
sceptical force from the "utmost power" attributed to the
deceiver. Clear texts suggest a different reading. Descartes contends
that an equally powerful doubt derives from the supposition that we
are not the creatures of an all-powerful creator. Recall that the
above *reductio* reasoning implies simply that the creator
cannot be both all-powerful and all-good. Suppose, then, that we
give-up the assumption that the creator is all-powerful. The passage
continues - while denying that the doubt is thereby weakened:



> 
> Perhaps there may be some who would prefer to deny the existence of so
> powerful a God rather than believe that everything else is uncertain.
> ... yet since deception and error seem to be imperfections, the
> less powerful they make my original cause, the more likely it is that
> I am so imperfect as to be deceived all the time. (AT 7:21, CSM 2:14)
> 



Descartes makes the same point in a parallel passage of the 
*Principles*:



> 
> [W]e have been told that there is an omnipotent God who created us.
> Now we do not know whether he may have wished to make us beings of the
> sort who are always deceived even in those matters which seem to us
> supremely evident ... We may of course suppose that our existence
> derives not from a supremely powerful God but either from ourselves or
> from some other source; but in that case, the less powerful we make
> the author of our coming into being, the more likely it will be that
> we are so imperfect as to be deceived all the time. (*Prin*.
> 1:5, AT 8a:6, CSM 1:194)
> 



Descartes' official position is that the Evil Genius Doubt is
merely one among multiple hypotheses that can motivate the more
general hyperbolic doubt. (See Cunning 2014, 68ff, and Hatfield 2006,
126, for variations on this theme.) Fundamentally, the more general
doubt is about our *cognitive nature*, that is, about the
possibility that our minds are flawed. The First Meditation texts
are somewhat ambiguous on this count. But later passages are very
clear
(a theme we'll develop more fully in
 Section 4.3).



What is essential to the doubt is not the specific story about the
origin of our cognitive wiring; it's instead the realization
- regardless the story - that for all we know, our
cognitive wiring is flawed. Even so, I regularly speak in terms of the
*evil genius* (following Descartes' lead), as a kind of
mnemonic for the more general doubt about our cognitive nature.



Having introduced the Evil Genius Doubt, the First Meditation program
of demolition is not only *hyperbolic* but *universal*.
As the meditator remarks, I "am finally compelled to admit that
there is not one of my former beliefs about which a doubt may not
properly be raised" (Med. 1, AT 7:21, CSM 2:14f). As will
emerge, the early paragraphs of the Third Meditation clarify a further
nuance of the Evil Genius Doubt - a nuance consistently observed
thereafter. Descartes clarifies, there, that the Evil Genius Doubt
operates in an *indirect* manner (a topic to which we return in
 Section 4.3).



(For examples of alternative interpretations of the Evil Genius Doubt, 
see Gewirth 1941 and Wilson 1978.)


## 4. The *Cogito* and Doubt


### 4.1 *Cogito Ergo Sum*



Famously, Descartes puts forward a very simple candidate as
(what CSM translate as being) the "first item of knowledge
[*cognition*]" (Med. 3, AT 7:35, CSM 2:24). The
candidate is suggested by methodical doubt - by the very
effort at thinking *all* my thoughts might be mistaken.
Early in the Second Meditation, the meditator observes:



> 
> I have convinced myself that there is absolutely nothing in the world,
> no sky, no earth, no minds, no bodies. Does it now follow that I too
> do not exist? No: if I convinced myself of something then I certainly
> existed. But there is a deceiver of supreme power and cunning who is
> deliberately and constantly deceiving me. In that case I too
> undoubtedly exist, if he is deceiving me; and let him deceive me as
> much as he can, he will never bring it about that I am nothing so long
> as I think that I am something. So after considering everything very
> thoroughly, I must finally conclude that this proposition, *I
> am*, *I exist*, is necessarily true whenever it is put
> forward by me or conceived in my mind. (AT 7:25, CSM 2:16f)
> 



As the canonical formulation has it, *I think therefore I
am* (Latin: *cogito ergo sum*; French: *je pense*, 
*donc je suis*) - a formulation that does not
expressly appear in the *Meditations*. Descartes regards
the '*cogito*' (as it is often referred to) as
the "first and most certain of all to occur to anyone who
philosophizes in an orderly way" (*Prin*. 1:7, AT8a:7,
CSM 1:195).



Is the great certainty of the *cogito* supposed to attach
to the "I think," the "I am," or the
"therefore" (i.e., their logical relation)? Presumably,
it must attach to all of these, if the *cogito* is to play the
foundational role Descartes assigns to it. But this answer can seem to
depend on whether the *cogito* is understood as an inference or
an intuition - an issue we address below.



Testing the *cogito* by means of methodical doubt is supposed
to reveal its unshakable certainty. Hyperbolic doubt helps me
appreciate that the existence of my body is subject to doubt, whereas
the existence of my thinking is not. The very attempt at *thinking
away my thinking* is indeed self-stultifying.



The *cogito* raises numerous philosophical questions and has
generated an enormous literature. The most significant ongoing debate
concerns whether Descartes intends the *cogito* to be an
*intuition* (i.e., roughly, self-evident), or instead an
*inference*.



In an influential 1962 paper, Jaakko Hintikka's argues that it

should be understood non-inferentially, as a performative utterance.
On his analysis, *I exist* doesn't follow logically from
*I think*, nor does Descartes suppose otherwise. Rather, the
transition from *I think* to *I exist* is non-logical
- indeed, the statement that "I do not exist" is not
logically incoherent. The key point, according to Hintikka, is that
the very act of *thinking* that statement - the cognitive
performance - is *existentially* incoherent: I cannot
both think the statement *and* believe it to be true. Hintikka
takes the emphasis on "cogito" as intended "to
express the performatory character of Descartes's insight; it
refers to the 'performance' (to the act of thinking)
through which the sentence 'I exist' may be said to verify
itself" (1962, 17).



The following Second Replies text can seem supportive of a
non-inferential reading:



> 
> When someone says "I am thinking, therefore I am, or I
> exist," he does not deduce existence from thought by means of a
> syllogism, but recognizes it as something self-evident by a simple
> intuition of the mind. (Replies 2, AT 7:140, CSM 2:100)
> 



However, as Margaret Wilson correctly observes, "the claim that
the *cogito* is an inference ... is not equivalent to
the claim that it is a syllogism" (1978, 56). The passage only
expressly rejects the effort to understand the *cogito* in
terms of syllogism, but not necessarily in terms of inference.



Further, it should be noted that inferential interpretations need not
reject that the *cogito* counts *also* as an intuition.
There's no inconsistency in claiming a self-evident grasp of a
proposition that has inferential structure. It is indeed widely held
among philosophers that *modus ponens* is self-evident, yet it
contains an inference. In short, that a statement *contains* an
inference does not entail that one's acceptance of it is
*grounded* in inference - a fact applicable to the
*cogito*. Edwin Curley helpfully notes that Descartes
"consistently blurs the distinction between inferences and
propositions by referring to the whole formula 'I think,
therefore I am' as a truth, a first principle, a proposition,
and a conclusion" (1978, 79). Anthony Kenny adds that, for 
Descartes, "what is from one point of view intuited is from 
another point of view deduced" (1968, 55), citing
*Rules* 3 as support.



A related point concerns the absence of an express
'*ergo*' ('therefore') in the Second
Meditation account - as if thereby indicating the absence of 
inference in that passage. However, the Second Meditation passage
is arguably the one place (of his various published treatments)
where Descartes explicitly *details* a line of inferential 
reflection leading up to the conclusion that *I am*, *I 
exist*. His other treatments merely *say* the 
'therefore'; the Second Meditation unpacks it.



Whatever the *cogito*'s inferential status, it is
worth noting a twofold observation of Barry Stroud: "a
thinker obviously could never be wrong in thinking 'I
think'," moreover, "no one who thinks could
think falsely that he exists" (2008, 518).



Further issues about the *cogito* are worth clarifying
- let's cover a few points in summary fashion. First,
a first-person formulation is essential to the certainty of the
*cogito*. Third-person claims, such as "Icarus
thinks," or "Descartes thinks," are not unshakably
certain - not for *me*, at any rate; only the occurrence
of *my* thought has a chance of resisting hyperbolic doubt.
There are a number of passages in which Descartes refers to a
third-person version of the *cogito*. But none of these occurs
in the context of establishing the actual existence of a particular
thinker (in contrast with affirming the conditional, general result 
that *whatever thinks exists*).



Second, a present tense formulation is essential to the certainty of
the *cogito*. It's no good to reason that "I
existed last Tuesday, since I recall that I was thinking on that
day." For all I know, I'm now merely dreaming about that
occasion. Nor does it work to reason that "I'll continue
to exist, since I'm now thinking." As the meditator
remarks, "it could be that were I totally to cease from
thinking, I should totally cease to exist" (Med. 2, AT 7:27, CSM
2:18). The privileged certainty of the *cogito* is grounded in
the "manifest contradiction" (AT 7:36, CSM 2:25) of trying
to think away my *present* thinking.



Third, the certainty of the *cogito* depends on being
formulated in terms of *cogitatio* - i.e., my thinking,
or awareness/consciousness more generally. Any mode of thinking is
sufficient, including doubting, affirming, denying, willing,
understanding, imagining, and so on (cf. Med. 2, AT 7:28). My
*bodily* activities, however, are insufficient. For instance,
it's no good to reason that "I exist, since I am
walking," because methodical doubt calls into question the
existence of my legs. Maybe I'm just dreaming that I have legs.
A simple revision, such as "I exist, since it *seems*
I'm walking," restores the anti-sceptical potency (cf.
Replies 5, AT 7:352; *Prin*. 1:9).



Fourth, a caveat is in order. That Descartes rejects formulations
presupposing the existence of a body commits him to no more than an
epistemic distinction between the ideas of mind and body, but not
(yet) an ontological distinction (as in mind-body dualism). Indeed, in
the passage following the *cogito*, Descartes has his meditator
say: 



> 
> And yet may it not perhaps be the case that these very things which I
> am supposing to be nothing [e.g., "that structure of limbs which
> is called a human body"], because they are unknown to me, are in
> reality identical with the "I" of which I am aware? I do
> not know, and for the moment I shall not argue the point, since I can
> make judgements only about things which are known to me. (Med. 2, AT
> 7:27, CSM 2:18)
> 



In short, the intended epistemic success of the *cogito* does
not presuppose any particular mind-body ontology.



Finally, Descartes' reference to an "I", in the
"I think," is not intended to presuppose the existence of
a *substantial* self. In the very next sentence following the
initial statement of the *cogito*, the meditator says:
"But I do not yet have a sufficient understanding of what this
'I' is, that now necessarily exists" (AT 7:25, CSM
2:17). As Stephen Menn writes:



> 
> Although the Meditator now knows *that* he is, he does not seem
> to know *what* he is: his old conception of his nature has been
> called into doubt, and he does not seem to have anything new to
> replace it. (1998, 249)
> 



The *cogito* purports to yield certainty that I exist
*insofar as* I am a thinking thing, *whatever that turns out
to be*. The ensuing discussion is intended to help arrive at an
understanding of the ontological nature of the thinking subject.



More generally, we should distinguish issues of epistemic and
ontological dependence. In the final analysis, Descartes thinks he
shows that the occurrence of thought depends (ontologically) on the
existence of a substantial self - to wit, on the existence of an
infinite substance, namely God (cf. Med. 3, AT 7:48ff). But he denies
that an acceptance of these ontological matters is epistemically prior
to the *cogito*: its certainty is not supposed to depend
(epistemically) on the abstruse metaphysics that Descartes thinks he
eventually establishes. (See Vinci 1998 for an alternative
reading.)



If the *cogito* does not presuppose a substantial self, what
then is the epistemic basis for injecting the 'I' into the
"I think"? Some critics have complained that, in referring
to the "I", Descartes begs the question by presupposing
what he means to establish in the "I exist." Among the
critics, Bertrand Russell objects that "the word 'I'
is really illegitimate." Echoing the 18th century thinker, Georg
Lichtenberg, Russell writes that Descartes should have, instead,
stated "his ultimate premiss in the form 'there are
thoughts'." Russell adds that "the word
'I' is grammatically convenient, but does not describe a
datum" (1945, 567). Accordingly, "there is pain" and
"I am in pain" have different contents, and Descartes is
entitled only to the former.



One effort at reply has it that introspection reveals more than what
Russell allows - it reveals the *subjective* character of
experience. On this view, there is more to the experiential story of
*being in pain* than is expressed by saying that *there is
pain*: the experience includes the feeling of pain plus a
*point-of-view* - an experiential addition that's
difficult to characterize except by adding that "I" am in
pain, that the pain is *mine*. Importantly, my awareness of
this subjective feature of experience does not depend on an awareness
of the metaphysical nature of a thinking subject. If we take Descartes
to be using 'I' to signify this subjective character, then
he is not smuggling in something that's not already there: the
"I"-ness of consciousness turns out to be (contra Russell)
a primary datum of experience. And though, as Hume persuasively
argues, introspection reveals no *sense impressions* suited
to the role of a thinking subject, Descartes, unlike Hume, has no
need to derive all our ideas from sense impressions. Descartes' 
idea of the self does ultimately draw on innate conceptual 
resources.



Setting aside the philosophical concerns associated with the
*cogito*, let's turn to a further interpretive
concern: namely, the issue of whether, at its initial introduction
(in the Second Meditation), Descartes intends that the
*cogito* counts as perfect knowledge.


### 4.2 Does the *Cogito* count as (Atheist-Available) Perfect Knowledge?



The extraordinary certainty and doubt-resistance of the
*cogito* marks an Archimedean turning point in the
meditator's inquiry. However, there are interpretive disputes
about whether Descartes intends the *cogito* to count -
at its initial introduction, prior to the arguments for God - as
*fully* indubitable, and therefore as perfect knowledge. It is
quite common to interpret the *cogito* as being the first item
of perfect knowledge. In
 Section 6.1
 we'll explore how such interpretations (i.e., Bounded Doubt
Interpretations) render Descartes' broader argument. But here,
I want to develop the textual case for holding that even the 
*cogito* is undermined by Evil Genius Doubt.



There is no disputing that Descartes characterizes the *cogito*
as the "first item of knowledge [*cognitione*]"
(Med. 3, AT 7:35, CSM 2:24), and as the first "piece of
knowledge [*cognitio*]" (*Prin*. 1:7, AT 8a:7, CSM
1:195). Noteworthy, however, is the Latin terminology Descartes uses
in these characterizations ('*cognitio*' and its
cognates). As noted at the outset, Descartes is a contextualist in the
sense of invoking the notion of *knowledge* in divergent
contexts that presuppose very different epistemic standards. Of
particular interest is that he expressly clarifies that contexts aptly
characterized in terms of *cognitio*-talk do not necessarily
count as perfect knowledge:



> 
> The fact that an atheist can be "clearly aware [*clare
> cognoscere*] that the three angles of a triangle are equal to two
> right angles" is something I do not dispute. But I maintain that
> this awareness [*cognitionem*] of his is not true knowledge
> [*scientiam*], since no act of awareness [*cognitio*]
> that can be rendered doubtful seems fit to be called knowledge
> [*scientia*]. Now since we are supposing that this individual
> is an atheist, he cannot be certain that he is not being deceived on
> matters which seem to him to be very evident (as I fully explained).
> (Replies 2, AT 7:141, CSM 2:101)
> 



This alone does not prove that the *cogito* is not intended
to count as perfect knowledge (at its initial occurrence, in the
Second Meditation). However, it does undercut the argument
whereby *calling* it the "first item of knowledge"
shows that Descartes intends it as perfect knowledge.



More generally, a wide range of clear texts support (what I'll
call) the No Atheistic Perfect Knowledge Thesis - a thesis with
implications for the debate about the *cogito*. Consider the
following texts, each arising in a context of clarifying the
requirements of perfect knowledge (italics are added):



> 
> 
> For if I do not know this [i.e., "whether there is a God, and,
> if there is, whether he can be a deceiver"], it seems that I can
> never be quite certain *about anything else*. (Med. 3, AT 7:36,
> CSM 2:25)
> 
> 
> 
> I see that the certainty of *all* other things depends on this
> [i.e., "that the supreme being exists"], so that without
> it *nothing* can ever be perfectly known [*perfecte
> sciri*]. (Med. 5, AT 7:69, CSM 2:48)
> 
> 
> 
> [I]f I were unaware of God ... I should thus never have true and
> certain knowledge [*scientiam*] *about anything*, but
> only shifting and changeable opinions. (Med. 5, AT 7:69, CSM 2:48)
> 
> 
> 
> Thus I see plainly that the certainty and truth of *all*
> knowledge [*scientiae*] depends uniquely on my awareness of the
> true God, to such an extent that I was incapable of perfect knowledge
> [*perfecte scire*] *about anything else* until I became
> aware of him. (Med. 5, AT 7:71, CSM 2:49)
> 
> 
> 



These texts make a powerful case that *nothing* else can be
perfectly known *prior* to establishing that we're
created by an all-perfect God, rather than an evil genius. Indeed,
Descartes' express wording seems intended to rule-out any 
exceptions. The first text is particularly noteworthy, because it
comes at the end of a paragraph which includes reference to the 
*cogito*. As Curley writes:



> 
> Notice that Descartes does *not* say: until I know whether God
> exists and can be a deceiver I cannot be certain of *anything
> except the existence of the self and its thoughts*. He says he
> cannot be certain of *anything*. (2006, 40)
> 



Descartes looks to hold that hyperbolic doubt is utterly unbounded
- i.e., that it undermines *all* manner of propositions,
including thereby the proposition that "I exist."



We can indeed read the opening paragraphs of the Third Meditation as
intended to clarify not that the *cogito* is perfectly known,
but instead the following twofold point: First, that what underwrites
the *cogito*'s epistemic impressiveness is
*clarity* and *distinctness*. Second, that even
cognitions this impressive can be undermined by Evil Genius Doubt, and
thus lack the *full* indubitability of perfect knowledge.



Regarding the first point, the Third Meditation opens with meditator
attempting to build on the apparent success of the *cogito*.
What are the internal marks of this impressive perception -
*what is it like* to have perception that good? The answer:



> 
> I am certain that I am a thinking thing. Do I not therefore also know
> what is required for my being certain about anything? In this first
> item of knowledge [*cognitione*] there is simply a clear and
> distinct perception of what I am asserting. (AT 7:35, CSM 2:24)
> 



The next two paragraphs help clarify (among other things) what
Descartes takes to be epistemically impressive about clear and
distinct perception, in contrast with external sense perception.
Of external sensation, the third paragraph offers this:



> 
> Yet I previously accepted as wholly certain and evident many things
> which I afterwards realized were doubtful. What were these? The earth,
> sky, stars, and everything else that I apprehended with the senses.
> But what was it about them that I perceived clearly? Just that the
> ideas, or thoughts, of such things appeared before my mind. Yet even
> now I am not denying that these ideas occur within me. ... Here
> was my mistake; or at any rate, if my judgement was true, it was not
> thanks to the strength of my perception. (AT 7:35, CSM 2:24f)
> 



Though we regularly form judgments based on external sensation, they
are easily undermined by sceptical doubt, as shown by the Now Dreaming
Doubt. By contrast, our clear and distinct perceptions enjoy a
perceptual "strength" enabling us to ward off even the
Evil Genius Doubt (at least, so it might seem). The fourth paragraph
offers this:



> 
> But what about when I was considering something very simple and
> straightforward in arithmetic or geometry, for example that two and
> three added together make five, and so on? Did I not see at least
> these things clearly enough to affirm their truth? ... when I
> turn to the things themselves which I think I perceive very clearly, I
> am so convinced by them that I spontaneously declare: let whoever can
> do so deceive me, he will never bring it about that I am nothing, so
> long as I continue to think I am something ... or bring it about
> that two and three added together are more or less than five, or
> anything of this kind in which I see a manifest contradiction. (AT
> 7:36, CSM 2:25)
> 



Prima facie, this excerpt suggests that multiple propositions are
- at this pre-theistic stage of the broader argument -
fully indubitable, thereby counting as perfect knowledge. But there
is more to the paragraph; which brings us to the second point noted 
above, namely, that even cognitions this impressive can be undermined 
by Evil Genius Doubt - an outcome clarified in the final lines
of this same paragraph:



> 
> For if I do not know this [i.e., "whether there is a God, and,
> if there is, whether he can be a deceiver"], it seems that I can
> never be quite certain *about anything else*.
> 



In order to appreciate the subtleties of this pivotal fourth paragraph
of the Third Meditation, we need to clarify the *indirect*
manner in which Evil Genius Doubt operates on clear and distinct
perception.


### 4.3 How *Indirectly* to Doubt Clear and Distinct Perception



How *could* a doubt undermine the *cogito*? Part of its
impressiveness is that I cannot think about my existence without
affirming it, yet I cannot doubt my existence without thinking about
it. In short, I simply cannot doubt the proposition "I
exist" - or so it appears.



Seeming to reinforce further the suspicion that the *cogito*
cannot be doubted is a more general thesis Descartes holds concerning
the doubt-resistance of *any* matters that are clearly and
distinctly perceived:



> 
> 
> [T]he nature of my mind is such that I cannot but assent to these
> things, at least so long as I clearly perceive them. (Med. 5, AT 7:65,
> CSM 2:45)
> 
> 
> 
> [M]y nature is such that so long as I perceive something very clearly
> and distinctly I cannot but believe it to be true. (Med. 5, AT 7:69,
> CSM 2:48)
> 
> 
> 



How, then, is it possible to doubt such matters? According to one
interpretation, the answer is that we cannot doubt them
*directly*, however, we can doubt them in an *indirect*
manner. That is, rather than directing the doubt at particular such
propositions, as that *I exist*, or that 2+3=5, the doubt is
instead directed at the *cognitive faculties* by which we
apprehend such propositions. By way of analogy, consider that if a
calculator were defective, it would cast doubt on any calculations it
generated. Likewise, if my own mind were in some sense defective, this
would cast doubt on any matters I apprehended - no matter how
evident those matters might seem. By directing the doubt at the
veracity of my own cognitive faculties, I do thereby
*indirectly* doubt the particular propositions apprehended by
means of those faculties.



A wealth of texts support that this is how the Evil Genius Doubt is
intended to operate. Consider these (italics are added):



> 
> 
> [Perhaps some God could have given me a *nature such that I was
> deceived* even in *matters which seemed most evident*.
> (Med. 3, AT 7:36, CSM 2:25)
> 
> 
> 
> I can convince myself that I have a *natural disposition to go
> wrong* from time to time in *matters which I think I perceive
> as evidently as can be*. (Med. 5, AT 7:70, CSM 2:48)
> 
> 
> 
> I saw nothing to rule out the possibility that my *natural
> constitution made me prone to error* even in *matters which
> seemed to me most true*. (Med. 6, AT 7:77, CSM 2:53)
> 
> 
> 
> [T]he most serious doubt [arises] from our ignorance about whether our
> *nature might not be such as to make us go wrong* even in
> *matters which seemed to us utterly evident*. (*Prin*.
> 1:30; AT 8a:16, CSM 1:203)
> 
> 
> 



As each passage conveys, the doubt is directed not at the particular
object level propositions undermined, but at the possibility of our
having a defective cognitive nature. (In this vein, Carriero helpfully
refers to the doubt under the heading, 'imperfect-nature
doubt' [2009, 27], rather than Evil Genius Doubt; Newman and
Nelson refer to it as 'meta-cognitive doubt' [1999, 374].)
As each passage also conveys, the doubt effectively undermines even
the "most evident" of matters. Because the doubt is
indirect, it's blind to the particular propositions it
undercuts. The relevant question does arguably shift from,
"How *could* a doubt undermine
the *cogito*?", to "How could this doubt
*fail* to undermine even the *cogito*?"
Indeed, the first of the above passages expressly includes the
*cogito* with the list of example propositions being
indirectly called into doubt - this, in the pivotal fourth 
paragraph of the Third Meditation:



> 
> But what about when I was considering something very simple and
> straightforward in arithmetic or geometry, for example that two and
> three added together make five, and so on? Did I not see at least
> these things clearly enough to affirm their truth? Indeed, the only
> reason for my *later judgement* that they were open to doubt
> was that it occurred to me that perhaps some God could have given me a
> nature such that I was deceived even in matters which seemed most
> evident. And whenever my preconceived belief in the supreme power of
> God comes to mind, I cannot but admit that it would be easy for him,
> if he so desired, to bring it about that I go wrong even in those
> matters which I think I see utterly clearly with my mind's eye.
> Yet *when I turn to the things themselves* which I think I
> perceive very clearly, I am so convinced by them that I spontaneously
> declare: let whoever can do so deceive me, he will *never bring it
> about that I am nothing, so long as I continue to think I am
> something*; or make it true at some future time that I have never
> existed, since it is now true that I exist; or bring it about that two
> and three added together are more or less than five, or anything of
> this kind in which I see a manifest contradiction. (AT 7:35f, CSM
> 2:25; italics added)
> 



The suggestion is of an epistemic schizophrenia, of sorts, depending
on whether one's attention is directed at the object level
propositions, or instead at the possibility of our having defective
cognitive faculties:



> 
> 
> *Moments of epistemic optimism*: While I am directly attending
> to a proposition, perceiving it clearly and distinctly, I enjoy an
> irresistible cognitive luminance and my assent is compelled.
> 
> 
> 
> *Moments of epistemic pessimism*: When no longer directly
> attending - no longer perceiving the proposition clearly and
> distinctly - I can entertain the sceptical hypothesis that such
> feelings of cognitive luminance are epistemically worthless, indeed
> arising from a defective cognitive nature.
> 
> 
> 



Granted, this indirect doubt is exceedingly hyperbolic. Even so, it
entails that we lack the *full* indubitability requisite to
perfect knowledge. Descartes thus closes the pivotal fourth paragraph,
clarifying that because of the Evil Genius Doubt, *nothing*
(yet) meets the epistemic standard of perfect knowledge:



> 
> And since I have no cause to think that there is a deceiving God, and
> I do not yet even know for sure whether there is a God at all, any
> reason for doubt which depends simply on this supposition is a very
> slight and, so to speak, metaphysical one. But in order to remove even
> this slight reason for doubt, as soon as the opportunity arises I must
> examine whether there is a God, and, if there is, whether he can be a
> deceiver. For if I do not know this, it seems that I can never be
> quite certain about anything else. (AT 7:36, CSM 2:25)
> 



A later Third Meditation passage - but one occurring prior to
the arguments for God - can be taken to suggest a very different
interpretation. On this alternative account, some of the matters we
clearly and distinctly perceive *are* fully indubitable,
thereby counting as perfect knowledge even prior to knowledge of God.
The passage has Descartes drawing a distinction between what is
*revealed by the natural light*, and what is *taught by
nature*:



> 
> When I say "Nature taught me to think this," all I mean is
> that a spontaneous impulse leads me to believe it, not that its truth
> has been revealed to me by some natural light. There is a big
> difference here. Whatever is revealed to me by the natural light
> - for example that from the fact that I am doubting it follows
> that I exist, and so on - cannot in any way be open to doubt.
> This is because there cannot be another faculty both as trustworthy as
> the natural light and also capable of showing me that such things are
> not true. But as for my natural impulses, I have often judged in the
> past that they were pushing me in the wrong direction when it was a
> question of choosing the good, and I do not see why I should place any
> greater confidence in them in other matters. (AT 7:38f, CSM 2:26f)
> 



The passage makes clear that the *cogito* is revealed by
the natural light; and on one plausible reading, it conveys that
the *cogito* is utterly immune to doubt - i.e., it 
"cannot in any way be open to doubt." On this
understanding, the scope of Evil Genius Doubt is *bounded*,
in the sense that not all propositions are vulnerable to the doubt. 
This is to say that some propositions, including the *cogito*, 
may be fully indubitable, thus satisfying the requirements of
perfect knowledge - even for atheists.



Defenders of an *unbounded* doubt interpretation would offer
a different analysis of the passage. First, we saw that Descartes
earlier claimed that what grounds the extraordinary certainty of the
*cogito* is that "there is simply a clear and distinct
perception." Yet, that earlier claim is surprising, if the point
of the above passage is that the *natural light* is
epistemically superior to mere garden variety clarity and
distinctness. A remark Descartes makes to Hobbes is relevant:
"As everyone knows, a 'light in the intellect' means
transparent clarity of cognition" (Replies 3, AT 7:192, CSM
2:135). This suggests that "natural light" references are
simply another way of talking about clear and distinct perception. On
this point, Carriero notes: "I do not see an important
distinction for Descartes between something's being revealed to
me by the light of nature and my perceiving clearly that thing's
being the case" (2008, 305). Note further that a bounded doubt
interpretation of this passage is at odds with the numerous other
passages we've examined indicating that even the *cogito*
is vulnerable to the Evil Genius Doubt.



How, then, do unbounded doubt interpreters deal with this passage?
In context, the point of the natural light passage is not to draw
a distinction between two grades of clear and distinct perception;
it's instead to clarify the distinction between the kind of
probabilistic reasoning the meditator had invoked in prior remarks,
and the irresistible evidentness accompanying our very best
cognitions, such as the *cogito*. We can indeed take the point
of the passage to apply to moments of careful attention: even while
directly attending to the probabilistic matters (taught by nature), we
recognize that there are grounds for doubt; whereas, when directly
attending to our epistemically best cognitions (revealed by the
natural light), we simply cannot doubt them. This reading renders the
passage continuous with our reading of the other passages. Again, in
the pivotal fourth paragraph of the Third Meditation: "when I
turn to the things themselves which I think I perceive very clearly,
I am so convinced by them that I spontaneously declare: let whoever
can do so deceive me, he will never bring it about that I am nothing, 
so long as I continue to think I am something"; i.e.,
*while* directly attending to them, the matters revealed by the
natural light "cannot in any way be open to doubt." And
yet, upon diverting attention, they fall prey to the Evil Genius
Doubt.



(For further discussion of the *cogito*, see Beyssade 1993, 
Broughton 2002, Carriero 2009, Cunning 2007, Curley 1978, 
Frankfurt 1966, Hintikka 1962, Kenny 1968, Markie 1992, 
Peacocke 2012, Sarkar 2003, Stroud 2008, Vendler 1984,
Vinci 1998, Williams 1978, and Wilson 1978.)


## 5. C&D Rule and the Road to Perfect Knowledge


### 5.1 Clarity and Distinctness as a *Provisional* Truth Rule



Recall that Descartes characterizes the *cogito* as an
Archimedean point, of sorts, in his constructive efforts at finding
something "certain and unshakeable." It is clear how the
*cogito* serves this role on bounded doubt interpretations,
since they render it as being fully immune to the Evil Genius Doubt
- indeed, as providing the initial item of perfect knowledge.
But what about unbounded doubt interpretations: in rendering
the *cogito* as being subject to Evil Genius Doubt, how do they
explain its Archimedean role in the broader project? One answer is
that insofar as the *cogito* is the first cognition noticed to
resist any efforts at a *direct* doubt, it can be said to play
an Archimedean role. For it exemplifies the kind of cognitions the
meditator thereafter employs, in all subsequent constructive efforts
to overcome the sceptical problem.



Descartes indeed uses the *cogito* to clarify the epistemically
privileged status of clear and distinct perception, even formulating
clarity and distinctness as underwriting a general *rule* for
discovering truth. The passage occurs in the second paragraph of the
Third Meditation:



> 
> In this first item of knowledge there is simply a clear and distinct
> perception of what I am asserting; this would not be enough to make me
> certain of the truth of the matter if it could ever turn out that
> something which I perceived with such clarity and distinctness was
> false. So I now seem [*videor*] to be able to lay it down as a
> general rule that whatever I perceive very clearly and distinctly is
> true. (AT 7:35, CSM 2:24)
> 



I shall refer to this general rule the 'C&D Rule'.
Though interpretations differ, the context of the passage indicates
the rule is treated as *provisional* - i.e., further work
will be needed before the rule can be regarded as finally established.
On two counts, the announcement of the rule is carefully tinged with
caution, in anticipation of the revelation to come (two paragraphs
later) that even clearly and distinctly perceived matters are
vulnerable to the Evil Genius Doubt. First, the passage notes that
being clearly and distinctly perceived "would not be enough to
make me certain of the truth of the matter," if the truth of
such matters could be undermined. Second, the announcement includes an
important qualification, in saying that it does "now seem"
(*videor*) that this is a justified rule. Because it soon
emerges that the Evil Genius Doubt undermines the veracity of the
C&D Rule, Descartes assumes the burden of trying to *establish* 
the rule - a proof he takes to occur not in this early Third
Meditation passage, but only later, after having argued for an
all-perfect God: Descartes writes that it is "in the Fourth 
Meditation [that] it is proved that everything that we clearly and 
distinctly perceive is true" (Synopsis, AT 7:15, CSM 2:11).
 (Section 5.3
 discusses Descartes' Fourth Meditation argument for the C&D
Rule.)


### 5.2 Strategy for Constructive Proofs 
Moving Forward



If even clear and distinct perception is subject to doubt, how is
the meditator to make progress? How can he construct arguments in
the effort to solve the sceptical problem? This brings into focus
the issue of whether Descartes' procedure is viciously
*circular*. For it seems that in the very process of
*arguing* for a truth rule, he is already employing that 
very rule. For now, we'll set to the side the issue of 
circularity (returning to it in
 Section 6).



In his strategy for making constructive arguments, Descartes builds on
the fact that clearly and distinctly perceived matters appear to us to
be utterly conclusive, i.e., *while* our perception is clear and
distinct. So, by employing none other than premises and reasoning that
are clearly and distinctly perceived, we can - in some sense
- make rational progress, notwithstanding that those very same 
proofs fall vulnerable to indirect doubt, once our attention is no 
longer clear and distinct. The following Fifth Meditation passage illustrates the point:



> 
> Admittedly my nature is such that so long as I perceive something very
> clearly and distinctly I cannot but believe it to be true. But my
> nature is also such that I cannot fix my mental vision continually on
> the same thing, so as to keep perceiving it clearly; and often the
> memory of a previously made judgement may come back, when I am no
> longer attending to the arguments which led me to make it. And so
> other arguments can now occur to me which might easily undermine my
> opinion, if I were unaware of [the true] God; and I should thus never
> have true and certain knowledge about anything, but only shifting and
> changeable opinions. For example, when I consider the nature of a
> triangle, it appears most evident to me, steeped as I am in the
> principles of geometry, that its three angles are equal to two right
> angles; and so long as I attend to the proof, I cannot but believe
> this to be true. But as soon as I turn my mind's eye away from
> the proof, then in spite of still remembering that I perceived it very
> clearly, I can easily fall into doubt about its truth, if I am unaware
> of God. For I can convince myself that I have a natural disposition to
> go wrong from time to time in matters which I think I perceive as
> evidently as can be. (Med. 5, AT 7:69f, CSM 2:48; cf. AT 3:64f; AT
> 8a:9f).
> 



Of course, Descartes will need some sort of final solution to the
problem of ongoing indirect doubt. In the meantime, he has his
meditator attempting to move forward, by constructing clearly and
distinctly perceived anti-sceptical arguments.



The broader argumentative strategy is revealed at the end of the
pivotal fourth paragraph of the Third Meditation: "in order to
remove even this slight reason for doubt, as soon as the opportunity
arises I must examine whether there is a God, and, if there is,
whether he can be a deceiver." So, in the effort to establish
the C&D Rule, the meditator makes arguments to the conclusion that
his creator is not an evil genius, but an all-perfect creator who
would not allow him to be deceived about what he clearly and
distinctly perceives.



The broader argument encompasses two main steps. The first main
step involves Third Meditation arguments for the existence of an
all-perfect God. From these arguments the meditator concludes:



> 
> I recognize that it would be impossible for me to exist with the
> kind of nature I have - that is, having within me the idea
> of God - were it not the case that God really existed. By
> 'God' I mean the very being the idea of whom is within me,
> that is, the possessor of all the perfections which I cannot grasp,
> but can somehow reach in my thought, who is subject to no defects
> whatsoever. It is clear enough from this that he cannot be a deceiver,
> since it is manifest by the natural light that all fraud and deception
> depend on some defect. (Med. 3, AT 7:51f, CSM 2:35)
> 



There is much of interest in Descartes' Third Meditation
arguments for an all-perfect creator God. (Note that the Fifth
Meditation advances a further argument for God.) In the interests
of space, and of focusing on epistemological concerns, however,
these arguments will not be considered here. (For an overview of
Descartes' proofs, see Nolan 2014 and Nolan & Nelson
2006.)



The second main step involves an argument from the premise (now
established) that an all-perfect God exists, to the general veracity
of the C&D Rule - whereby, whatever is clearly and
distinctly perceived is guaranteed to be true. It is this second
main step of the broader argument to which we now turn. (As will
emerge, a yet further, third step is required on some
interpretations.)


### 5.3 Fourth Meditation Proof of the C&D Rule



It might seem that a separate argument for the C&D Rule is
unneeded - that having demonstrated a non-deceiving God, the
veracity of the rule is a straightforward consequence. But this is too
fast. Why should *only* the C&D Rule be a straightforward
consequence, but not also a more general infallibility of *all*
our judgments? Essentially this point is made in the First Meditation,
at the introduction of the Evil Genius Doubt. As we saw, the meditator
there observes that what seems to follow from the standard view
- whereby God "is said to be supremely good," rather
than a deceiver - is that God would not allow us *ever*
to be mistaken in our judgments:



> 
> But if it were inconsistent with his goodness to have created me such
> that I am deceived all the time, it would seem equally foreign to his
> goodness to allow me to be deceived even occasionally; yet this last
> assertion cannot be made. (Med. 1, AT 7:21, CSM 2:14)
> 



In short, the most straightforward consequence of an all-perfect
creator would seem to be the universal rule: *If I form a judgment,
then it is true*. Yet quite clearly, *this* rule
doesn't hold. What emerges is an instance of the problem of
evil, here applied to judgment error. As the passage reasons:


1. Judgment error occurs.
2. That judgment error occurs is incompatible with the hypothesis
that I am the creation of an all-perfect God.
3. Therefore, I am not the creation of an all-perfect God.



These First Meditation remarks set the stage for the discussion
that comes in the Fourth Meditation. Descartes needs a theodicy
for error - *theodicy* being an effort to explain how
an all-perfect God is compatible with evil. The theodicy needs to
show that the existence of such a God is compatible with some forms
of judgment error, but not others; somehow, God allows error in our 
sensory judgments, while guaranteeing the inerrancy of judgments
based on clear and distinct perception. In contrast with the First 
Meditation setting, the context of the Fourth Meditation comes on
the heels of a demonstration of the existence of an all-perfect
God. The argument of the Fourth Meditation thus begins by reviewing
the problem where the First Meditation left it, but in the light of
the meditator's newfound conclusion - "to begin
with, I recognize that it is impossible that God should ever deceive 
me." The passage continues:



> 
> Next, I know by experience that there is in me a
> faculty of judgement which, like everything else which is in me, I
> certainly received from God. And since God does not wish to deceive
> me, he surely did not give me the kind of faculty which would ever
> enable me to go wrong while using it correctly.
> 
> 
> There would be no further doubt on this issue
> were it not that what I have just said appears to imply that I am
> incapable of ever going wrong. For if everything that is in me comes
> from God, and he did not endow me with a faculty for making mistakes,
> it appears that I can never go wrong. (Med. 4, AT 7:53f, CSM 2:37f)
> 
> 
> 



Seeking to resolve the problem, the meditator investigates the
causes of error. In the course of the discussion, Descartes puts 
forward his theory whereby judgment arises from the cooperation
of the *intellect* and the *will*: the role of the 
intellect is to consider a perceptual content - i.e.,
something seeming to be the case, thereby functioning as a
possible judgment; the role of the will is to give assent (or
dissent), or withhold assent, to the perceptual content under 
consideration.



The investigation concludes that the blameworthy cause of error
lies in our improper use of our free will. Neither the intellect
nor the will is inherently defective (though each is, of course,
finite), nor is there inherent defect in the design of how they 
cooperate - i.e., their design does not render error
inevitable. The design does make for the possibility of error,
in that "the scope of the will is wider than that of the 
intellect": my will is able to assent to further matters
than just those that I clearly and distinctly understand; "but 
instead of restricting it within the same limits, I extend its use
to matters which I do not understand" (AT 7:58, CSM 2:40).
In short, actual mistakes of judgment arise from user error:



> 
> [If] I simply refrain from making a judgement in cases where I do not
> perceive the truth with sufficient clarity and distinctness, then it
> is clear that I am behaving correctly and avoiding error. But if in
> such cases I either affirm or deny, then I am not using my free will
> correctly. (Med. 4, AT 7:59, CSM 2:41)
> 



The theodicy that emerges is a version of the free will defense.
Accordingly, we should thank God for giving us free will, but the cost
of having free will is the possibility of misusing it. Since error is
the result of misusing our free will, we should not blame God.



Not only is the theodicy used to explain the kinds of error God
*can* allow, it serves to clarify the kinds of error God
*cannot* allow. From the latter arises a proof of the C&D
Rule. God can allow errors that are *our* fault, but not errors
that would be *God's* fault. On occasions when my
perception is clear and distinct, my assent is involuntary and thus
not a result of a *misuse* of my free will. In such cases,
assent is a necessary consequence of my cognitive nature - a
point made in many passages, as we've seen: "our mind is
of such a nature that it cannot help assenting to what it clearly
understands" (AT 3:64, CSMK 147). Since, on occasions of clarity
and distinctness, my assent is the unavoidable consequence of my
God-given cognitive nature, God would properly get the blame if those
judgments resulted in error. Therefore, they are not in error; indeed
they *could* not be. That an evil genius might have created me
casts doubt on my clear and distinct judgments. That, instead, an
all-perfect God created me guarantees that these judgments are true. A
clever strategy of argument thus unfolds - effectively inverting
the usual reasoning in the problem of evil:


1. I am the creation of an all-perfect God.
2. That I am the creation of an all-perfect God is incompatible with
the sceptical hypothesis that I am in error about what I clearly and
distinctly perceive.
3. Therefore, I am not in error about what I clearly and distinctly
perceive.



The first premise is argued in the Third Meditation. The second
premise arises from the discussion of the Fourth Meditation. The
result is a divine guarantee of the C&D Rule. Whatever I perceive
clearly and distinctly is guaranteed true, because I am the creature
of an all-perfect God.



It might seem that, by the end of the Fourth Meditation, 
Descartes' broader case to overcome radical doubt is complete. 
At that stage, the meditator is in position to reproduce a 
demonstration - each step of which he clearly and distinctly 
perceives - which supports the grand conclusion that he's
the creation of an all-perfect God who would not allow him to be 
mistaken about whatever he perceives clearly and distinctly. However,
there are significant issues that must be addressed. Among the
philosophical concerns is that the demonstration itself looks 
suspiciously circular - the so-called Cartesian Circle. A
further issue arises in connection with the interpretation we
have been developing: for when the meditator is no longer clearly
and distinctly perceiving the steps of the demonstration, the
grand conclusion can then be undermined by means of the Evil Genius
Doubt; i.e., it would seem that perfect knowledge is not yet within
the meditator's grasp. Perhaps related is that at the close
of the Fourth Meditation one finds no announcement of victory over
the Evil Genius Doubt; instead, the announcement comes at the end
of the Fifth Meditation. But why? It is to such issues that we
now turn.



## 6. Perfect Knowledge, Circularity, and Truth


### 6.1 The Cartesian Circle



Students of philosophy can expect to be taught a longstanding
interpretation according to which Descartes' broader argument
is viciously circular. He first argues from clearly and distinctly
perceived premises to the conclusion that an all-perfect God exists;
he then argues from the premise that an all-perfect God exists to the
conclusion that whatever is clearly and distinctly perceived is true.
The worry is that he presupposes the C&D Rule in the effort to
prove the C&D Rule. Despite its prima facie plausibility,
Descartes scholarship generally resists the vicious circularity
interpretation, based on numerous textual considerations. But even
putting those texts to the side, it should be surprising that the
project would be viciously circular. As Thomas Lennon notes:



> 
> [I]t would be nothing less than astonishing if the central argument
> of the central text of the central figure of the central period in
> the history of philosophy were obviously circular. How could the
> father of modern philosophy, the source of the epistemological turn, 
> have produced such an obviously loopy argument? (2008, 158)
> 



Consider first what every plausible interpretation must concede:
that the two main steps of the broader argument unfold in a manner
*suggestive* of a circle - let us indeed refer to them as
'arcs'. The Third Meditation arguments for God define one
arc:



> 
> **Arc 1**: The conclusion that an all-perfect God exists
> is derived from premises that are clearly and distinctly perceived.
> 



The Fourth Meditation argument defines a second arc:



> 
> **Arc 2**: The general veracity of propositions that are
> clearly and distinctly perceived (i.e., the C&D Rule) is derived
> from the conclusion that an all-perfect God exists.
> 



That the broader argument unfolds in accord with these two steps is
uncontroversial. The question of interest concerns whether, strictly
speaking, these arcs form an epistemic *circle*. The statement
of Arc 1 admits of some ambiguity. How one resolves this ambiguity 
determines whether the arcs strictly form a circle. Let's begin 
by clarifying what Arc 1 would have to mean to generate vicious 
circularity. We'll then consider the main alternative 
interpretations of that arc by which commentators seek to avoid 
circularity.



> 
> 
> **Vicious Circularity interpretation**:
> 
> 
> 
> **Arc 1**: The conclusion that an all-perfect God exists
> is derived from premises that are clearly and distinctly perceived
> - *i.e., premises that are accepted only because of having
> first accepted the general veracity of propositions that are clearly
> and distinctly perceived*.
> 
> 
> 
> **Arc 2**: The general veracity of propositions that are
> clearly and distinctly perceived is derived from the conclusion that
> an all-perfect God exists.
> 
> 
> 



Thus rendered, Descartes' broader argument *is* viciously
circular. The italicized segment of Arc 1 marks an addition to the
original statement of it, thereby clarifying the circularity reading.
Interpreted in this way, Descartes begins his Third Meditation proofs
of God by presupposing the general veracity of clear and distinct
perception. That is, he starts by assuming the C&D Rule and then
uses the rule in the course of demonstrating it. Evidently, this way
of reading Descartes' argument has pedagogical appeal, for it is
widely taught (outside of Descartes scholarship) despite the absence
of serious textual merit. If there is one point of general agreement
in the scholarly literature, it is that the texts do not sustain this
interpretation.



How then should Arc 1 be understood? There are multiple
interpretations that avoid vicious circularity, along with
numerous schemes for cataloguing them. For present purposes, 
we'll catalogue the various accounts according to two
main kinds of non-circular strategies that commentators attribute
to Descartes. (The secondary literature offers multiple variations
on each of these main kinds of interpretations, though the
variations won't here be explored. For further alternative 
schemes for cataloguing interpretations, see Hatfield 2006 and
Newman & Nelson 1999. For an anthology devoted largely to the 
Cartesian Circle, see Doney 1987.)



> 
> 
> **Bounded Doubt interpretations**:
> 
> 
> 
> **Arc 1**: The conclusion that an all-perfect God exists
> is derived from premises that are clearly and distinctly perceived
> - *indeed, premises belonging to a special class of truths
> that are fully immune to doubt prior to establishing the general
> veracity of propositions that are clearly and distinctly
> perceived*.
> 
> 
> 
> **Arc 2**: The general veracity of propositions that are
> clearly and distinctly perceived is derived from the conclusion that
> an all-perfect God exists.
> 
> 
> 



Again, the italicized segment marks an addition to the original
statement of Arc 1. Call this a 'Bounded Doubt'
interpretation, because this kind of interpretation construes
hyperbolic doubt as *bounded*. More precisely, the Evil Genius
Doubt is (on this reading) bounded in the sense that its sceptical
potency does not extend to all judgments: a special class of truths is
outside the bounds of doubt. Exemplary of this special class are the
*cogito* and, importantly, the premises of the Third Meditation
proofs of God. Propositions in this special class can be perfectly
known, even by atheists.



On this interpretation, there is no vicious circularity in the broader
argument, because the truths serving as premises in the arguments for
the C&D Rule are perfectly knowable independently of that rule.
That is, throughout the arguments of Arcs 1 and 2, the premises
employed count as perfectly knowledge *prior* to the knowledge
of the C&D Rule they help establish.



Proponents of this interpretation are apt to cite the Third Meditation
passage distinguishing what's *revealed by the natural
light*, and what's *taught by nature* (see
 Section 4.3).
In order to extend perfect knowledge beyond the privileged class of
truths (revealed by the natural light), it is necessary to establish
the general veracity of the C&D Rule. Thus, the need (on this
interpretation) for Arc 2 in the broader project.



The other main kind of interpretation avoids circularity in a
different manner. Let's consider that alternative.



> 
> 
> **Unbounded Doubt interpretations**:
> 
> 
> 
> **Arc 1**: The conclusion that an all-perfect God exists
> is derived from premises that are clearly and distinctly perceived
> - *i.e., premises that are accepted despite being vulnerable
> to Evil Genius Doubt, because our cognitive nature compels us to
> assent to clearly and distinctly perceived propositions*.
> 
> 
> 
> **Arc 2**: The general veracity of propositions that are
> clearly and distinctly perceived is derived from the conclusion that
> an all-perfect God exists.
> 
> 
> 



Again, the italicized segment marks an addition to the original
statement of Arc 1. Let's call this an 'Unbounded
Doubt' interpretation, because this kind of interpretation
construes hyperbolic doubt as *unbounded*. More precisely,
the Evil Genius Doubt is (on this reading) unbounded in the sense
that it undermines *all* manner of judgments - even
the *cogito*, even the premises of the Third Meditation
proofs of God - when the mind is no longer attending to them 
clearly and distinctly. Insofar as the meditator assents to the
steps of these proofs, he does so not because of having an 
understanding of clear and distinct perceptions as being guaranteed 
true, but because the mind *cannot but assent* to them 
*while* attending clearly and distinctly.



Importantly, if doubt is thus unbounded there is no circularity. For,
on this reading of Arc 1, the arguments therein do not presuppose the
general veracity of the C&D Rule. The premises contributing to
the conclusion of an all-perfect God remain vulnerable to hyperbolic
doubt. Throughout this stage of the inquiry, none of the
meditator's judgments based in clear and distinct perception
constitutes perfect knowledge. It is the unboundedness of hyperbolic
doubt that underwrites the No Atheistic Perfect Knowledge Thesis.



A central feature of this interpretation is worth repeating. It
is natural for critics to ask why the arguments of Arc 1 are
*accepted* by the meditator if, indeed, Evil Genius Doubt
remains in play. The answer lies in the *indirect* manner
in which the doubt undermines clear and distinct perception
 (Section 4.3).
*While* clearly and distinctly attending to a proposition,
the mind *cannot but assent*: "my nature is such that
so long as I perceive something very clearly and distinctly I
cannot but believe it to be true." Therefore, *while*
the meditator attends to the steps of the Third Meditation arguments 
for God, he cannot but accept them. However, the meditator does not 
(yet) have perfect knowledge of those premises, nor of their 
conclusions. How, then, do those matters finally rise to the status
of perfect knowledge? We return to this issue, below. At present,
the focus is on the issue of circularity.



Though bounded and unbounded doubt interpretations can both avoid 
vicious circularity, each confronts further difficulties -
both textual and philosophical. Avoiding the charge of vicious 
circularity marks the beginning of the interpreter's work,
not the end. Bounded doubt interpreters must explain why, in the 
*first place*, the Evil Genius Doubt's potency does
not extend to propositions in the special class. Unbounded doubt 
interpreters must explain why, in the *final analysis*,
the Evil Genius Doubt eventually loses it undermining potency. 
Let's consider each of these further problems.



Granting a bounded doubt interpretation, why - in the first
place - does the Evil Genius Doubt's potency not extend
to propositions in the special class? How is it that the doubt
*does* undermine the proposition "that two and three
added together make five," but *not* the proposition
"that there must be at least as much [reality] in the efficient
and total cause as in the effect of that cause"? The first
proposition is included in the list of examples that *are*
undermined by the Evil Genius Doubt (see the fourth paragraph of the
Third Meditation). The second proposition is a premise in a Third
Meditation argument for God - a proposition immune to doubt,
according to bounded doubt interpretations. What is supposed to be
the relevant difference between these propositions? Given the indirect
manner in which Evil Genius Doubt operates, there seems no clear
explanation of why the doubt succeeds in undermining the first
proposition but is somehow resisted by the second. Further awkward for
this interpretation is that the *cogito* is included in the
list of examples that that same fourth paragraph passage implies is
vulnerable to doubt.



Granting an unbounded doubt interpretation, why - in the final
analysis - does the Evil Genius Doubt eventually lose its
undermining potency? Putting the point ironically: Why doesn't
the Evil Genius Doubt undermine the very arguments intended to refute
the Evil Genius Doubt, as soon as the mind is no longer attending to
those premises? Consider Descartes' own explanation of how
hyperbolic doubt undermines the conclusions of arguments once their
premises are no longer in the mind's view:



> 
> There are other truths which are perceived very clearly by our
> intellect so long as we attend to the arguments on which our knowledge
> of them depends; and we are therefore incapable of doubting them
> during this time. But we may forget the arguments in question and
> later remember simply the conclusions which were deduced from them.
> The question will now arise as to whether we possess the same firm and
> immutable conviction concerning these conclusions, when we simply
> recollect that they were previously deduced from quite evident
> principles (our ability to call them 'conclusions'
> presupposes such a recollection). (Replies 2, AT 7:146, CSM 2:104)
> 



So, when we're no longer clearly and distinctly perceiving the
steps of an argument, we do not "possess the same firm and
immutable conviction" of its conclusion. But precisely such
moments are when hyperbolic doubt does its undermining work. This
means that upon diverting attention from the premises of Arcs 1 and
2, it would then be possible to run the Evil Genius Doubt on their conclusions. It would thus seem that unbounded doubt interpretations 
leave us in a Sisyphus-like predicament. According to the myth, each 
time Sisyphus pushes his boulder near to the top of the hill, the 
boulder slips away, rolling to the very bottom, and the whole process 
must start all over. By carefully constructing the arguments of Arcs
1 and 2, the meditator gains anti-sceptical momentum, pushing his 
project near to the goal of perfect knowledge. But each time, once
his attention is diverted from the steps of the arguments, he finds
himself back at the bottom of the hill, wondering about the
credibility of those proofs that had seemed so evident: that is
(as Descartes states the comparable problem, above), the question
now arises "as to whether we possess the same firm and
immutable conviction concerning these conclusions, when we simply
recollect that they were previously deduced from quite evident
principles." As Michael Ayers writes:



> 
> Descartes's enterprise might well look worthless. For even
> if it were granted that his argument is both valid and simple enough
> to be grasped intuitively, as soon as it is no longer so grasped it 
> would seem to fall open to the very same doubt as it refutes. What
> is the value of such a momentary triumph over scepticism? (1998,
> 1013)
> 



Let's turn to an account that purports to solve this problem
arising with unbounded doubt interpretations.



(For examples of bounded doubt interpretations, see Broughton 2002, 
Doney 1955, Della Rocca 2005, Kenny 1968, Morris 1973,
Rickless 2005, and Wilson 1978. For examples of unbounded doubt 
interpretations, see Carriero 2009, Curley 1978 and 1993, DeRose 
1992, Loeb 1992, Newman 2012, Newman & Nelson 1999, Sosa 
1997a and 1997b, and Van Cleve 1979.)


### 6.2 Self-Evident God Interpretation



Again, the hard question for unbounded doubt interpretations: Why,
in the final analysis, does the Evil Genius Doubt eventually lose it
undermining potency? One recent unbounded doubt interpretation (Newman
& Nelson 1999) offers a solution, including an explanation of why
Descartes waits until the end of the Fifth Meditation to claim final
victory over the sceptical problem. Here is a sketch of the
account.



Descartes claims that his final solution to the sceptical problem
makes it "impossible for us ever to have any reason for
doubting what we are convinced of." Yet how is this 
*impossibility* supposed to be achieved? We have seen
that the sticking point in the account is *indirect* doubt. 
Descartes rejects that we could overcome the problem via
uninterrupted clear and distinct perception: "my nature is
also such that I cannot fix my mental vision continually on the
same thing, so as to keep perceiving it clearly; and often the
memory of a previously made judgement may come back, when I am
no longer attending to the arguments which led me to make it."
At such moments of inattention, an indirect doubt remains possible
so long as we can make sense of the evil genius scenario, or any
other scenario wherein we have a defective cognitive nature. It
thus seems that a final solution to the problem would need (somehow)
to make it no longer possible to make sense of the relevant sceptical 
scenarios. Indeed, the proposed interpretation has it the sceptical 
scenarios become self-evidently incoherent. We come to have an
utterly basic apprehension that we're the creation of an
all-perfect creator who would not allow us to be deceived about
what we clearly and distinctly perceive.



The needed apprehension of God would have to be *self-evident*. 
For suppose my apprehension is grounded in a demonstration. In that 
case, it's possible to think of the conclusion of that 
demonstration without also thinking of the premises; and on such 
occasions, my confidence in the demonstration is vulnerable to an 
indirect doubt. Thus, the needed apprehension of God is a self-evident, 
clear and distinct conception that renders - as literally 
unthinkable - the very sceptical scenarios that underwrite 
indirect doubt.



A useful analogy lies in the doubt-resisting character of the
*cogito*. If I attempt a *direct* doubt of own my
existence, the effort is self-stultifying; I immediately apprehend
that I must exist, in order to attempt the doubt. What Descartes
needs is a similarly strong and immediate doubt-resisting outcome
in connection with *the very attempt* at running an indirect 
doubt. That is, on occasions of trying to undermine clearly and 
distinctly perceived matters - e.g., by doubting God's 
existence, or benevolence, or the like - the very effort at
doubt would be immediately thwarted.



Multiple texts suggest that this is the account Descartes intends,
and that the Fifth Meditation is the locus of the meditator's
discovery of an enhanced, self-evident apprehension of God. The
Fifth Meditation introduces various themes about innate truths, 
including the positive epistemic effects of repeated meditation:
truths initially noticed only by means of inference might eventually 
come to be apprehended self-evidently. In the build-up to the
passage claiming that the Evil Genius Doubt is finally and fully 
overcome, Descartes writes:



> 
> Some of the things I clearly and distinctly perceive are obvious to
> everyone, while others are discovered only by those who look more
> closely and investigate more carefully; but once they have been
> discovered, the latter are judged to be just as certain as the former.
> In the case of a right-angled triangle, for example, the fact that the
> square on the hypotenuse is equal to the square on the other two sides
> is not so readily apparent as the fact that the hypotenuse subtends
> the largest angle; but once one has seen it, one believes it just as
> strongly. But as regards God, if I were not overwhelmed by
> preconceived opinions, and if the images of things perceived by the
> senses did not besiege my thought on every side, I would certainly
> acknowledge him sooner and more easily than anything else. For what is
> more self-evident [*ex se est apertius*] than the fact that the
> supreme being exists, or that God, to whose essence alone existence
> belongs, exists?
> 
> 
> Although it needed close attention for me to
> perceive this, I am now just as certain of it as I am of everything
> else which appears most certain. And what is more, I see that the
> certainty of all other things depends on this, so that without it
> nothing can ever be perfectly known. (AT 7:69, CSM 2:47f)
> 
> 
> 



Descartes reiterates the theme in the Second Replies:



> 
> I ask my readers to spend a great deal of time and effort on
> contemplating the nature of the supremely perfect being. Above all
> they should reflect on the fact that the ideas of all other natures
> contain possible existence, whereas the idea of God contains not only
> possible but wholly necessary existence. This alone, without a formal
> argument, will make them realize that God exists; and this will
> eventually be just as self-evident [*per se notum*] to them as
> the fact that the number two is even or that three is odd, and so on.
> For there are certain truths which some people find self-evident,
> while others come to understand them only by means of a formal
> argument. (AT 7:163f, CSM 2:115)
> 



These passages convey that one's apprehension of God eventually
upgrades from being inferential, to being transparently self-evident.
Granting that the meditator has achieved an apprehension of God of
this kind, it plausibly explains why Descartes would think he's
achieved a final solution to the sceptical problem. Given his newfound
epistemic standing, the meditator would be unable to make coherent
sense of the Evil Genius Doubt. His clear and distinct perceptions
would be fully indubitable, thereby counting as perfect knowledge.



The interpretation helps explain two passages wherein Descartes
purports to be detailing the final solution to the sceptical problem.
In both passages, he can seem simply to be *asserting* that
sceptical doubts are impossible, as if having forgotten the
*indirect* manner in which his own hyperbolic doubt operates.
But if we take Descartes to be assuming that the apprehension of God
has become utterly self-evident, both passages make more sense. The
one passage arises in the Second Replies, in the context of rebutting
an objection to the effect that, in the final analysis, it remains
possible to doubt clear and distinct perception. Descartes replies
that the objector is "still stuck fast" in doubts
"put forward in the First Meditation," but "very
carefully removed in the succeeding Meditations," adding:



> 
> [O]nce we have become aware that God exists it is necessary for us to
> imagine that he is a deceiver if we wish to cast doubt on what we
> clearly and distinctly perceive. And since *it is impossible to
> imagine that he is a deceiver*, whatever we clearly and distinctly
> perceive must be completely accepted as true and certain. (AT 7:144,
> CSM 2:103; italics added)
> 



The other passage arises in the Fifth Meditation, in the concluding
summary explanation of how the sceptical problem is finally overcome.
Importantly, on the present interpretation, is the context in which
the summary explanation occurs: namely, on the heels of revealing the
newly discovered thesis, that nothing "is more self-evident than
the fact that the supreme being exists." In that context,
Descartes explains that a final solution to the sceptical problem has
been achieved.



> 
> Now, however, I have perceived that God exists, and at the same time I
> have understood that everything else depends on him, and that he is no
> deceiver; and I have drawn the conclusion that everything which I
> clearly and distinctly perceive is of necessity true. Accordingly,
> even if I am no longer attending to the arguments which led me to
> judge that this is true, as long as I remember that I clearly and
> distinctly perceived it, there are no counter-arguments which can be
> adduced to make me doubt it, but on the contrary I have true and
> certain knowledge of it. And I have knowledge not just of this matter,
> but of all matters which I remember ever having demonstrated, in
> geometry and so on. For what objections can now be raised? That the
> way I am made makes me prone to frequent error? But I now know that I
> am incapable of error in those cases where my understanding is
> transparently clear. Or can it be objected that I have in the past
> regarded as true and certain many things which I afterwards recognized
> to be false? But none of these were things which I clearly and
> distinctly perceived: I was ignorant of this rule for establishing the
> truth, and believed these things for other reasons which I later
> discovered to be less reliable. So what is left to say? (AT 7:70, CSM
> 2:48f)
> 



Absent a self-evident apprehension of God, the two passages appear
inexplicable, with Descartes seeming to misunderstand the sceptical
implications of his own Evil Genius Doubt. But on the self-evident God
interpretation, both passages read as a summary of the anti-sceptical
effects of it being impossible to conceive of God as a deceiver. As
Descartes writes to Voetius, the very thought of God as a deceiver
"implies a conceptual contradiction - that is, it cannot
be conceived" (May 1643 letter, AT 8b:60, CSMK 222). The
interpretation also makes sense of why the final victory over
scepticism is announced not at the end of the Fourth Meditation, but
at the end the Fifth - i.e., after the enhanced, self-evident 
apprehension of God is supposed to have been achieved.



(For further discussion see Newman & Nelson 1999, Nolan 2005,
and Nolan &and Nelson 2006.)


### 6.3 Another Cartesian Circle?



Michael Della Rocca has recently argued that a further circle arises
from considerations in the Fourth Meditation - a problem he
suspects is "more difficult to get out of than the traditional
problem of circularity" (2011, 98). To help clarify this further
circle, Della Rocca focuses on a twofold question:



> 
> Why, for Descartes, should we not assent to ideas that are not clear
> and distinct and why is there no such obligation not to assent to
> clear and distinct ideas? The reason Descartes offers seems to be that
> we should not assent to ideas that are not clear and distinct because
> they, unlike clear and distinct ideas, are not guaranteed to be true.
> (2011, 96)
> 



As Della Rocca understands the broader Fourth Meditation argument, the
claim that we should assent only to what we clearly and distinctly
perceive is an essential step in the ongoing argument to establish the
divine guarantee of clear and distinct perception. Since this step
presupposes the eventual conclusion, that conclusion is based on
circular reasoning:



> 
> One of the premises needed for arguing that clear and distinct ideas
> are true is, as we have seen, that we should assent only to clear and
> distinct ideas. This claim, in turn, requires argument, and the
> argument for it seems to be based on the claim that clear and distinct
> ideas are guaranteed to be true. So, one of the premises of the
> argument for the claim that clear and distinct ideas are true is that
> clear and distinct ideas are guaranteed to be true. Here, the
> conclusion - indeed, a strengthened version of the conclusion
> - is itself a premise in the argument. (2011, 98)
> 



Perhaps we can avoid this alleged circle. The linchpin of Della
Rocca's charge of circularity is his contention that
"Descartes's reason for saying that we should assent only
to clear and distinct ideas is that such ideas are guaranteed to be
true and ideas that are not clear and distinct are not guaranteed to
be true" (2011, 97). Though Descartes can be read in this way,
the texts support the following alternative understanding of the
broader argumentative narrative. In the First Meditation, the
meditator initially resolves that he should withhold assent to
anything which is "not completely certain and indubitable"
(AT 7:18, CSM 2:12). Early in the Third Meditation, having reflected
on the epistemic impressiveness of the *cogito*, the meditator
discovers that *all*, but *only*, clear and distinct
perceptions are utterly assent-compelling. As a practical consequence,
his initial resolve effectively implies that he should assent only to
clear and distinct perceptions - not because of presupposing the
conclusion of the eventual proof of the C&D Rule, but because
these are the only perceptions to which he *can't but*
assent. This provides a practical answer to Della Rocca's
question, concerning why we should "not assent to ideas that are
not clear and distinct and why is there no such obligation not to
assent to clear and distinct ideas." It is in the Fourth
Meditation that the meditator purports to demonstrate the divine
guarantee of the C&D Rule. However, no step of that demonstration
presupposes that clear and distinct perceptions have already been
established as true; i.e., the conclusion of the demonstration is not,
as Della Rocca contends, "based on the claim that clear and
distinct ideas are guaranteed to be true." Rather (as we saw in
 Section 5.3),
 the conclusion purports to be based on an analysis of the respective
contributions of the intellect and the will, to judgment formation.
Summarizing the key steps:



> 
> So what then is the source of my mistakes? It must be simply this: the
> scope of the will is wider than that of the intellect; but instead of
> restricting it within the same limits, I extend its use to matters
> which I do not understand. (AT 7:58, CSM 2:40)
> 



Granted, the meditator needs each of the demonstrative steps to be
clearly and distinctly perceived. However, he needs this not because
of presupposing the conclusion to be proved, but in order to be in
compliance with his own initial resolve, stated in the First
Meditation - to withhold assent to anything which is
"not completely certain and indubitable."



Central to the above account avoiding Della Rocca's circle is
(among other claims) the thesis that clear and distinct perceptions
are assent-compelling - i.e., as Descartes writes, that
"the nature of my mind is such that I cannot but assent to these
things, at least so long as I clearly perceive them." It it thus
worth noting that Della Rocca wavers on whether Descartes holds this
thesis: he interprets a remark in Descartes' correspondence (9
Feb 1645, AT 4:173, CSMK 245) to suggest "that we can withhold
assent from even a current clear and distinct perception" (2006,
155).


### 6.4 Is *Truth* a Condition of Perfect Knowledge?



We noted in
 Section 1.1
 that Descartes' clearest statements appear to indicate a
*justified belief* analysis of perfect knowledge. Consider
again the relevant Second Replies passage:



> 
> Hence you see that once we have become aware that
> God exists it is necessary for us to imagine that he is a deceiver if
> we wish to cast doubt on what we clearly and distinctly perceive. And
> since it is impossible to imagine that he is a deceiver, whatever we
> clearly and distinctly perceive must be completely accepted as true
> and certain.
> 
> 
> But since I see that you are still stuck fast in
> the doubts which I put forward in the First Meditation, and which I
> thought I had very carefully removed in the succeeding Meditations, I
> shall now expound for a second time the basis on which it seems to me
> that all human certainty can be founded.
> 
> 
> First of all, as soon as we think that we
> correctly perceive something, we are spontaneously convinced that it
> is true. Now if this conviction is so firm that it is impossible for
> us ever to have any reason for doubting what we are convinced of, then
> there are no further questions for us to ask: we have everything that
> we could reasonably want. What is it to us that someone may make out
> that the perception whose truth we are so firmly convinced of may
> appear false to God or an angel, so that it is, absolutely speaking,
> false? Why should this alleged "absolute falsity" bother
> us, since we neither believe in it nor have even the smallest
> suspicion of it? For the supposition which we are making here is of a
> conviction so firm that it is quite incapable of being destroyed; and
> such a conviction is clearly the same as the most perfect certainty.
> (AT 7:144f, CSM 2:103)
> 
> 
> 



The last part of the passage emphasizes two conditions: a belief
condition, expressed in terms of *conviction*, and a
justification condition, expressed in terms of *indubitability*
or unshakability - "conviction based on a reason so strong
that it can never be shaken by any stronger reason."
Conspicuously missing is any further condition stipulating that
the conviction must be *true*. The passage does clarify,
of anything that would count as perfect knowledge, that it is
"completely accepted as true"; that we are
"convinced that it is true," indeed, that we are
"firmly convinced." But these remarks speak to the
belief condition, not to an expressed *truth* condition. 
Indeed, the passage is plausibly read even more strongly: i.e.,
not merely as omitting mention of a truth condition, but as
allowing for some broad possibility that what *we* regard
as indubitable truths are, "absolutely speaking, 
false."



Why, then, is Descartes dismissive of the stated objection, indicating
that it shouldn't "bother" us? On one plausible 
reading of the passage, Descartes is assuming that the 
*possibility* in question is simply a further iteration of
Evil Genius Doubt - "I see that you are still stuck fast
in the doubts which I put forward in the First Meditation." 
Whether a deceiving God is *really* possible, it's 
something Descartes has argued to be unimaginable for perfect
knowers, i.e., for successful graduates of the *Meditations* 
- "it is impossible to imagine that he [God] is a 
deceiver." On a plausible reading, therefore, Descartes is 
dismissive of the objection not on metaphysical grounds of absolute 
impossibility, but on epistemic grounds of *indubitability*:
the "alleged 'absolute falsity'," noted in
the objection, should in no way "bother us" because our 
conviction is "so firm that it is quite incapable of being 
destroyed."



Why does Descartes not add a truth condition, thereby ensuring that
beliefs counting as perfect knowledge are *true*? In an 
influential 1970 book, Harry Frankfurt offers a provocative answer.
He argues that Descartes' goal, truth-wise, is to establish
the consistency of our beliefs, but not their correspondence with
an external reality. Writes Frankfurt:



> 
> The point of Descartes's validation of reason is that if reason
> is properly employed - that is, if we give assent only to what
> we clearly and distinctly perceive - we are not led to doubt
> that reason is reliable. ... The crux of Descartes's
> validation of reason is not so much the discovery that a benign deity
> exists, but that reason leads to the conclusion that such a deity
> exists. (1970, 176)
> 



Frankfurt thinks that Descartes' novel plan involves arguing
that our best rational efforts show that our best rational efforts are
logically consistent: it is "an attempt to show that there are
no good reasons for believing that reason is unreliable - that
the mistrust of reason is not supported by reason and that it is
accordingly irrational" (1970, 175). Frankfurt adds that
"the conception of truth involved in [Descartes'] question
about the truth of what is clearly and distinctly perceived is, in
other words, a conception of *coherence* rather than of
*correspondence*" (1970, 170).



Frankfurt's coherentist interpretation is at odds with a number
of textual and doctrinal considerations. Descartes writes to Mersenne
that "the word 'truth', in the strict sense, denotes
the conformity of thought with its object" (16 Oct 1639, AT
2:597, CSMK 139). The suggestion here is of some version of a
correspondence theory. Also, on the most straightforward reading of
the epistemic moves in the *Meditations*, Descartes is
presupposing that at least some truths involve extramental
metaphysical relations. Consider that Evil Genius Doubt is,
fundamentally, a worry not about whether our various clear and
distinct judgments *cohere*, but about whether they accurately
represent an extramental reality - i.e., a doubt about
"whether things do in reality correspond to our perception of
them" (Replies 4, AT 7:226, CSM 2:159). Interestingly, Frankfurt
himself came to renounce the interpretation:



> 
> I now think, however, that it was a mistake on my part to suggest that
> Descartes entertained a coherence conception of truth. The fact is
> that there is no textual evidence to support that suggestion; on the
> contrary, whenever Descartes gives an explicit account of truth he
> explains it unequivocally as correspondence with reality. (1978, 36f)
> 



How then should we interpret the Second Replies passage, and how
should we understand the absence of a truth condition? I suggest that
the lack of a truth condition need not reflect an indifference about
truth, as opposed to a view about how a concern for truth is properly
expressed in an account of knowledge. We can understand Descartes as
wanting a *fully* internalist account whereby *all*
conditions of knowledge are accessible to the would-be knower. Putting
the point another way, if the question of *whether* the
conditions of knowledge had been met were answerable only by
"God or an angel," it would impose an unacceptably
*externalist* element on the theory. On a *justified
belief* rendering, his account of perfect knowledge *is*
fully internalist; yet, with the addition of a truth condition, it is
*not* - at least, not given a correspondence theory of
truth, in the context of metaphysical realism. Importantly, then, in
attributing to Descartes a justified belief account, we need not
thereby attribute to him an *indifference* concerning truth.
Rather, we can attribute to him the view that the way properly to
express one's concern for truth is by enforcing high
justificatory standards. Again, from that same passage:



> 
> Now if this conviction is so firm that it is impossible for us ever to
> have any reason for doubting what we are convinced of, then there are
> no further questions for us to ask: we have everything that we could
> reasonably want.
> 



One possible objection to a justified belief account is expressed by
Lennon, who worries that on such accounts the desired cognitive state
(indubitability) "could as well be achieved by a pill";
adding that "Descartes would not be satisfied with such a pill
because his aim is not just to arrive at certainty, but truth, which
he cannot help but think he has achieved" (2008, 167). (Cf.
Hatfield 2006, 135, who expresses a related objection.)



Granted, if the pill simply prevented me from apprehending any reasons
for doubting my beliefs, we'd be loath to regard such beliefs as
knowledge. Descartes himself makes a related point in connection with
an atheist geometer who happens never to doubt his beliefs, simply
because the Evil Genius Doubt never occurs to him:



> 
> [A]lthough this doubt may not occur to him, it can still crop up if
> someone else raises the point or if he looks into the matter himself.
> So he will never be free of this doubt until he acknowledges that God
> exists. (Replies 2, AT 7:141, CSM 2:101)
> 



Presumably, Descartes' point holds whether the doubt simply
never occurs to him, or is instead prevented from occurring by a
pill. Note further that the spirit of the objection presupposes that 
the achieved indubitability is merely psychological, in that 
the person simply runs up against an *inexplicable* inability
to doubt. Yet we have seen clear texts which have Descartes 
characterizing the desired states of clarity and distinctness not 
merely psychologically, but, further, in epistemic terms implying a 
sort of *cognitive luminance*, or *rational insight*.
He uses light metaphors including the association of clarity and 
distinctness with the *natural light*. The meditator's 
ability to ward off the evil demon - during occurrent clarity
and distinctness - is described in terms of perceiving 
"utterly clearly with [the] mind's eye"; and of
being "convinced" of all matters the denial of which
leads one to "see a manifest contradiction" (Med. 3,
AT 7:36, CSM 2:25). In Descartes' view, our inability to doubt 
the matters we clearly and distinctly perceive is not simply a causal 
result, but also a rational result of what such perception enables
us to understand. Were there a pill that would induce both the
causal and the rational outcomes that Descartes associates with
perfect knowledge, then, arguably, he would endorse taking the pill. 
For we would then "have everything that we could reasonably 
want."



Another possible objection is that Descartes' high justificatory
standards generate a *de facto* truth condition: because having
Cartesian certainty *entails* that one's beliefs are
true, truth is a necessary condition of knowledge. But this objection
misses a key point. As suggested in the Second Replies passage,
Cartesian certainty - understood in terms of
*indubitability* - does not, strictly speaking, rule out
the broad possibility that we are in error. The notions of
*indubitability* and *truth* are different: that
"*p* is indubitable" entails not that
"*p* is true," but that "there can be no
reasons for doubting *p*." Descartes' final
solution to the Evil Genius Doubt entails not that an evil genius
cannot *be*, but that it cannot be *coherently
conceived*. And that it cannot be coherently conceived, thinks
Descartes, gives us "everything that we could reasonably
want" - not because such coherence is the goal, but
because of what it *establishes*, truth-wise.



(For further discussion of the role of truth in perfect knowledge, see
Frankfurt 1970 and 1978, Hatfield 2006, Lennon 2008, Loeb
1992, and Newman & Nelson 1999.)


## 7. Proving an External Material World



The opening line of the Sixth Meditation makes clear its principal
objective: "It remains for me to examine whether material things
exist" (AT 7:71, CSM 2:50). At this juncture, the meditator
perfectly knows of his own existence and of God's. It follows
that there's an external world with at least one object, namely,
God. However, the existence of an external *material* world
remains in doubt. Establishing the existence of material bodies is not
a straightforward matter of perceiving them, because, in
Descartes' view, "bodies are not strictly perceived by the
senses" (see
 Section 9.1).



In his eventual argument, Descartes' strategy for proving an
external material world has two main parts: first, he argues for the
*externality* of the causes of sensation; second, he argues for
the *materiality* of these external causes. (Calling the ideas
in question "sensations" can seem circular, if one
conceives of sensations as having a physiological component. But note
that for Descartes, "what is called 'having a sensory
perception'," strictly encompasses only a mental aspect
Med. 2, AT 7:29, CSM 2:19). From these two steps, it follows that there
exists an external material world. Let's consider each phase of
the argument.


### 7.1 Case for the *Externality*
of the Causes of Sensation



Descartes builds on a familiar line of argument in the history of
philosophy, itself appealing to the involuntariness of sensations.
The familiar argument is first articulated in the Third Meditation.
Speaking of his apparently adventitious ideas (sensations), the
meditator remarks:



> 
> But the chief question at this point concerns the ideas which I take
> to be derived from things existing outside me ... I know by
> experience that these ideas do not depend on my will, and hence that
> they do not depend simply on me. Frequently I notice them even when I
> do not want to: now, for example, I feel the heat whether I want to or
> not, and this is why I think that this sensation or idea of heat comes
> to me from something other than myself, namely the heat of the fire by
> which I am sitting. (AT 7:38, CSM 2:26)
> 



Though some such involuntariness argument has convinced many
philosophers, the inference does not hold up to methodical doubt, as
the meditator explains:



> 
> Then again, although these [apparently adventitious] ideas do not
> depend on my will, it does not follow that they must come from things
> located outside me. Just as the impulses which I was speaking of a
> moment ago seem opposed to my will even though they are within me, so
> there may be some other faculty [of my mind] not yet fully known to
> me, which produces these ideas without any assistance from external
> things; this is, after all, just how I have always thought ideas are
> produced in me when I am dreaming. (Med. 3, AT 7:39, CSM 2:27)
> 



We first examined this passage in regard to the Always Dreaming Doubt.
That sceptical hypothesis raises the problem of the existence of
external things. For all I know, my "waking" experiences 
are produced not by external things, but by processes similar to those
producing my dreams. This sceptical possibility explains why the
familiar involuntariness argument fails: the inference presupposes
exactly what is at issue - namely, whether involuntarily
received sensory ideas are produced by external things, rather than
by a subconscious faculty of my mind.



Many philosophers have assumed that we lack the epistemic resources to
solve this sceptical problem. For example, Hume writes:



> 
> By what argument can it be proved, that the perceptions of the mind
> must be caused by external objects ... and could not arise either
> from the energy of the mind itself ... or from some other cause
> still more unknown to us? It is acknowledged, that, in fact, many of
> these perceptions arise not from anything external, as in dreams,
> madness, and other diseases. ... It is a question of fact,
> whether the perceptions of the senses be produced by external objects
> ... But here experience is, and must be entirely silent.
> (*Enquiry* Sec. 12)
> 



Interestingly, Descartes would agree that *experiential*
resources cannot solve the problem. By the Sixth Meditation, however,
Descartes purports to have the *innate* resources he needs to
solve it - notably, innate ideas of mind and body. Among the
metaphysical theses he develops is that mind and body have wholly
distinct essences: the essence of thinking substance is pure thought;
the essence of body is pure extension. In a remarkable maneuver,
Descartes invokes this distinction to refute the sceptical worry that
sensations are produced by a subconscious faculty of the mind:
"nothing can be in me, that is to say, in my mind, of which I am
not aware," and this "follows from the fact that the soul
is distinct from the body and that its essence is to think" (13
Dec 1640 letter to Mersenne, AT 3:273, CSMK 165f). This result allows
Descartes to supplement the involuntariness argument, thereby
strengthening the inference. For from the additional premise that
*nothing can be in my mind of which I am unaware*, it follows
that if sensations were being produced by some activity in my mind,
I'd be aware of that activity on the occasion of its operation.
Since I'm not thus aware, it follows that the sensation
I'm having is produced by a cause external to my mind. As
Descartes writes, this cause



> 
> ... cannot be in me, since clearly it presupposes no intellectual
> act [of awareness] on my part, and the ideas in question are produced
> without my cooperation and often even against my will. So the only
> alternative is that it is in another substance distinct from me
> ... (Med. 6, AT 7:79, CSM 2:55)
> 



It follows that my sensations are caused by external world objects
- i.e., objects external to my mind. It remains to be shown that
these external causes are *material* objects.


### 7.2 Case for the *Materiality*
of the Causes of Sensation



On Descartes' analysis, there are three possible options for the
kind of external thing causing sensations:


1. God
2. Material/corporeal substance
3. Some other created substance



That is, the cause is either infinite substance (God), or finite
substance; and if finite, then either corporeal, or something else.
Descartes thinks he eliminates options (a) and (c) by appeal to God
being no deceiver:



> 
> But since God is not a deceiver, it is quite clear that he does not
> transmit the ideas to me either directly from himself, or indirectly,
> via some creature [other than corporeal substance] ... For God
> has given me *no faculty at all for recognizing any such*
> source for these ideas; on the contrary, he has given me *a great
> propensity to believe* that they are produced by corporeal things.
> It follows that corporeal things exist. (Med. 6, AT 7:79f, CSM 2:55;
> italics added)
> 



This is a problematic passage. The "great propensity"
here cited is not the irresistible compulsion of clear and distinct
perception. (If it were, the conclusion that sensation is caused by
material objects would follow straightaway from this clear and
distinct perception, via the C&D Rule.) But unless each step of
the argument is clearly and distinctly perceived, Descartes should not
be making the argument. Adding to the difficulties of the passage, he
expressly cites the conclusion as following from the fact that
"God is not a deceiver," implying that he thinks this
inference is supported by a divine guarantee.



On one kind of interpretation, Descartes relaxes his epistemic
standards in the Sixth Meditation (cf. Schmitt 1986, 493f). He no
longer insists on perfect knowledge, now settling for probabilistic
arguments. Though no decisive texts support the interpretation, it
does find some support. For instance, in the Synopsis to the
*Meditations*, Descartes writes of his Sixth Meditation
arguments:



> 
> The great benefit of these arguments is not, in my view, that they
> prove what they establish ... The point is that in considering
> these arguments we come to realize that they are not as solid or as
> transparent as the arguments which lead us to knowledge of our own
> minds and of God ... (AT 7:15f, CSM 2:11)
> 



The remark can be read as a concession that the Sixth Meditation
arguments are weaker than the earlier arguments about minds and God
- that these later arguments do not "prove what they
establish." Of course, one need not read the remark this way.
And other texts are unfavorable to this interpretation. For example,
in the opening paragraphs of the Sixth Meditation, Descartes considers
a probabilistic argument for the existence of external bodies. Though
he accepts the proposed account as offering the best explanation, he
nonetheless dismisses it for the express reason that it grounds
"only a probability" - it does not provide the
"basis for a necessary inference that some body exists"
(AT 7:73, CSM 2:51). This is a puzzling dismissal, assuming Descartes
has relaxed his standards to probable inference.



The relaxed standards interpretation falls short for another reason.
It leaves unexplained why Descartes cites a divine guarantee for the
conclusion that sensations are caused by material objects.



On another kind of interpretation, the troubling passage appealing to
a "great propensity" does not mark a relaxing of epistemic
standards. Instead, Descartes is extending the implications of his
discussion of theodicy in the Fourth Meditation to encompass further
cases of natural belief - such beliefs deriving from our
God-given cognitive nature. It was noted above
 (Section 5.2)
 that Descartes thinks the divine guarantee of the C&D Rule
follows, in part, from the fact that God wouldn't allow us to be
mistaken when our assent is a natural consequence of our God-given
cognitive nature. Suppose Descartes holds that there are further cases
in which an all-perfect God would not allow us to be in error, in part
because the beliefs in question *arise naturally from our God-given
cognitive nature*. And suppose the further cases involve a
*natural propensity* to believe which *cannot be
corrected* by our cognitive faculties. Given these assumptions,
the resulting *rule* for truth would look something like the
following:



> 
> I am not in error in cases in which (i) I have a natural propensity to
> believe, and (ii) God provided me no faculty by which to correct a
> false such belief.
> 



This *rule* is more expansive than the C&D Rule, in that it
licenses more kinds of judgments. Clauses (i) and (ii) are tailored to
the problematic passage wherein, as we've seen, Descartes
invokes two conditions: "God has given me *no faculty at all
for recognizing any such* source for these ideas; on the contrary,
he has given me *a great propensity to believe* that they are
produced by corporeal things." If this is on the right
interpretive track, then Descartes needs some way to justify this
rule. Assuming a proof similar in structure to the proof of the
C&D Rule, the justification might run as follows:


1. There is an all-perfect God.
2. An all-perfect God cannot allow me to be in error in cases in
which (i) I have a natural propensity to believe, and (ii) God
provided me no faculty by which to correct a false such belief.
3. Therefore, I am not in error in cases in which (i) I have a
natural propensity to believe, and (ii) God provided me no faculty
by which to correct a false such belief.



If Descartes affirms premise 2, it explains why he thinks he's
entitled to this more expansive rule, and without relaxing his
epistemic standards. Indeed, a number of texts indicate that he
holds some version of premise 2. The relevant Sixth Meditation
passage states that from "the very fact that God is not a 
deceiver" there is a "consequent impossibility of there 
being any falsity in my opinions which cannot be corrected by some 
other faculty supplied by God" (AT 7:80, CSM 2:55f). Another 
passage adds that we would be "doing God an injustice"
if we implied "that God had endowed us with such an imperfect 
nature that even the proper use of our powers of reasoning allowed
us to go wrong" (*Prin*. 3:43, AT 8a:99, CSM 1:255).
And in the Second Replies, Descartes addresses case of judgments
that "could not be corrected by any clearer judgements or by 
means of any other natural faculty," adding that "in
such cases I simply assert that it is impossible for us to be 
deceived" (Replies 2, AT 7:143f, CSM 2:102f). These passages
make a strong case that something like premise 2 is in play,
indeed implying that God's benevolent nature entails a more
expansive rule of truth than the C&D Rule. (As will emerge,
Descartes looks again to call on this more expansive *rule*
in his effort to prove that he is not dreaming.)



Earlier, we noted another apparent problem in the Sixth Meditation
passage wherein Descartes concludes that the external cause of
sensation is something corporeal. One of his premises cites a
*great propensity* to believe, yet the propensity is not
itself the irresistible compulsion of clear and distinct perception. 
Does not the methodic procedure of the *Meditations* restrict 
Descartes to using clear and distinct premises? By way of reply, 
distinguish (a) that my sensation has an external cause, and (b)
that *I have a great propensity to believe* my sensation has
an external cause. In context, the meditator lacks clear and distinct 
perception of (a). However, the relevant premise of the argument (as 
opposed to its conclusion) is not (a), but (b). And there is no 
principled reason that the meditator cannot clearly and distinctly 
perceive this premise.



A final observation. It goes regularly unnoticed that the conclusion
of Descartes' argument for the existence of an external material
world leaves significant scepticism in place. Granting the success of
the argument, my sensations are caused by an external material world.
But for all the argument shows - for all the broader argument of
the *Meditations* shows, up to this point - my mind might
be joined to a *brain in a vat*, rather than a full human body.
This isn't an oversight on Descartes' part. It's all
he thinks the argument *can* prove. For even at this late stage
of the project, the meditator has not yet established himself to be
awake - a line of inquiry to which we now turn.



(For further discussion of Descartes' effort to prove the
existence of an external material world, see Carriero 2009 [146ff],
Friedman 1997, Garber 1992, and Newman 1994.)


## 8. Perfect Knowledge of Being Awake



By design, the constructive arguments of the *Meditations*
unfold even though the meditator remains in doubt about being awake.
This of course reinforces the ongoing theme that perfect knowledge
does not properly encompass judgments of external sense. (The judgment
that an external material world exists is not strictly a judgment of
external sense - as if knowing its existence simply by sensing
it. Rather, as we've seen, the judgment arises from an complex
inference about the possible causes of sensations.) In the closing
paragraph of the Sixth Meditation, Descartes revisits the issue of
dreaming. He claims to show how, in principle - even if not
easily in practice - it is possible to achieve perfect knowledge
that one is presently awake.



A casual reading of that final paragraph might suggest that Descartes
offers a *naturalistic* solution to the problem (i.e., a
non-theistic solution), in the form of a continuity test: since
continuity with past experiences holds only of waking but not
dreaming, checking for the requisite continuity provides a test for
ascertaining that one is awake. The following remarks can be read in
this way:



> 
> I now notice that there is a vast difference between the two
> ["being asleep and being awake"], in that dreams are never
> linked by memory with all the other actions of life as waking
> experiences are. ... But when I distinctly see where things come
> from and where and when they come to me, and when I can connect my
> perceptions of them with the whole of the rest of my life without a
> break, then I am quite certain that when I encounter these things I am
> not asleep but awake. (AT 7:89f, CSM 2:61f)
> 



This naturalistic "solution" prompts two obvious
criticisms, both raised by Hobbes in the Third Objections. First, the
solution runs contrary to Descartes' No Atheistic Perfect
Knowledge Thesis: since the continuity test (on the naturalistic
reading of it) does not invoke God, it thus appears, as Hobbes notes,
"that someone *can* know he is awake without knowledge of
the true God" (AT 7:196, CSM 2:137). Second, it seems that one
could *dream* the requisite continuity: one could "dream
that his dream fits in with his ideas of a long series of past
events," thus undermining the credibility of the continuity test
(AT 7:195, CSM 2:137).



Mirroring our discussion in
 Section 7.2,
 one kind of interpretation has Descartes relaxing his epistemic
standards. He's aware that the naturalistic solution does not
stand up to methodic doubt, but he's not attempting to overcome
the Now Dreaming Doubt with perfect knowledge. A problem for this
interpretation is that it doesn't square with the following
reply Descartes makes to Hobbes' first objection: "an
atheist can infer that he is awake on the basis of memory of his past
life" (via the continuity test); but "he cannot know that
this criterion is sufficient to give him the certainty that he is not
mistaken, if he does not know that he was created by a non-deceiving
God" (Replies 3, AT 7:196, CSM 2:137). Evidently,
Descartes' solution is not supposed to be available to the
atheist. Taken at face value, this reply rules out a relaxed standards
interpretation; it indeed rules out any interpretation involving a
naturalistic solution to the problem of dreaming.



On closer inspection, the Sixth Meditation passage puts forward not a
naturalistic solution, but a *theistic* one. The meditator
finally concludes that he's awake because, as the passage
explicitly reads, "God is not a deceiver" (AT 7:90, CSM
2:62).



How does his argument go? Recall, in the proof of the external
material world
 (Section 7.2),
 that Descartes mysteriously invokes the following (divinely
guaranteed) truth rule:



> 
> I am not in error in cases in which (i) I have a natural propensity to
> believe, and (ii) God provided me no faculty by which to correct a
> false such belief.
> 



The dreaming passage looks to have Descartes again invoking this rule.
The passage opens with the meditator observing the following:



> 
> I can almost always make use of more than one sense to investigate the
> same thing; and in addition, I can use both my memory, which connects
> present experiences with preceding ones, and my intellect, which has
> by now examined all the causes of error. Accordingly, I should not
> have any further fears about the falsity of what my senses tell me
> every day; on the contrary, the exaggerated doubts of the last few
> days should be dismissed as laughable. This applies especially to
> ... my inability to distinguish between being asleep and being
> awake. (AT 7:89, CSM 2:61)
> 



Referring to the worry that he's presently dreaming as
*exaggerated* suggests that condition (i) is met - i.e.,
suggesting that the present circumstance includes a "natural
propensity" to believe he's awake. As such, he needs only
to establish condition (ii), and he'll have a divine guarantee
of being awake. Here, notice that an important theme of the above
passage concerns the meditator's *faculties for correcting
sensory error* - a theme suggestive of condition (ii). In
context, Descartes' appeal to the continuity test is perhaps
best understood in conjunction with condition (ii). As the meditator
says (speaking of his apparently waking experience):



> 
> [W]hen I distinctly see where things come from and where and when they
> come to me, and when I can connect my perceptions of them with the
> whole of the rest of my life without a break, then I am quite certain
> that when I encounter these things I am not asleep but awake. And I
> ought not to have even the slightest doubt of their reality if,
> *after calling upon all the senses as well as my memory and my
> intellect in order to check them, I receive no conflicting reports
> from any of these sources*. For *from the fact that God is not
> a deceiver* it follows that in *cases like these* I am
> completely free from error. (AT 7:90, CSM 2:62; italics added)
> 



Central to the inference is the meditator's effort to check the
correctness of his belief, by means of his various faculties. The
*cases like these* to which Descartes refers look to be those
where conditions (i) and (ii) are both satisfied. Recall what
Descartes writes in conjunction with the proof of the external
material world: from "the very fact that God is not a
deceiver" there is a "consequent impossibility of there
being any falsity in my opinions which cannot be corrected by some
other faculty supplied by God" (AT 7:80, CSM 2:55f). Perhaps,
therefore, we can understand Descartes' theistic solution to the
Now Dreaming Doubt as building on the same *rule* he employs in
his proof for the external material world.



What about Hobbes's other objection - in effect, that one
could *dream* both (i) and (ii)? Descartes' response:
"A dreamer cannot really connect his dreams with the ideas of
past events, though he may dream that he does. For everyone admits
that a man may be deceived in his sleep" (AT 7:196, CSM 2:137).
Perhaps Descartes thinks the situation with dreaming parallels that of
waking life: those who are sufficiently tired, or otherwise
perceptually inattentive, "cannot really" perceive truths
clearly and distinctly, though it may *seem* to them that they
do. Whether in waking or dreaming, the Fourth Meditation theodicy has
God allowing us to make judgment errors, provided that they are
correctable. Descartes is committed to holding that when our
perception is confused, we can in principle come to discover the
confusion - even if not easily. When we lack clear and distinct
perception, we are at fault (not God) for any resulting judgments, in
part because we can discover that our perception is confused.
Descartes needs it that the same principle holds even while dreaming.
(And again, nearly the entirety of the *Meditations* unfolds
under the supposition that, for all we know, we may presently be
dreaming.) For the case at hand - i.e., the possibility of
mistakenly judging *that I'm awake*, while in a dream
- Descartes needs it that we could, in principle, discover that
we're mistaken. Apropos of condition (ii), therefore, is whether
God has provided us a faculty by which to discover that we're
dreaming, on occasions when we wrongly believe ourselves to be awake.
Evidently, Descartes thinks so, as he tells Gassendi:



> 
> When, for example, we are asleep and are aware that we are dreaming,
> we need imagination in order to dream, but to be aware that we are
> dreaming we need only the intellect. (Replies 5, AT 7:358f, CSM 2:248)
> 



Importantly, Descartes does not say we can *easily* correct the
mistake of *dreaming that we're awake*. To the contrary,
the Sixth Meditation treatment of the Now Dreaming Doubt closes with a
concession that his solution is perhaps more theoretical than
practical:



> 
> But since the pressure of things to be done does not always allow us
> to stop and make such a meticulous check, it must be admitted that in
> this human life we are often liable to make mistakes about particular
> things, and we must acknowledge the weakness of our nature. (AT 7:90,
> CSM 2:62)
> 



Thus the importance of Descartes' First Meditation remark that
"no danger or error will result" from the program of
methodical doubt, "because the task now in hand does not involve
action" (AT 7:22, CSM 2:15). Methodical doubt should not be
applied to practical matters. Prudence dictates that when making
practical decisions I should assume I'm awake, even if I
don't perfectly know that I'm awake. Judgment errors made
while *mistakenly assuming I'm awake* do not have
actual practical consequences, unlike those made while *mistakenly
assuming I'm dreaming*.



(For further discussion, see Newman 1999, Williams 1978, and
Wilson 1978.)


## 9. Self-Knowledge


### 9.1 That Mind is Better-Known than Body



Descartes holds that our judgments about our own minds are
epistemically better-off than our judgments about bodies. In our
natural, pre-reflective condition, however, we're apt to confuse
the sensory images of bodies with the external things themselves, a
confusion leading us to think our judgments about bodies are
epistemically impressive. The confusion is clearly expressed
(Descartes would say) in G. E. Moore's famous claim to knowledge
- "Here is a hand" - along with his more
general defense of common sense:



> 
> I begin, then, with my list of truisms, every one of which (in my own
> opinion) I *know*, with certainty, to be true. ... There
> exists at present a living human body, which is *my* body. This
> body was born at a certain time in the past, and has existed
> continuously ever since ... But the earth had existed also for
> many years before my body was born ... (1962, 32f)
> 



In contrast, Descartes writes:



> 
> [I]f I judge that the earth exists from the fact that I touch it or
> see it, this very fact undoubtedly gives even greater support for the
> judgement that my mind exists. For it may perhaps be the case that I
> judge that I am touching the earth even though the earth does not
> exist at all; but it cannot be that, when I make this judgement, my
> mind which is making the judgement does not exist. (*Prin*.
> 1:11, AT 8a:8f, CSM 1:196)
> 



Methodical doubt is intended to help us appreciate the folly of the
commonsensical position - helping us recognize that perception
of our own minds is "not simply prior to and more certain
... but also more evident" than perception of our own
bodies (*Prin*. 1:11, AT 8a:8, CSM 1:196). "Disagreement
on this point," writes Descartes, comes from "those who
have not done their philosophizing in an orderly way"; from
those who, while properly acknowledging the "certainty of their
own existence," mistakenly "take 'themselves'
to mean only their bodies" - failing to "realize
that they should have taken 'themselves' in this context
to mean their minds alone" (*Prin*. 1:12, AT 8a:9, CSM
1:196).



In epistemological contexts, Descartes purports to establish the
mind-better-known-than-body doctrine with methodical doubt. For
example, while reflecting on his epistemic position in regard both to
himself, and to the wax, the Second Meditation meditator says: 



> 
> Surely my awareness of my own self is not merely much truer and more
> certain than my awareness of the wax, but also much more distinct and
> evident. For if I judge that the wax exists from the fact that I see
> it, clearly this same fact entails much more evidently that I myself
> also exist. It is possible that what I see is not really the wax; it
> is possible that I do not even have eyes with which to see anything.
> But when I see, or think I see (I am not here distinguishing the two),
> it is simply not possible that I who am now thinking am not something.
> (AT 7:33, CSM 2:22)
> 



Further reasons might be helping to motivate Descartes' view.
On the kind of representational theory of perception that is widely 
attributed to him, our sense organs and nerves serve as literal mediating links in the causal chains generating sense perception:
they stand between (both spatially and causally) external things themselves, and the brain events occasioning our perceptual
awareness (cf. *Prin*. 4:196). In veridical sensation, the 
objects of immediate sensory awareness are not external bodies 
themselves, nor are we immediately aware of the states of our sense 
organs or nerves. Rather, the objects of immediate awareness are 
- whether in veridical sensation, or in dreams - the 
mind's own *ideas*. Descartes indeed holds that the
fact of physiological mediation helps explain delusional ideas,
because roughly the same kinds of physiological processes that
produce waking ideas are employed in producing delusional ideas:



> 
> [I]t is the soul which sees, and not the eye; and it does not see
> directly, but only by means of the brain. That is why madmen and those
> who are asleep often see, or think they see, various objects which are
> nevertheless not before their eyes: namely, certain vapours disturb
> their brain and arrange those of its parts normally engaged in vision
> exactly as they would be if these objects were present.
> (*Optics*, AT 6:141, CSM 1:172; cf. AT 7:85ff and AT 11:248f)
> 



Various passages of the *Meditations* lay important groundwork
for this theory of perception. For instance, one of the messages of
the wax passage is that sensory awareness does not reach to external
things themselves: 



> 
> We say that we see the wax itself, if it is there before us, not that
> we judge it to be there from its colour or shape; and this might lead
> me to conclude without more ado that knowledge of the wax comes from
> what the eye sees, and not from the scrutiny of the mind alone. But
> then if I look out of the window and see men crossing the square, as I
> just happen to have done, I normally say that I see the men
> themselves, just as I say that I see the wax. Yet do I see any more
> than hats and coats which could conceal automatons? I *judge*
> that they are men. (Med. 2, AT 7:32, CSM 2:21)
> 



Descartes thinks we're apt to be "tricked by ordinary
ways of talking" (*ibid*.). In ordinary contexts we 
don't say that it *seems* there are men outside the 
window; we say that we *see* them. Nor, in such contexts,
are our beliefs about those men apt to result from conscious, 
inferentially complex judgments, say, like this one: "Well,
I appear to be awake, and the window pane looks clean, and 
there's plenty of light outside, and so on, and I thus
conclude that I am seeing men outside the window." Even
so, our ordinary ways of speaking and thinking often mislead. 
Descartes' view is that the mind's immediate perception 
does not, strictly speaking, extend beyond itself, to external
bodies. This is an important basis of the mind-better-known-than-body 
doctrine. In the concluding paragraph of the Second Meditation, 
Descartes writes:



> 
> I see that without any effort I have now finally got back to
> where I wanted. I now know that even bodies are not strictly
> [*proprie*] perceived by the senses or the faculty of
> imagination but by the intellect alone, and that this perception
> derives not from their being touched or seen but from their being
> understood; and in view of this I know plainly that I can achieve an
> easier and more evident perception of my own mind than of anything
> else. (AT 7:34, CSM 2:22f)
> 



The understanding of ideas as the only immediate objects of
awareness arises in a number of texts. In the Sixth Meditation,
while discussing sense perception and our ideas of external things, 
Descartes writes that the mind's sensation extends strictly
and immediately only to the ideas: "the ideas were, strictly 
speaking, the only immediate objects of my sensory awareness
[*solas proprie et immediate sentiebam*]" (AT 7:75,
CSM 2:52). The Second Replies defines *thought* "to 
include everything that is within us in such a way that we are 
immediately aware of it"; it defines *idea* in
terms of the "immediate perception" that makes us 
"aware of the thought" (AT 7:160, CSM 2:113). And
in the Third Replies Descartes writes: "I make it quite
clear in several places ... that I am taking the word 
'idea' to refer to whatever is immediately perceived
by the mind" (AT 7:181, CSM 2:127).



Complicating an understanding of such passages is that Descartes
scholarship is divided on whether to attribute to him some version of
an indirect theory of perception, or instead some version of a direct
theory. According to indirect perception accounts, in normal sensation
the mind's perception of bodies is mediated by an awareness of
its *ideas of* those bodies. By contrast, direct perception
interpretations allow that in normal sensation the mind's ideas
play a mediating role, though this role doesn't have ideas
functioning as items of awareness; rather, the objects of direct
awareness are the external things, themselves. On both accounts, ideas
mediate our perception of external objects. On direct theory accounts,
the mediating role is only a process role. By analogy, various brain
processes mediate our perception of external objects, but in the
normal course of perception we are not *consciously aware* of
those processes; and likewise for the mind's *ideas*,
according to direct perception accounts. On one recent version of an
indirect perception interpretation, sensory ideas mediate our
perception of the external bodies they're of, in much the same
way that pictures (or other representational media) mediate our
perception of what they portray (Newman 2009). More generally,
Descartes seems to view all ideas as mental pictures, of a sort. As he
writes: "the term 'idea' is strictly
appropriate" only for thoughts that "are as it were the
images of things" (Med. 3, AT 7:37, CSM 2:25); he adds that
"the ideas in me are like {pictures, or} images" (Med. 3,
AT 7:42, CSM 2:29). 



Indirect perception interpretations have figured prominently in the
history of Descartes scholarship. A number of recent commentators,
however, have challenged this traditional view. For example,
Carriero defends a direct perception interpretation: "I don't read Descartes as holding that I am (immediately)
aware only of my sensory ideas and only subsequently (and perhaps 
indirectly) aware of bodies or their qualities" (2009, 25).
Thus on Carriero's reading, Descartes' broader argument 
rebutting our doubts about the external world is not to be understood 
as an effort to get on the other side (as it were) of our ideas:



> 
> The argument (as I understand it) is not intended to get us from a
> realm of inner mental objects ("sensory ideas") to some
> other realm of outer, physical objects ("bodies"); rather,
> it is to confirm our instinctive feeling that we have been receiving
> information ("directly") from outer objects, bodies, all
> along. (2009, 26)
> 



(For further discussion of Descartes' theory of ideas and
perception, see Carriero 2009, Chappell 1986, Cunning 2010,
Hoffman 1996 and 2009, Jolley 1990, Nadler 2006, Nelson 1997, 
Newman 2009, 2011, and Smith 2014.)


### 9.2 Whether We Perfectly Know Our Own Minds



We have seen that the proper use of our cognitive faculties requires
us to withhold assent except when our perception is clear and distinct
- indeed, that forming judgments in accord with the C&D Rule
provides the only guarantee of truth. Let's apply this standard
to introspective judgments. Suppose that the present contents of my 
mind include a confused array of ideas - say, a confused 
assemblage of auditory ideas, or color ideas, or perhaps I am
presently flooded with a confused assortment of ideas of emotion.
In such cases, the proper use of my faculties requires me to withhold 
judgment about the present state of my mind.



It is surprising, therefore, to learn that on the standard view in
Descartes scholarship, he holds a strong view of privileged access
guaranteeing the truth of *all* introspective judgments about
the present contents of our own minds. The usual result is an
infallibility thesis whereby judgments about our own mental states
cannot be mistaken if based on introspective awareness: if
I *seem* to be in mental state *x*, then I *am*
in *x*. (A variety of related doctrines are also sometimes
attributed to him, including the *indubitability* of the mental
- roughly, that introspective judgments are indubitable;
and *omniscience* with respect to the mental - roughly,
that one has knowledge of every true proposition about one's own
present contents of consciousness. There is some variation in the way
these doctrines are formulated in the literature.)



At least two lines of argument are widely cited in support of this
standard interpretation. One draws on the transparency doctrine. The
other draws on texts interpreted as providing support. Let's 
examine both.



The transparency doctrine has it that we are aware of everything
occurring in our minds - this, a result of Descartes' view
that *thinking* constitutes the *whole* essence of
mind:



> 
> As to the fact that there can be nothing in the mind, in so far as it
> is a thinking thing, of which it is not aware, this seems to me to be
> self-evident. For there is nothing that we can understand to be in the
> mind, regarded in this way, that is not a thought or dependent on a
> thought. ... and we cannot have any thought of which we are not
> aware at the very moment when it is in us. (Replies 4, AT 7:246, CSM
> 2:171f)
> 



Add to this that, unlike with external sensation, there is no
introspective appearance/reality gap, and there can seem to be no room
for introspective errors. Zeno Vendler explains:



> 
> If the mind, at any given time, is identical with a certain complex of
> thoughts ... then the very idea of a *medium* between the
> mind and its thoughts is impossible from the outset. Accordingly, it
> is an understatement to say that the mind *knows* its thoughts;
> the mind *is* these thoughts. (1972, 191)
> 



Kenny adds:



> 
> The occurrence of thoughts is not open to doubt or error. Thoughts
> cannot occur without our knowing that they occur, and we cannot think
> that a thought is occurring unless that thought actually is occurring.
> (1968, 72)
> 



In opposition to this standard interpretation, note that from the
fact that I have awareness of whatever is occurring in my mind, it
does not follow that I have *distinct* awareness. If
what's occurring in my mind is a confused muddle of ideas, then
I'll be aware of a confused muddle of ideas. But in that case,
forming a judgment about the present state of my mind is a recipe for
error - i.e., given the Fourth Meditation account of proper
judgment. The situation is arguably better in cases in which I
am experiencing fewer and simpler ideas; this is because such ideas
are generally easier to render clear and distinct. Even so, such
ideas must actually be rendered *as* clear and distinct.
Noteworthy is that Descartes writes, of "sensations, emotions
and appetites," that "we are frequently wrong in our 
judgements concerning them"; adding, that we can avoid such
errors "provided we take great care in our judgements
concerning them to include no more than what is strictly contained
in our perception - no more than that of which we have inner
awareness" (Prin 1:66, AT 8a:32, CSM 1:216).



Consider another case that seems at odds with the standard
interpretation. Were Descartes committed to introspective
infallibility, then he *should* say that we could never
be mistaken as to whether our occurring ideas are ideas of
*sensation*, or instead ideas of *imagination*
occurring in a dream. Yet as we've seen, he takes
dreaming-based scepticism utterly seriously.



What about the textual line of argument regularly cited in support
of the standard interpretation? Consider two *Meditations*
passages that can seem to entail the infallibility thesis:



> 
> 
> I certainly *seem* to see, to hear, and to be warmed. This
> cannot be false; what is called "having a sensory
> perception" is strictly just this, and in this restricted sense
> of the term it is simply thinking. (Med. 2, AT 7:29, CSM 2:19)
> 
> 
> 
> Now as far as ideas are concerned, provided they are considered solely
> in themselves and I do not refer them to anything else, they cannot
> strictly speaking be false; for whether it is a goat or a chimera that
> I am imagining, it is just as true that I imagine the former as the
> latter. As for the will and the emotions, here too one need not worry
> about falsity; for even if the things which I may desire are wicked or
> even non-existent, that does not make it any less true that I desire
> them. (Med. 3, AT 7:37, CSM 2:26)
> 
> 
> 



Prima facie, it is plausible to take such passages to entail that if
I *seem* to be having an idea of blue, or an idea of a noise,
or of warmth, etc., then I *am*. Indeed, one might take such
passages to convey that judgments to this effect "cannot be
false" *because* introspective judgments are infallible.
But note the continuation of the second passage: "Thus the only
remaining thoughts where I must be on my guard against making a
mistake are judgements." This suggests that these passages can
be read in a very different way. Accordingly, a *mere seeming*
"cannot be false" because it is not the kind of mental
state that *could* be false; on Descartes' view,
*falsity* arises not simply from the mind's awareness
of its ideas, but from judgments - i.e., from acts of will 
assenting to those items of awareness. Read in this way, these
passages anticipate the Fourth Meditation theory of judgment:



> 
> Now all that the intellect does is to enable me to perceive the ideas
> which are subjects for possible judgements; and when regarded strictly
> in this light, it turns out to contain no error in the proper sense of
> that term. (AT 7:56, CSM 2:39)
> 



Arguably, Descartes' mind-*better*-known-than-body
doctrine is intended as a *comparative* rather than a
*superlative* thesis. We have seen that, for Descartes, the
only superlative perceptual state is that of clarity and distinctness.
This suggests that the only guarantee of truth in our introspective 
judgments is, like all other judgments, that they be based on clear 
and distinct perception: if I clearly and distinctly perceive myself
to be in mental state *x*, then I *am* in *x*.



(For further discussion of related issues in Descartes, see Alanen 
2003, Broughton 2008, Curley 2006, Jolley 2013, Kenny 1968,
LoLordo 2005, McRae 1972, Newman 2023, Nolan & Whipple 2005,
Vendler 1972, and Wilson 1978.)