## 1. Guiding commitments


### 1.1 Universal intelligibility



One of Spinoza's most fundamental epistemological and
methodological commitments is a commitment to universal
intelligibility. In his most influential treatise, the
*Ethics*, Spinoza expresses this commitment in two ways: first,
as the axiom that there is nothing that cannot be
"conceived", either "through itself" or
through "another thing" (*Ethics* [=
**E**] 1ax2); second, as the claim that there is a
"reason *or* [i.e.] cause" for the "existence
or nonexistence" of every thing (E1p11atld1).



These formulations immediately raise several questions. What does it
mean for something to be conceived "through itself", i.e.,
in some sense be *self*-explanatory? Does the equivalence of
causes and reasons suggested by E1p11altd1 mean that only appeals to
*causes* can furnish reasons? Indeed, what counts as a
"reason" (cf. Lin 2018)? It's often assumed that in
Spinoza's view to give a "reason" for something
requires engaging in the sort of apriori deductions that fill large
swathes of the *Ethics*. The opening definition of the
treatise, according to which something is a "cause of
itself" if its existence is implied by its essence (E1def1),
suggests that at least some of the relevant "reasons" will
indeed be accessible apriori. But could sense experience also furnish
us with reasons? Is seeing my dog play with a stick enough of a
"reason" to "conceive" of her as existing, or
must I deduce her necessary existence from the infinitely long series
of prior causes (E1p28), a task Spinoza admits is impossible for
finite minds like ours (*Treatise on the Emendation of the
Intellect* [= **TIE**] SS100)?



Controversially but influentially, Michael Della Rocca 2008 has argued
that Spinoza's philosophy as a whole can be derived from his
commitment to intelligibility. (For criticisms see e.g. Laerke 2011,
Newlands 2018, Renz 2018.)


### 1.2 Attribute barrier



A second guiding but unintuitive commitment of Spinoza's
epistemology has come to be known as the "attribute
barrier". A Spinozistic "attribute" is a descendant
of the Cartesian "principal attribute" (AT 8a.25):
roughly, it is the most basic qualitative kind under which something
can fall. For example, to say that something is a mental thing or a
physical thing - or, in Spinoza's and Descartes's
terminology, "thinking" or "extended" -
is to understand it in terms of its particular
"attribute".



Most commentators take Spinoza to uphold a total explanatory
*closure* of mental and physical realms: pace Descartes, no
physical thing can enter into conceptual or explanatory relations with
anything mental, and vice versa. For example, regardless of how we
might experience things, no physical occurrence, such as shaking a
fist at someone, can be made intelligible by appealing to anything
mental, like a menacing intention. Analogously, no bodily injury can
make intelligible the feeling of pain.



This prohibition on any "explanatory flow" (Bennett 1984)
between mental and physical realms is the core meaning of
Spinoza's attribute barrier doctrine. Given Spinoza's
commitment to universal intelligibility (see 1.1), derivatively, the
impossibility of conceptual relations between minds and bodies implies
the impossibility of *causal* relations between them (E3p2s).
For if something is in principle unintelligible (as any purported
causal relation between minds and bodies would be), it is also
metaphysically impossible. This prohibition on causal interactions
between mental and physical things is the key secondary meaning of the
barrier doctrine.



Given that ordinarily we *do* appeal to intentions in
explaining our physical actions and to bodily states in explaining
sensations, what would lead Spinoza to such a prima facie implausible
doctrine? The reason ultimately has to do with how Spinoza understands
the nature of the most fundamental entity in his metaphysics,
"substance". Building on philosophical tradition that goes
back to Aristotle, Spinoza associates being a "substance"
with existential and explanatory self-sufficiency or independence
(E1def3). Each essential quality or "attribute" of
substance also must, Spinoza believes, manifest this independence
proper to substance: "Each attribute of a substance must be
conceived through itself" (E1p10). As a result, we cannot look
for an explanation of the fact that substance thinks, or of how it
thinks, anywhere else but in substance's thinking nature (for
example, we cannot appeal to the fact that it is also a material
thing, i.e., a substance with the attribute of
"extension"). In this sense substance as thinking is
"conceived through itself". The same reasoning will be
true of any other substantial attribute.



This gives us the basic application of the barrier doctrine: the fact
that God is a physical thing cannot explain God's nature as a
thinking thing; nor is explanation possible in the other direction.
But the barrier doctrine also extends to *creaturely*
intentions, sensations, and movements. Ontologically, all the things
familiar to us from ordinary experience - animals, plants,
inanimate objects - are for Spinoza merely modifications or
"modes" of the single substance, "ways
[*modis*]" that God is, just as (to borrow examples from
Lin 2018) a wrinkle in a rug is one way a rug can be, and a fist one
way a hand can be. Spinoza explicitly applies the barrier doctrine
also to modes, stating that no modification of the thinking substance
can require for its explanation the concept *extension*, and no
modification of the extended substance can require for its explanation
the concept *thought*:



> 
> each attribute is conceived through itself without any other (by
> 1p10). So the modes of each attribute involve the concept of their own
> attribute, but not of another one. (E2p6d)
> 



(On attributes, see e.g. Gueroult 1958, Deleuze 1968, Shein 2009, Lin
2019.)


### 1.3 The priority of an infinite thinker



As we just saw, Spinoza derives his prohibition of mental explanations
of physical actions from what he takes to be true of the relation
between the mental and the physical in the case of *God.* This
is an instance of a more general methodological and epistemological
principle Spinoza holds dear, that of the *explanatory
priority* of claims about substance (God) to claims about modes
(creatures) (E1p1, E1p15). To return to our toy analogy, we can only
understand what it is to be a wrinkle in a rug if we first understand
what it is to be a rug. For Spinoza, philosophizing in proper order
always requires us to start with God (E2p10s).



Given this explanatory priority of substance, to understand what it
means to *think* or to have a *mind* we also cannot
simply extrapolate from *our* own case (for example, from
introspection, or from observing the behavior of fellow humans).
Rather, to understand thought and mindedness we first have to
understand the nature of *divine* thought, i.e., what it means
to be an "infinite" - unlimited and self-sufficient
- thinker. This is the fundamental case of thinking for
Spinoza.



What does this infinite thought amount to? In one sense, it is simply
an endorsement of the traditional doctrine of divine omniscience. In
Spinoza's framework, this doctrine becomes the claim that, as a
thinking thing (i.e., a substance with the attribute of thought) God
necessarily *produces* an "infinite idea", that is,
an infinite modification of God's nature as a thinking thing
(E2p1, E2p3, E2p7c). This infinite idea is a complete and veridical
representation of everything that is, every bit of reality (E2p32).
(Spinoza also calls this infinite mode an "infinite
intellect" [E2p11c], seemingly without distinguishing the two
terms.)



It's worth keeping in mind that Spinoza is making here two
distinct claims: to say that God is a substance with the attribute of
thought (that is, a thing whose essential nature it is to think) is
ontologically and explanatorily *prior* to the claim that this
thinking substance also *produces* an actual representation or
idea of everything (which is a claim about the existence of a certain
kind of infinite *mode*). So although Spinoza faithfully
follows tradition in endorsing the claims that God thinks and is
omniscient, he also ends up with a quite nontraditional result: the
divine "infinite intellect" is not part of, or identical
with, divine *nature* *or essence*. In terms of its
ontological status, the divine intellect is on par with finite minds
insofar as these too are merely modes.



The belief that the metaphysically basic instance of thinking is the
thinking done by an infallible and omniscient thinker goes some way
toward explaining why Spinoza seems unconcerned about the threat of
skepticism, so salient for Descartes (see also 3.1). For Spinoza
thought in its fundamental instance is necessarily true; it
"agrees" (E1ax6) with how things really are. So
*global* skepticism is simply a metaphysical impossibility; all
that remains of the skeptical threat is to be on guard against local
instances of confusion and error that become possible in the
derivative case of finite thought. Moreover, all such confusion and
error need some further cause beyond the intrinsic nature of thought.
(Indeed, one might worry that Spinoza lets the pendulum swing too far
in the opposite direction: global skepticism might no longer be
possible, but it might now be hard to see how *error* could be
possible, if, in Spinoza's substance-monistic framework, all
ideas are ultimately God's own [see 3.2.2].)



(On Spinoza's understanding of thinking, see e.g. Melamed 2013,
Newlands 2018, Renz 2018; on his two proofs that God thinks, e.g.
Della Rocca 1996, Gueroult 1974; on skepticism, e.g. Carriero 2020,
Perler 2018, Primus 2017.)


### 1.4 Philosophy as a way of life



Last but not least, we should not forget that Spinoza's magnum
opus carries the title *Ethics.* For him knowledge is not
merely a *theoretical* achievement, as if we were solving
conceptual puzzles for their own sake. For Spinoza, what is at stake
in understanding anything, including thinking and knowledge, is a
whole slew of *practical* goods: freedom, virtue, blessedness.
Of the infinity of knowable things, Spinoza writes, he wants to write
only about "those that can lead us, by the hand, as it were, to
the knowledge of the human Mind and its highest blessedness"
(E2pref).


## 2. Philosophy of mind


### 2.1 Minds


#### 2.1.1 Minds as bundles



One reason why Spinoza might not care about distinguishing between
calling something God's "idea" and calling it
God's "intellect" (see 1.3) is that, like Hume, he
appears to endorse what we today would call the "bundle
theory" of mind. On this theory, there is nothing more to
"minds" and "intellects" than collections of
ideas of various complexity. (For example, the "idea that
constitutes the formal being of the human mind is...composed of a
great many ideas" [E2p15].) In particular, minds do not contain
any specialized "faculties", such as will or intellect
(E2p48). If notions of such faculties are to have any validity at all,
they must be understood as mere *abstractions* from particular
ideas and particular volitions (E2p48s; G/II/130).



For Spinoza, what *individuates* one bundle of ideas from
another seem to be their intentional objects, i.e., what they represent
(E2p13s; see 2.1.3-4). For example, the aforementioned highly
composite idea that is the "human mind" has a certain
"actually existing body" as its essential object (see
2.2).



(On Spinoza's bundle view of the mind, see e.g. Della Rocca
1996; Hubner 2019; Renz 2018. On abstraction, see 3.2.4; on the
relation between ideas and affirmations, see 2.4; on the human mind
specifically see 2.2.)


#### 2.1.2 Minds as parts



Spinoza's ground-floor commitment to substance monism (i.e., to
the metaphysical possibility of only one "substance", or
existentially and explanatorily independent thing) leaves him with the
problem of how to understand the ontological status of *finite*
thought. If only one substance exists, what are we to make of human
minds? These cannot be thinking *substances* as they are, say,
for Descartes or Leibniz. Short of condemning all finite thinking as
illusory, Spinoza seems to have only one option left: to identify
certain instances of *God's* own thoughts with finite
thinking. And this is exactly what Spinoza does: he proposes that we
regard all finite ideas, and all the finite "minds" these
ideas compose (see 2.1.1), as "parts" of the divine
"infinite intellect":



> 
> the human mind is a part [*pars*] of the infinite intellect of
> God. Therefore, when we say that the human mind perceives this or
> that, we are saying nothing but that God, not insofar as he is
> infinite, but insofar as he is explained through the nature of the
> human mind, or insofar as he constitutes the essence of the human
> mind, has this or that idea. (E2p11c)
> 



Finite minds are thus for Spinoza both *modes* of a thinking
*substance* and *parts* of an *infinite*
*mode* that is God's own "intellect".



The claim that finite minds are parts of the divine intellect may
answer the question of the ontological status of finite thought, but
it creates another puzzle: in what sense can a non-extended mind or
intellect be a "part", or have "parts",
moreover parts that are themselves "minds"?


#### 2.1.3 Panpsychism



As we just saw, Spinoza accommodates human minds within his
substance-monistic framework by carving up God's "infinite
intellect" into "parts". But he isn't
concerned solely with making room in his metaphysics for
*human* minds:



> 
> the things we have shown so far are completely general and do not
> pertain more to man than to other individuals, all of which, though in
> different degrees, are nevertheless animate [*animata*]. For of
> each thing there is necessarily an idea in God, of which God is the
> cause in the same way as he is of the [human mind] (E2p13s)
> 



This is Spinoza's thesis of panpsychism, or universal mindedness
(more precisely, universal at least for all "individuals"
or composite entities [E2def; G/II/100]). Panpsychism follows because
all it takes for there to be a finite "mind" in
Spinoza's view is that there be some "part" of the
omniscient divine intellect - some component idea of it -
that represents some discernible bit of being. So not only is there
nothing more to minds than ideas (2.1.1), there is nothing more to
creaturely minds than God's ideas.



Spinoza's panpsychism may certainly seem more *morally*
appealing than the vivisection-friendly Cartesian view that animals
are just more complex versions of tables and clocks. Yet one may also
wonder whether an account that can explain how *human*
mindedness is possible only by instituting a general principle -
namely, the divisibility of an omniscient infinite intellect into
component ideas - that ushers in also plant and mineral minds
has diluted the meaning of "mind" beyond recognition or
usefulness. Can an account that sees mindedness everywhere explain
phenomena that, to all appearances, are particular to *human*
rationality and self-consciousness? And is Spinoza not guilty here
simply of a profound confusion of categories: how can *my*
*mind* just be *God's idea* of something? Margaret
Wilson expressed the classic version of these worries, pessimistically
judging against Spinoza (1999: ch.9).



(On Spinozistic minds, see e.g. Alanen 2011, Koistinen 2018, Lin 2017,
Newlands 2012; on mind-relativity of representing, see e.g. Matheron
1969, Donagan 1988, Della Rocca 1996; on individuation of subjects,
Renz 2018.)


### 2.2 Human minds


#### 2.2.1 Ideas of bodies



Any plausible panpsychism will have to say something about how human
minds differ from all other minds that populate reality. Spinoza
accounts for the distinctiveness of the human mind in two ways. First,
as already noted, he underscores its *complexity* as a mental
operation or act of thinking. Using the Scholastic term "formal
being" to pick out this aspect of thinking, he writes,
"the idea that constitutes the formal being of the human mind
is...composed of a great many ideas" (E2p15). Second,
Spinoza proposes that human minds are also distinct by virtue of what
they essentially *represent*: the essential intentional object
of the human mind is an *actually existing body*:



> 
> 
> The object of the idea constituting the human mind is the body,
> *or* a certain mode of Extension which actually exists, and
> nothing else (E2p13)
> 
> 
> 
> the essence of the mind consists in this...that it affirms the
> actual existence of its body (E3GenDefAff [G/II/204]; cf. E2p11,
> E2p17s [G/II/105/32])
> 
> 
> 



In other words, a certain (itself complex) "part" of the
divine infinite intellect will count as a "human mind" iff
it essentially represents a certain physical existent. It is in this
intentional or representationalrelation (and not for example, *per
impossibile*, in some *causal* relation [see 1.2]) that the
mind-body "union" consists in Spinoza's view:
"We have shown that the Mind is united to the Body from the fact
that the Body is the object of the Mind" (E2p21d) (cf. Renz
2018).



A few clarifications are in order. First, on hearing of
Spinoza's view we might be inclined to protest that human minds
represent all sorts of things *other* than our own bodies:
ideas, abstractions, other bodies, etc. (Wilson 1999: ch. 9). But, to
be clear, Spinoza *isn't* proposing here, rather
implausibly, that we represent *nothing but* our own bodies.
His claim is rather about what constitutes the *essential*
intentional object of the human mind: other ideas composing my mind
may come and go, but to remain the same mind across time, and distinct
from other equally complex bundles of ideas, my mind must continue to
represent a particular physical entity. Moreover, Spinoza holds that
we are able to represent all the other things we represent only
because we first conceive of our own body (for details, see 3.2 and
4).



Second, that my mind has some actually existing body for its essential
intentional object also *doesn't* mean that I know this
body *adequately*. Far from it: "we have only completely
confused cognition of our body" (E2p13s; cf. E2p27). There are
several reasons Spinoza is led to this pessimistic verdict. For one,
as we saw, the human mind is essentially an idea of some existing body
and of "nothing else" (E2p13). In particular, the human is
*not* essentially an idea of the many *causes*
responsible for that body's composition and continued
functioning. But, on Spinoza's conception of knowledge,
understanding these causes would be necessary for a complete knowledge
of that body (E1ax4; cf. Donagan 1988: 129).



Here is another reason why the idea that makes our minds our minds is
"completely confused". According to Spinoza, the only way
I can cognize my own body as a particular thing existing in time (as
opposed to knowing its atemporal "essence", or knowing the
*general* properties of all bodies) is through its modes or
"affections" - that is, through the changes or
determinations that this body undergoes, mostly under the influence of
external causes (E2p19). "We feel that a certain body is
affected in many ways" (E2ax4): we stub our toes, hear a voice,
are warmed by the sun, etc. But what we grasp in such experiences is,
according to Spinoza, only a "confused" *amalgam*
of the nature of our own body *and* the nature of the external
causes affecting it (for details, see 3.2.2). But, however confused,
my first-personal "feeling" of what happens to my body
suffices for distinguishing my "mind" from my ideas of
other bodies: I don't "feel" in the same way what
happens to my sister's equally complex body (*her* mind
does), even if I can observe it (and even imitate it empathetically;
see E3p27).



(See 4 for continuation of this account; on sense experience and
error, see 3.1.2, 3.2.3.)


#### 2.2.2 Knowing your pancreas and other problems



Recognition that the idea of the body that essentially constitutes a
human mind is "completely confused" (E2p13s) goes some way
toward defusing Spinoza's otherwise baffling assertion that we
"perceive" "[*w*]*hatever* happens
in" that body (E2p12, emphasis added). Prima facie this
proposition ascribes, implausibly, a godlike omniscience to human
minds. But experience clearly tells against such a proposal: we
certainly aren't aware of *all* of the affections of our
bodies (i.e., of all that "happens in" them), down to the
cellular (and even quantum) level of each organ. It's much more
plausible to take Spinoza's claim to be that we have such
perceptions, but their utter confusedness or lack of clarity and
distinctness makes them indiscernible to us.



The initial implausible appearance of E2p12 dissolves even further
once we make note of Spinoza's *functional* understanding
of bodies: not everything that *we* might ordinarily consider a
"part" of a body falls under this concept for Spinoza (cf.
Donagan 1988:123):



> 
> parts composing the human Body pertain to the essence of the Body
> itself only insofar as they communicate their motions to one another
> in a certain fixed manner...and not insofar as they can be
> considered as Individuals, without relation to the human Body.
> (E2p24d)
> 



Accordingly, Spinoza will have a suitably narrower understanding of
the scope of "whatever happens in" the parts of our own
bodies: we will "perceive" only those affections of the
pancreas, say (to use Della Rocca's example [2018]), that bear
on the whole body's ability to function as an integrated
organism (cf. Garrett 2018: ch.14).



Even if we manage to make sense of the apparent ascription of
omniscience to human minds, at least two other problems for
Spinoza's account of the mind-body relation remain.



First, although tying the individuation of certain "parts"
of the infinite intellect to certain bits of reality that these parts
essentially represent may well solve the problem of individuating
finite minds in a substance-monistic framework (see 2.1.2), it also
seems to generate a new problem. This is that to explain the nature of
the human mind we must now appeal to the existence of
*bodies*:



> 
> to determine what is the difference between the human Mind and the
> others, and how it surpasses them, it is necessary for us, as we have
> said, to know the nature of its object, i.e., of the human body
> (E2p13s)
> 



The problem is that, as we know (1.2), Spinoza *prohibits*
cross-attribute explanations: no physical thing can explain anything
mental, and vice versa. Yet Spinoza's own account of the
essential constitution of human minds seems not just to *allow*
for such cross-attribute explanations, but to *require*
them.



Here is another interpretative problem that seems to plague
Spinoza's account of the human mind. How should we understand
the relation between 1) the intentional or representational relation
that human minds essentially bear to bodies, and 2) Spinoza's
claim that minds and bodies are "one and the same thing"
(E2p7s)? The doctrine of mind-body identity seems to follow directly
for Spinoza from *substance's* identity under different
attributes: since thinking substance and extended substance are in
fact just a single substance considered or described in two different
ways, so also all of substance's *modifications* will be
subject to that same sort of multiplicity of descriptions.
Accordingly, the human mind and the human body are numerically
"one and the same thing" (namely, a certain finite mode)
but this mode can be veridically described as a mind *or* as a
body. But when we pair this doctrine of mind-body identity with the
thesis of an essential representational relation between the mind and
the body, we are faced with the question, Why should a mind represent
what it is numerically identical with, or be identical with what it
represents? How do we make this twofold nature of the mind-body
relation intelligible?



(On mind-body identity, see e.g. Delahunty 1985; Della Rocca 1996;
Jarrett 1991; C. Marshall 2009; on its relation to mind-body
intentionality, Garrett 2018: ch.15; Hubner forthcoming; for
solutions to the barrier violation, e.g. Della Rocca 1996, Hubner
forthcoming, 2019.)


### 2.3 Consciousness and ideas of ideas



Given the importance of the concept of consciousness to contemporary
philosophy of mind, it is perhaps unsurprising that Spinoza's
readers have tried to extract a full-blown theory of consciousness
also from the rare appearances of terms such as *conscius* and
*conscientia* in his writings. Such efforts are also
unsurprising given Spinoza's historical placement between
Descartes (often taken to define thought in terms of consciousness)
and Leibniz (who distinguishes thinking as a perfectly general
property from consciousness as a property of higher minds alone) (cf.
LeBuffe 2010). Interpreters return again and again to certain
questions: did Spinoza even *have* a theory of consciousness in
a recognizable sense? If he did, was it an internally consistent and
adequately defended theory? Was it meant to distinguish conscious and
unconscious ideas (and so also conscious and unconscious minds [see
2.1.1])? Did Spinoza posit universal (but perhaps scalar or graded)
consciousness, just as he posited universal (but scalar or graded)
mindedness (see 2.1.3)?



The existing array of interpretations ranges widely, from
Curley's 1969 conclusion that for Spinoza
"consciousness" picks out *higher order* ideas
(that is, ideas of ideas); through proposals that the term is intended
to track the *complexity* (Nadler 2008) or the *power*
(D. Garrett 2018: ch.14, E. Marshall 2013) of ideas; to the claim that
Spinoza uses *conscius* and *conscientia* in several
different senses (LeBuffe 2010b).



The ideas-of-ideas reading of consciousness gets going because of
passages like E4p8d, where Spinoza characterizes
"cognition" of good and evil as
"consciousness" of certain emotions (given that
Spinozistic emotions or "affects" are already themselves
constituted in part by "ideas" [E3def3]) and E3p9s, where
Spinoza characterizes "desire" as "appetite together
with consciousness of appetite" (given that
"appetite" is already "related to the mind"
[E3p9s]). In both cases the implication seems to be that consciousness
is or involves higher order ideas.



Of course, this interpretation of consciousness is of no use to
someone looking to Spinoza for a theory of *selective*
consciousness, on which consciousness distinguishes some mental states
from others. This is because in Spinoza's framework there is no
idea of which there is no higher order idea. This follows, first, from
divine omniscience (an all-knowing God has ideas of all things,
including all ideas) and, second, from Spinoza's understanding
of ideas of ideas as *ways of* *regarding* the
first-order ideas, not numerically distinct from them. More precisely,
for Spinoza, an idea of idea A is just A considered only as an
*act* of thinking (leaving aside its representational content)
- or, to use his Scholastic terminology, it is the original idea
considered in its "formal reality" alone: it is "the
form of the idea...considered as a mode of thinking without
relation to the object" (E2p21s).



Interpretations on which consciousness is a scalar property tracking
complexity or power fare much better in accounting for texts in which
Spinoza depicts consciousness as a matter of selective causal and
cognitive achievement, as in the following:



> 
> He who, like an infant or child, has a body capable of very few things
> and very heavily dependent on external causes, has a mind which
> considered solely in itself is conscious of almost nothing of itself,
> or of God, or of things. On the other hand, he who has a body capable
> of a great many things, has a mind which considered only in itself is
> very much conscious of itself, and of God, and of things (E5p39s)
> 



(On consciousness see also Miller 2007.)


### 2.4 Willing or affirming



Spinoza's account of willing is developed in opposition to
Descartes's account, on several fronts. First, and perhaps most
famously, Spinoza denies that human beings have a *free*
(undetermined) will (E1app; G/II/78). The freedom that Descartes finds
undeniable in introspection is for Spinoza only a manifestation of the
depths of our ignorance about how we actually have been determined to
act. Second, Descartes had proposed that we distinguish intellect as a
faculty for forming representations, from will as a faculty for
judging the truth value of these representations. Spinoza rejects both
the idea that there *are* any faculties over and above
particular ideas and volitions (cf. 2.1.1), and the separation of the
representational and volitional elements. Instead he proposes that we
see the volitional element as *intrinsic* to representation,
such that we "affirm insofar as [we] perceiv[e]" (E2p49s
[III.B(ii)]; G/II/134). In consequence Spinozistic ideas are
*belief-like:* they "affirm" - posit the
existence of - the things they represent. On this picture, in
thinking of my dog, for example, I thereby affirm her existence.



One obvious objection a Cartesian might make to this account is that
it seems incapable of explaining the familiar experience of merely
entertaining (imagining, hypothesizing, exploring, etc.) some idea
without committing ourselves to its truth or falsity. As Spinoza puts
the objection in the mouth of an imaginary opponent,



> 
> someone who feigns a winged horse does not on that account grant that
> there is a winged horse, i.e., he is not on that account
> deceived...Therefore, experience seems to teach...that the
> will, or faculty of assenting, is free, and different from the faculty
> of understanding. (E2p49s [III.A.(ii)])
> 



To fend off this objection Spinoza must find a way of explaining the
possibility of representing something (such as a winged horse) without
committing to its existence, while drawing solely on the resources of
particular, intrinsically affirmative ideas. His proposal focuses on
*countervailing* ideas: ideas that affirm or posit something
that negates or "excludes [*tollere*]" the
existence of an object represented by other ideas. For example, a
child "imagining a winged horse, and not perceiving anything
else...that excludes the existence of the horse....will
necessarily regard the horse as present" (E2p49s [III.B.(ii)];
G/II/134). But, with some schooling, the child's original idea
of a winged horse can be offset by another idea (say, by the rational
representation of equine bones as, in general, too heavy to be lifted
by feathers). Spinoza's proposal explains not only how the
ordinary experience of mere entertainment of ideas is possible, but,
more significantly, it arguably offers a genealogy of
*negation* as a basic mental operation derived from affirmation
(cf. Donagan 1988:46).



The obvious question Spinoza's account raises is why, in such
cases of mental conflict, in which certain ideas "exclude"
one another, should one of these ideas prevail? As Diane Steinberg
notes, Spinoza cannot have in mind purely *logical*
inconsistency or contradiction between ideas, since this doesn't
yet give us a reason to nonarbitrarily prefer one idea over another
(2003). The psychology of "exclusion" must involve not
merely such logical incompatibility of contents, but something that
would asymmetrically tip the scales in favor of one idea. Commentators
have proposed that greater causal *power* as the best candidate
for this role: the winning idea is the idea with more power to
continue existing and to produce further ideas (in short, greater
power to "strive" [E3p7]), or greater power to determine
the mind's activity or causal power as a whole (e.g. Della Rocca
2003; J. Steinberg 2018b).



(On affirmation, will and excluding ideas see also 3.2.2. On
"fictions", see e.g. D. Garrett 2018: ch. 5, J. Steinberg
2018b; on striving, see e.g. Carriero 2011, Kisner 2011, LeBuffe 2010,
Viljanen 2011, Youpa 2020 and entry on
 Spinoza's psychological theory.)


## 3. Epistemology


### 3.1 Truth and adequacy



Spinoza is often taken to endorse the correspondence theory of truth,
that is, roughly, the view that truth consists in some sort of
conformity of thought to reality. Spinoza himself puts the point in
terms of "agreement": "A true idea must agree with
[*convenire*] its object" (E1ax6).



However, this relational property of "agreement" is not
the only way Spinoza characterizes truth. True Spinozistic ideas also
have an *intrinsic* and, arguably, introspectable (cf. Garrett
2018: ch.5) property which distinguishes them as true without
requiring us to look beyond the ideas themselves. An
"adequate" idea is one with this intrinsic property:



> 
> By adequate idea I understand an idea which, insofar as it is
> considered in itself, without relation to an object, has all the
> properties, or intrinsic denominations of a true idea. *Exp*.:
> say intrinsic to exclude what is extrinsic, viz. the agreement of the
> idea with its object. (E2def4)
> 



Consequently, truth can be "its own standard", such that
"he who has a true idea at the same time knows that he has a
true idea, and cannot doubt the truth of the thing" (E2p43, cf.
TIE SS36).



The view is surely puzzling: How is it that just by considering an
idea on its own, we can be certain that it in fact conforms to what it
represents? What might these intrinsic signs of truth be?



One plausible answer is that Spinoza has in mind here something like
clarity and distinctness (cf. e.g. E2p38c), and so is in broad
agreement with Descartes's "rule" that true ideas
can appear to us as clear and distinct. Don Garrett has suggested
that, in addition to clarity and distinctness, we should understand
adequacy as the "logical consistency of the represented
object" (2018: ch.6). On this reading, true ideas are
self-evidently true insofar as we can clearly and distinctly perceive
the logical consistency of what they represent. This proposal has the
virtue of tying together Spinoza's two characterizations of
truth - the extrinsic and the intrinsic one - into one
neat package: given Spinoza's commitment to necessitarianism
(E1p33, E1p35), any logically consistent idea will represent not just
a possible object but a necessary and actual one; hence we can know
from the logical consistency of an idea alone that it in fact
corresponds to its object.



The above definition of adequate idea in terms of a true idea's
intrinsic or nonrelational properties is, however, not the only way
Spinoza characterizes mental "adequacy". He also gives
what we could call a *mind-relative* account of adequacy. It is
made possible by his belief that finite minds are "parts"
of the omniscient "infinite intellect" (see 2.1.2). As he
explains, "there are no inadequate or confused ideas except
insofar as they are related to the singular mind of someone"
(E2p36d):



> 
> when we say that God has this or that idea, not only insofar as he
> constitutes the nature of the human Mind, but insofar as he also has
> the idea of another thing together with the human Mind, then we say
> that the human Mind perceives the thing only partially, or
> inadequately (E2p11c)
> 



In other words, if ideas constituting a given finite mind suffice for
representing *x* *in the same way* that a perfect
intellect would represent *x*, the mind in question represents
*x* "adequately". Eugene Marshall has usefully
expressed this point in terms of part-whole "containment":
ideas are adequate iff they are entirely a part of, i.e., contained in,
the relevant finite mind (2013:26).



Here is an example of how this might work. Consider once again
Spinoza's claim that the idea of the body that essentially
constitutes a human mind is "completely confused" (see
2.2.1). We can put this point in terms of *inadequacy*: a human
mind knows its body as a particular in duration only by perceiving how
it is "affected" or changed. This idea of the body is
"inadequate" in Spinoza's technical sense because
God's conception of that body includes many components that are
not also part of the human mind's conception of it: God
conceives of all the many bodies that go into composing, preserving,
and "regenerating" the affected human body, as well as of
all the affecting external bodies, and of the infinite series of
causes on which these bodies in turn depend (E2p19d).



Confronted with Spinoza's account of mental adequacy, we might
wonder how his two characterizations of this concept are supposed to
hang together: why should an idea entirely contained in a mind also
have certain intrinsic markings of truth, such as clarity and
distinctness? One way to reconcile these two claims is to infer that
for Spinoza only ideas whose "premises", so to speak, are
wholly contained in a given mind can also appear as manifestly or
self-evidently true. (One might also wonder if finite minds like ours
can ever manage to think anything truly "adequately", if
this requires that *all* of the "premises" of a
given idea be contained in our minds [cf. Della Rocca 1996]. We come
back to this question in 3.2.1.)



Finally, some commentators have concluded, further, that an
"adequate" idea must be contained in a mind insofar as it
must also have been "adequately caused" - i.e.,
self-sufficiently or autonomously caused - by the mind in
question, and as such counts as a true "action" of that
mind, in Spinoza's technical sense of these terms
(E3def1-2). If that's right, then adequate ideas must all
be *innate* (LeBuffe 2010, E. Marshall 2013, J. Steinberg
2018a: ch.8). For having a cause external to the mind - for
example, arising from experience - would be incompatible by
definition with having been "adequately caused". On such
readings, what we might experience as an *acquisition* of an
adequate idea (say, in a philosophy class) is in fact only a matter of
becoming *more conscious* of it (J. Steinberg 2018a: ch.8; see
2.3).



(See also Kisner 2011.)


### 3.2 Knowledge (*cognitio*)



The common English translation of Spinoza's *cognitio* as
"knowledge" does not do justice to his understanding of the term,
which includes not just true and adequate ideas, but also inadequate
and false ones.


#### 3.2.1 Cognition and causation



Perhaps the most important epistemological principle standardly
ascribed to Spinoza is that to conceive of or cognize *x*, one
must conceive of or cognize its *causes*. The text cited most
frequently in support of this causal interpretation of Spinozistic
cognition is E1ax4: "Cognition of an effect depends on, and
involves, cognition of its cause" (transl. altered). The
interpretation finds further support in what has come to be known as
Spinoza's "parallelism doctrine", the proposition
stating that "The order and connection of ideas is the same as
the order and connection of things" (E2p7). Spinoza's
appeal to E1ax4 in the demonstration of this proposition makes clear
that the "order and connection of things" he has in mind
in E2p7 is a *causal* order and connection (cf.
E2p9d)*.* The idea that at least for the omniscient
"infinite intellect" the connections between ideas
perfectly mirror the causal connections between things in nature
further supports the thought that for Spinoza cognizing something
requires tracking its causes.



Despite the fact that commentators often appeal to E1ax4, the meaning
of this important axiom is far from clear. There are two main
interpretive problems (leaving aside the question of what sorts of
causes, out of the rich panoply envisioned by the Aristotelians,
Spinoza might allow in his metaphysics). The first problem concerns
the *kind of cognition* at stake in E1ax4. Some readers (e.g.
Bennett 1984; Gueroult 1969) have proposed that the axiom governs
*adequate* cognition alone. So understood, the axiom expresses
a version of the traditional view that truly "scientific"
knowledge requires a knowledge of causes - the knowledge
*why* something happened, not merely *that* it happened.
But, as Margaret Wilson points out (1999: ch.10), this restricted
reading of the scope of the axiom can't be correct, since in
Spinoza's view even *inadequate* ideas formed in sense
experience "involve" their causes. (For example, the
inadequate knowledge I have of any bodily change
"involves" the inadequate knowledge of its external cause
[E2ax1', E2p25, E2p28].)



A second interpretive problem concerns the meaning of the two terms
- "dependence" and "involvement" -
used by Spinoza to characterize the relation between causes and
cognitions in E1ax4. "Involvement" is most often glossed
as "implication". But Wilson has argued that in key
passages (e.g. E2p45) *involvere* stands more specifically for
the relation of implication between an *attribute* concept
(e.g. *extension, thought*) and cognition of a mode (1999:
ch.10). On this reading of "involvement", Spinoza's
claim in E1ax4 that cognition of effects "involves" a
cognition of causes amounts to the relatively intuitive claim that
conceiving of extension or thought is necessary for conceiving of any
particular mind or body. So understood, the axiom doesn't direct
us to discover the causes of things so that we may have truly
scientific knowledge of them, but instead merely describes what is
entailed by even the most minimal and inadequate conception of
anything whatsoever.



In addition to E1ax4 and E2p7, the claim that for Spinoza all
cognition is cognition of causes also fits with his definition of
"adequate cause" as one "whose effect can be clearly
and distinctly perceived through it" (E3def1), which suggests
that causes are at least *sufficient* for adequately conceiving
of a thing. Likewise, in E1p11altd1, Spinoza appears to
*identify* the "causes" of a thing's
existence or nonexistence with "reasons [*ratio*]"
for that existence or nonexistence by means of the conjunction
*sive*.



Nonetheless, the claim that for Spinoza to conceive of *x*, one
must conceive of its *causes*, faces at least two problems.
First, it's not clear how to reconcile this position with
Spinoza's account of the human mind. As we saw (2.2), cognition
of the essence of human minds requires reference to actually existing
bodies; yet, given Spinoza's commitment to the attribute barrier
(1.2), bodies cannot stand in a causal relation to anything mental. So
either Spinoza's account of the human mind is invalid by his own
lights or (more likely) Spinoza allows for cognitions that do
*not* depend on a thing's causes. Second, since each
finite thing depends on an "infinite" series of prior
finite causes (E1p28), if cognition of a thing (or at least
*adequate* cognition of it) requires a grasp of *all*
its causes, this would put an implausible, "stratospherically
high" (Bennett 1984) requirement on cognition. Indeed it would
put such cognition outside the reach of minds like ours, since, as
Spinoza admits, we simply cannot know the entire infinite series of
finite things responsible for any given state of affairs in nature
(TIE SS100). Here Wilson's insight about how Spinoza uses
"involvement" is helpful: we *can* have adequate
causal cognition of particular things, as long as we look to God (the
first and universal cause of all things) and not to the infinite
series of prior *finite* things as the relevant cause, and as
long as we attempt to explain the *essence* of the particular,
not its durational states. Spinoza's doctrine of "common
notions" (see 3.2.3) guarantees that we have adequate ideas of
God under the attributes of extension and thought. And to know God as
the cause of the essence of a particular thing is just to have what
Spinoza calls "intuitive cognition" (see 3.2.5.)



(On causal cognition, see e.g. Koistinen 1996, Morrison 2013, 2015; on
reconciling it with mind-body account, Della Rocca 1996, Hubner
2020; on possibility of adequate cognition, e.g. Marshall 2013.)


#### 3.2.2 Kinds of cognition I: Imagination and falsity



Spinoza divides cognition into three kinds*:* imagination;
reason [*ratio*]; and intuition [*scientia intuitiva*].
This section focuses on the first of these.



First, a terminological warning: what Spinoza calls
"imagination" shouldn't be confused with what
*we* are likely to mean by that term today. By
*imaginatio* Spinoza understands sense experience (including
cognition from signs and testimony) and derivative mental processes
(including memory and the sort of manipulation of mental imagery we
indeed might call "imagination"). Spinozistic
*imaginatio* is distinct in virtue of both its content and its
causes. First, it is cognition of *external* *bodies* as
*present;* secondly, it is cognition acquired through ideas of
*affections*, i.e., changes, of our *own* body, caused by
other bodies:



> 
> affections of the human body whose ideas present external bodies as
> present to us, we shall call images of things, even if they do not
> reproduce the [NS: external] figures of things. And when the mind
> regards bodies in this way, we shall say that it imagines (E2p17s;
> G/II/106)
> 



(NB: "image" is another potential terminological trap for
today's readers: it's Spinoza's label for something
*physical*, a modification of the body. In contrast,
"imagination" names something mental: the act or operation
of representing, or forming ideas of, these physical
"images".)



One of the most important claims Spinoza makes about imaginative
cognition is that it comprises "all those ideas which are
inadequate and confused and so...is the only cause of
falsity" (E2p41d). That is, only ideas derived from sense
experience alone can *give rise* to false beliefs. The list of
objects of which, Spinoza thinks, we have only such inadequate and
confused cognition is staggering: it includes our own bodies; external
bodies; the affections, parts, and durations of both; finally, even
our minds (E2p19-31) (cf. 2.2.1). As Spinoza concludes
pessimistically, "all the notions by which ordinary people are
accustomed to explain nature are only modes of imagining, and do not
indicate the nature of anything" (E1app; G/II/83).



What sort of "confusion" does Spinoza have in mind in
E2p41d? Recall that imaginative cognition consists in ideas of
affections of, or changes in, our own bodies that *also*
present us, indirectly, with the *external* *causes* of
these changes. (As Spinoza puts it, all our ideas of our own,
externally-caused bodily affections "involve" the nature
of the external cause [E2p16].) So the "confusion"
inherent to imaginative cognition seems to do, first, with the fact
that imaginative ideas have a content that is an *amalgam* of
two distinct things: the current condition of some part of my body
*and* the properties of the external cause (E2p16, E2p25; cf.
Della Rocca 1996). For example, when I'm warmed by the sun, the
nature of that bodily change depends on the nature of the sun
*together with* the nature and current state of my own body. My
perception of the bodily affection - of the increased warmth
- tells me *something* about my own body and
*something* about the sun; I have some insight into the
*relative* properties of both things. But it doesn't tell
me about the intrinsic or fundamental nature either of my own body or
the sun. It also doesn't allow me to clearly separate out the
relative contributions of the external cause and of my own body.
(Indeed, Spinoza goes so far as to propose that that such ideas
"indicate the condition of our own body *more*
*than* the nature of the external bodies" [E2p16c2;
emphasis added].)



What about Spinoza's characterization of imaginative ideas as
"inadequate" (E2p41d)? Recall that "adequate"
ideas are *manifestly true* ideas *fully explained by the
mind* they help constitute (3.1). So, first, a *lack* of
adequacy is a lack of an intrinsic marker of truth, and hence of
*certainty* that we are dealing with true ideas. Hence when
dealing with imaginative ideas we're not yet able to
"distinguish" with certainty "between the true and
the false" (E2p402). Of course, we may stumble on the right
result (as when we correctly apply a memorized mathematical rule
accepted on authority [cf. E2p40s2]). But we cannot yet be sure that
our ideas manage to "agree" with, or correspond to,
reality.



Second, as inadequate, imaginative ideas won't *fully*
explain what they purport to be about. Arguably, the mind thinking
them won't possess all of the "premises" that
necessarily conclude in the idea in question. Instead, that idea will
have been produced by, and so will "involve", the natures
of the external causes that brought about the relevant affection of
the body. Instead of being orderly connected to all their premises in
the mind (according to what Spinoza calls the "order of the
intellect"), imaginative ideas will be connected to one another
according to the "common order of Nature" (E2p29s), that
is in a way that reflects the order of our happenstance encounters
with other bodies, and the idiosyncratic psychological associations
such encounters generate:



> 
> For example, a soldier, having seen traces of a horse in the sand,
> will immediately pass from the thought of a horse to the thought of a
> horseman, and from that to the thought of war, etc. But a Farmer will
> pass from the thought of a horse to the thought of a plow, and then to
> that of a field, etc. And so each one, according as he has been
> accustomed to join and connect the images of things in this or that
> way, will pass from one thought to another. (E2p18s)
> 



It is fairly easy to see how ideas whose premises are only partially
grasped, and which are haphazardly connected together, could become a
"cause of falsity" - that is, could easily generate
erroneous inferences and associations, as long as we have not yet
grasped ideas that would be needed to offset or "exclude"
(see 2.4) such erroneous inferences and associations:



> 
> the mind does not err from the fact that it imagines, but only insofar
> as it is considered to lack an idea which excludes the existence of
> those things which it imagines to be present to it (E2p17s)
> 



To take an example important for the history of philosophy, our belief
in free will, on Spinoza's analysis, is precisely a false belief
that follows from sense experience not offset by countervailing ideas:
it arises because "we are conscious of [our] actions and
ignorant of [their] causes" (E2p35s). Any perception of my own
action will be "inadequate" (i.e., merely partial or
"mutilated" by comparison to God's infallible idea
of that same action) if the ideas of all the necessitating causes of
that action are not also part of my mind. Such a
"mutilated" and "inadequate" idea of my own
action can generate a false belief in free will as long as I lack
potentially offsetting ideas - say, of the *general*
necessity of all actions in nature (e.g. E1p33), together with an
understanding of *myself* as subject to the very same laws as
any other natural thing (E3pref; G/II/138).



This picture of falsehood as the result of the confusion and
mutilation of ideas generated by sense experience, combined with the
absence of countervailing ideas, is behind Spinoza's claim that
"falsity" is "nothing positive", only a
relative "privation of knowledge" (E2p35) about the matter
at hand. (Falsity so understood must also be distinguished from an
"absolute" "ignorance" of something
[E2p35d].)



The lack of ideas that could exclude or offset false conclusions
carries another epistemic danger, and contributes to the loss of our
"power" to think in yet another way: any ideas we have
failed to exclude lie in the mind ready to be combined with any
*adequate* ideas we've managed to secure, thereby
undermining the epistemic good that the latter bring with them. For
example, if we have not yet excluded the ideas of *divine*
*goodness* or *divine* *purposiveness* from our
minds (see E1app), we can easily "join" such inadequate
ideas to the concept *God*.


#### 3.2.3 Kinds of cognition II: Intellect, common notions and reason



Spinoza contrasts confused and falsehood-inviting imagination with
"intellect", which he subdivides further into
"reason" and "intuition". Given
Spinoza's bundle-theoretic approach to minds (2.1.1), talk of
"intellect" is not intended to conjure up here some sort
of mental "faculty" over and above particular ideas.
"Intellect" is instead Spinoza's name for a certain
type of cognition, namely cognition that is "necessarily
true" (E2p41). That is, intellectual ideas necessarily
"agree" with, or correspond to, represented objects
(E1ax6; see 3.1). This "agreement" with how things really
are in the world allows intellectual ideas to both be "the same
in all men" (E2p18s), and to reflect the actual causal order of
things in nature. Hence Spinoza can also describe intellect as
cognition of things "through their first causes" (E2p18s,
cf. E2p7), that is, ultimately through the all-necessitating divine
essence that determines the causal order of things (E1p15, E1p16).
Intellectual ideas are also "adequate" (E2p41d), that is,
manifestly true and fully explained by the mind they help constitute
(3.1). Because intellectual ideas of truth and falsity in particular
are manifestly true, intellectual cognition enables us to
"distinguish the true from the false" with certainty
(E2p42).



So how do we get our hands on this cornucopia of epistemic goods?
Spinoza warns that "ideas which are clear and distinct in
us" (i.e., "adequate", or manifestly true, ideas)
"*cannot* follow from mutilated and confused ideas"
(E5p28d; emphasis added). This would seem to *preclude* any
possibility of progressing from imagination to intellect. Fortunately
Spinoza leaves an escape hatch in the form of "common
notions", which he calls, appropriately, the
"foundations" of reason, i.e., of the first of two kinds of
intellectual cognition (E2p40s1). We may not be able to generate clear
and distinct ideas from *confused* ideas, but not all is yet
lost, because according to Spinoza even brute sense experience
furnishes us with *some* necessarily true and adequate ideas
(or, on innatist readings [see 3.1], triggers or activates such
ideas).



More precisely, in Spinoza's view, in every encounter with
another thing, not matter how confused my ideas of both my own body
and the external body (3.2.2), I also form *necessarily
adequate* ideas of any properties that are both 1)
"common" to the interacting bodies and 2) "equally
in the part and in the whole" (E2p38). That is, I form
necessarily adequate ideas of any properties wholly and without
distinction present in each particular thing. For example, the
property of being *extended* is one such property: extension is
extension is extension, whether it belongs to me or to a mosquito
biting me; I am neither more nor less of a physical thing than a
mosquito is. Likewise, every body possesses the property of having a
capacity for "motion and rest" ("all bodies
agree...in that they can move now more slowly, now more quickly,
and that now they move, now they are at rest" [E2Ld]). For
Spinoza, all such properties that are both universally instantiated
("common" to all things) and non scalar ("equally in
the part and in the whole") are necessarily grasped correctly by
*any* mind. And all ideas of such properties - all
"common notions" - are necessarily adequate.



What is Spinoza's argument for this rather implausible claim,
that we simply cannot get certain properties (such as extension,
thought, motion and rest) *wrong*? As we have seen, a lot
hinges on this doctrine: nothing less than the very possibility of
intellectual emendation, of transcending the confusion and inadequacy
of mere imagination. The answer has to do with how Spinoza thinks
about what is responsible for the *absence* of adequacy. As we
saw above (3.2.2), in his view, any ideas of external bodies that I
form through mere sense experience will in fact be ideas of how those
bodies affect me. (For example, my empirical idea of *the sun*
in fact only represents one way the sun can affect my body in its
current state.) But common properties like extension are
"equally in the part and in the whole": wholly and without
distinction in each thing. So for the adequacy of my idea of the sun
*as extended* it does not matter if I'm representing
extension as it is in the sun, or as it is in my body, or as it is in
the "confused" amalgam of the two. Extension is extension
is extension. Because common notions are insulated against error in
this way, and because no idea inferable from an adequate idea can
itself be inadequate (E2p40), these notions can indeed form a
"foundation" of reasoning, and so be our entry point into
the realm of the intellect.



What is sometimes overlooked in discussions of common notions is that
Spinoza allows for *two kinds* of common notions: what we could
call 1) *universal* common notions, notions of truly
universally instantiated non-scalar properties, such as extension; and
2) *relative* common notions, ideas of properties "common
to, and peculiar to [*proprium*], the human body and certain
external bodies by which the human Body is usually affected
[*affici solet*], and is equally in the part and in the whole
of each of them" (E2p39). It's not obvious what to make of
this characterization of the second type of common notion. What counts
as being "peculiar" to what "usually" affects
us? For example, are the general ideas Spinoza relies on in his
account of the human mind and human emotions ("affects")
common notions in this more circumscribed sense? We could pose the
same question of *universal* common notions: what should we
include in that list, beyond the fairly uncontroversial examples of
*extension*, *thought*, *motion-and-rest?*



One interesting upshot of Spinoza allowing for this second, relative
type of common notion is that our ability to transcend mere sense
experience into the realm of reason is not simply a function of the
invariable ontological make-up of the world, of there being only so
many truly universal on/off properties. We can also *do*
something to increase the number of common notions that it is possible
for beings like us to have given our "usual" environments.
The more we can make it the case that we have something in common with
things around us - and in part this means, the more diverse
*we* ourselves are (cf. Sharp 2011: 98-9) - the
broader the epistemic "foundation" on which we can rely in
reasoning.



Finally, once again, the fact that no common notion *on its
own* can be a cause of falsity doesn't mean that we cannot
put common notions, of either kind, to bad use: we can still
"join" adequate ideas to ideas of more dubious value,
producing more complex *inadequate* representations (cf.
3.2.2). Hence even if we necessarily adequately conceive of God *as
a thinking thing*, we still are in danger of joining this adequate
idea to that of a benign or vengeful ruler as the referent of the name
*God*.



(On reason, see e.g. Kisner 2011; LeBuffe 2017, Malinowski-Charles
2010; on common notions, Donagan 1988; Primus 2017.)


#### 3.2.4 Generality and abstraction



Spinoza's doctrine of common notions is inseparable from a
larger interpretative puzzle. This puzzle concerns Spinoza's
stance on the validity of *general* concepts more broadly
- in particular, of concepts of kinds, such as *horse,
animal*, or *being*.



Certain things are fairly clear. For example, it's clear that in
his ontology, Spinoza is committed to the existence of particulars
alone (that is, roughly, things that cannot exist in many places at
the same time). It is also clear that, in his view, conceptual
generality - and in particular the operation of
*abstracting* from particulars - are rife with the
possibility of error. (For example, we can be led to overlook
differences among particulars [TIE SS76], or mistake the products
of our own abstraction for "real beings", when in fact the
resulting ideas present only mind-dependent "beings of
reason" [*Metaphysical Thoughts* [= **CM**]
1.1; TIE SS93]). Finally, it's also clear that for Spinoza
ideas of universals and abstractions often have *lower*
epistemic value than ideas of particulars (e.g. TIE SS93).



These considerations have led some readers to take Spinoza to reject
*all* general and abstract ideas as inadequate (e.g. Curley
1973; Savan 1958). Such readings have trouble explaining
Spinoza's own reliance on words that seem to refer to general
concepts (such as *mode, idea, body*, etc.). In particular,
many of Spinoza's moral and socio-political doctrines -
and so the whole enterprise of the *Ethics* (see 1.4) -
seem to hinge on the validity of the general idea of "human
nature". Spinoza seems to believe that human beings share an
essential nature, even if they realize it to different degrees, and
hence also a common good. Here is a representative passage:



> 
> the greatest good of those who seek virtue is to know God,
> i.e....a good that is common to all men, and can be possessed
> equally by all men insofar as they are of the same nature (E4p36d; cf.
> E4p35, E4AppIX)
> 



One interpretative option here is to conclude that for Spinoza general
and abstract ideas such as "human nature" have only some
*pragmatic* value (cf. Carriero 2005). Spinoza clearly
recognizes usefulness as an epistemic good (for example, he describes
Aristotelian ideas of genera and species as handy mnemonic devices
[CM1.1]). On such a reading, it might not be strictly speaking true
that there is a common human nature, instantiated by each particular
human being; nonetheless, for ethical or political ends it might be
useful to invoke such an idea. But even this reading will have trouble
explaining how Spinoza can nonetheless insist that the "true
knowledge we have of good and evil" - again, hardly a
minor issue for an *Ethics* - is "abstract,
*or* universal" (E4p62s; G/II/257).



It helps to be precise about the nature of Spinoza's
*criticisms* of general and abstract ideas: falling short of an
epistemic ideal is not the same as utter inadequacy. Likewise,
mind-dependence is not the same as illusion or error. (Neither Leibniz
nor Kant, for example, would want to say that the idea or form of
space is an error or an illusion.) Finally, Spinoza's most
extensive criticism of general ideas, in E2p40s2, is not a criticism
of general ideas *simpliciter*, but only of most general ideas
derived from sense experience (cf. Bennett 1984). In Spinoza's
view, as finite and embodied beings whose minds are essentially ideas
of what happens to our bodies (2.2.1), we can't *avoid*
thinking in general terms. When our bodies interact with other bodies
- when we smell roses, or stub our toes - these encounters
leave impressions ("images") on our bodies; the finitude
of our bodies allows them to retain only a limited number of
*distinct* "images" since over time they get
overlaid and confused. The ideas we form by thinking the resulting
composite "images", and then predicate of indefinitely
many other entities - ideas such as *horse*,
*animal*, or *being* - represent distinctly only
what the bodies we happen to come across have in common insofar as
they can affect a human body. General ideas formed in this way are
just as "confused", inadequate and idiosyncratic, as any
other imaginative idea (see 3.2.2). So, contrary to what the
Aristotelians held, sense experience *doesn't* suffice
for true ideas of the essences of things. (Rather it gives rise to
unending philosophical controversies, as each one of us fashions
general types according to what we have experienced.)



Moreover, we also can't forget that, as we know from our
discussion of common notions (3.2.3), Spinoza doesn't think that
*all* general ideas grounded in sense experience alone result
in *confused* representations. Indeed, beyond this foundational
sphere of common notions, Spinoza seems to think of
"reason" on the whole as a necessarily *adequate*
way of forming general ideas:



> 
> it is clear that we *perceive many things and form universal
> notions*: I. *from* singular things which have been
> represented to us through the senses... II. *from*
> signs... These two ways of regarding things I shall henceforth
> call knowledge of the first kind, opinion or imagination. III.
> Finally, *from the fact that we have common notions and adequate
> ideas of the properties* of things...This I shall call reason
> and the second kind of knowledge (E2p40s2; emphases added)
> 



In other words, for Spinoza both (confused and inadequate) imagination
and (necessarily adequate) reason are ways of forming general ideas;
what distinguishes reason and imagination is in part the epistemic
value of their respective "universal notions". The general
ideas that belong to imagination are, as we have seen, confused and
inadequate and can lead us into error (3.2.2). The general ideas that
belong to reason - in particular, common notions and their
derivatives - are, like all ideas of reason, necessarily
adequate (3.2.3). The question that remains is whether Spinoza
recognizes any other rational and general "adequate ideas of
properties" beyond those implied by common notions.



(See also e.g. Newlands 2015, Hubner 2016.)


#### 3.2.5 Kinds of cognition III: Intuition



Spinoza characterizes *scientia intuitiva* as the kind of
cognition that "proceeds from an adequate idea of the formal
essence of certain attributes of God to the adequate knowledge of the
[NS: formal] essence of things" (E2p40s2). Given Spinoza's
claim that only infinite things can follow from infinite things
(E1p21-23), it seems that the "formal essences" of
particular things that intuition infers from the essences of divine
attributes must themselves be infinite (D. Garrett 2018:ch.7).



As noted above (3.2.3), Spinoza classifies intuition, alongside
reason, as intellectual rather than imaginative cognition. As such,
intuition is "necessarily true" (E2p41); allows us to
"distinguish the true from the false" (E2p42); is
"the same in all men" (E2p18s); and is cognition of things
"through their first causes" (E2p18s). Yet intuition also
clearly *exceeds* reason as an epistemic achievement in
Spinoza's eyes: it is intuition and not reason that he describes
as "the greatest virtue of the mind" (E5p25) and the
"greatest human perfection" (E5p27d), capable of affecting
the mind with a unique degree of force (E5p36s). Intuition is also the
only cognition on which Spinoza bestows the traditional honorific of
"*scientia*" (D. Garrett 2018:ch.7).



What is responsible for this singular place of intuition? Commentators
are divided. Some (e.g. Soyarslan 2016) propose that it allows us to
know truths that reason doesn't. Others (e.g. Nadler 2003) think
intuition is superior to reason as an epistemic *method* alone.
This latter interpretation is a natural way to understand
Spinoza's own mathematical illustration of the ways *all*
kinds of cognition, from imagination to intuition, can achieve the
same correct result (E2p40s2). Likewise, as many of Spinoza's
predecessors have also held, intuition is an *immediate*
knowledge, an insight "in one glance" (E2p40s2) into
essences. The principal superiority of intuition seems to stem from
the fact that it is in the business of cognizing *essences*
directly, without the mediation of ideas of mere *properties*
of things, whether "common" properties or other
"adequate ideas of properties", which form, as we have
seen, the foundations of reason (3.2.3).



(See also e.g. Carriero 2020, Primus 2017, Wilson 1999: ch.11.)


## 4. Eternity of the mind



Spinoza's doctrine of the eternity of the mind, one of last
subjects of the *Ethics*, has occasioned some of the most
impatient and uncharitable comments on the part of his readers (most
famously perhaps, Bennett 1984 describes it as "rubbish"
leading others to write rubbish). The cause for this impatience is
Spinoza's declaration that in Part 5 he will discuss "the
mind's duration without relation to the body" (E5p20s), a
declaration some see as a blatant violation of his commitment to
mind-body identity in Part 2 (E2p7s). But of course an identity of one
thing with another doesn't rule out the possibility of
*discussing* one but not the other, a procedure in which
Spinoza engages again and again (for example, in introducing the
possibility of ideas of ideas [see 2.3]). Spinoza is moreover quite
explicit that there is no eternity of human minds without a
corresponding eternity of bodies, and, far from contradicting any
commitments about mind-body relations made in Part 2, the doctrine of
the eternity of the mind in Part 5 arguably brings to light the full
meaning of those earlier commitments.



To recall (2.2.1), in Part 2 Spinoza proposes that the "first
thing" that constitutes this "actual being" of a
human mind is an idea of an "actually exist[ing]" body
(E2p11-13). Only in Part 5 does Spinoza clarify that
"actual" being or existence can be understood in two ways:
first, in the temporal or durational sense key to the claims made in
Part 2, and second, in an atemporal or purely ontological sense of
simply having being or reality at all (as opposed to, for example,
being merely possible):



> 
> We conceive things as actual in two ways: either insofar as we
> conceive them to exist in relation to a certain time and place, or
> insofar as we conceive them to be contained in God and to follow from
> the necessity of the divine nature. But the things we conceive in this
> second way as true, *or* real, we conceive under a species of
> eternity (E5p29s)
> 



Given these two senses of "actuality", Spinoza's
original claim in Part 2 that the "actual being" of the
human mind is an idea of an "actually exist[ing]" body can
also be understood in two ways. First, it can be understood as a claim
about what it takes for a human mind to begin existing in
*time*, as we have done in 2.2.1: any human mind starts to
actually exist in a durational sense when the nexus of bodily causes
in nature generates a new body, which then begins to be variously
affected or changed by external causes. The infinite intellect, in its
indefatigable omniscience, begins to represent these affections or
changes. The relevant "part" of God's omniscient
idea (see 2.1.2) is a new, temporally existing human mind. More
plainly put, a human "infant" is born, with "a body
capable of very few things, and...a mind...conscious of
almost nothing" (E5p39s).



This is the first, more intuitive sense in which human minds can be
said to "actually exist", the sense in which your mind
exists now when processing these words. But however much we may be
attached to our temporal selves and all that they feel, for Spinoza
there is another sense of "actual existence". In that
second sense, a human mind is still essentially an "actually
existing" idea of a certain "actually existing" bit
of extension. But the relevant bit of extension is not the living
human body, but its eternal *essence* - a certain
eternally possible way that divine extension can modify itself to take
on a certain ratio of motion and rest (cf. E2def[8]; G/II/100), i.e., a
certain determinate functional pattern of physical activity. In its
omniscience, the divine substance eternally understands itself as
being capable of being modified in such more determinate ways -
that is, of manifesting its own physical being as this or that snail
or sunflower or human infant. *Ideas* of these eternal bodily
essences are *eternal* "parts" of substance's
infinite intellect (E2p8). That is, for each bodily essence there is a
divine idea that "expresses the essence of the body under a
species of eternity" (E5p23s), as an eternal part of the
infinite intellect.



The eternal idea of a bodily essence is not only a part of God's
intellect (as all ideas are), it is also an eternal "part"
of the relevant *human* mind, a "part" that
"remains" (E5p23) even after the body's demise, when
there are no more ideas of bodily affections to be "felt".
This then is all there is also to human immortality, in
Spinoza's view: the eternal existence of the essences of our
bodies, and of ideas of those bodies. As Nadler emphasizes (2002), we
are far here from any traditional doctrine of personal immortality:
nothing that does not belong to us essentially, and nothing that
depends on sense experience, such as memories, persists beyond
death.



Spinoza attaches an *epistemic* challenge to this ontological
picture. He writes that we always "understand" and
"feel" "that we are eternal" (E5p23s):
presumably this means that we have some joyful, i.e., empowering
(E3p11d), intellectual grasp of our own eternity (even if we often
join these adequate ideas with inadequate ones [see 3.2.2], such as
*reward* or *punishment*). But he also suggests, prima
facie puzzlingly, that we can *increase* the degree of our own
eternity: "the more the mind understands things by the second
and third kind of cognition, the greater the part [*maxima
pars*] of it that remains" after the destruction of the body
(E5p38d). This suggestion might seem puzzling if we assume that the
"eternal part" of my mind is *just* the eternal
idea of the eternal essence of *my* own body. For then there
seems to be nothing that would be subject to improvement or
enlargement: my eternal essence just is my eternal essence.



But arguably this is not how Spinoza understands the eternal part of
the mind. The idea of the eternal essence of the body is just the
"first thing [*primum*]" (cf. E2p11) that grounds
my mind's eternal existence: it is the *foundation* of
eternal ideas of other things, just as the durational idea of this
body as changing is the foundation of imaginative ideas of other
things. "[T]he Mind is eternal, insofar as it conceives things
under a species of eternity" (E5p31s). Since for Spinoza any
human mind is essentially an idea of a certain "actually
existing" body, cognition of that body is the foundation of
*all* cognition whatsoever. This is true whether we are talking
about imaginative cognition of the external bodies we bump up against
in duration; or about intellectual cognition of eternally existing
essences: "Whatever the mind understands under a species of
eternity, it understands...from the fact that it conceives the
body's essence under a species of eternity" (E5p29). In
short, for Spinoza all cognition of eternal truths rests on a
cognition of our own body as an eternal essence. We can thus
understand the idea of enlarging or maximizing the eternal
"part" of our minds in terms of the number of eternal
truths, intuitive and rational, that we can acquire in the course of
our existence - or, as on innatist readings (see 3.1), the
number of eternal truths that we can make into *powerful*
"parts" of our minds.



(On consciousness, see 2.3; on imaginative cognition of the body see
2.2 and 3.2.2. On eternity of the mind, see also e.g. Garrett 2018:
ch.9. On Spinoza's debt to medieval Jewish views about
mind's eternity, see e.g. Klein 2014, Nadler 2002, Ravven and
Goodman 2002.)