## 1. Introduction: Rationalism and Substance




The seventeenth and early eighteenth centuries saw the heyday of
*metaphysical* system-building, but the expression
"continental rationalism" primarily connotes rather a set
of *epistemological* views. By contrast to British empiricism,
which traces all knowledge to sensory experience, these views
emphasize a reliance on reason (*ratio* in Latin, hence
rationalism), the resources of which are taken to be sufficient in
some sense for what we know. Thus, a signature doctrine of rationalism
is the doctrine of innate ideas, according to which the mind has built
into it not just the structure of knowledge but even its
content. Nonetheless, among the philosophers comprising the extension
of the expression, metaphysical issues, particularly the ontology of
substance, occupy the central place. Certainly, this is true of
Leibniz and Spinoza, but also of Malebranche and other Cartesians, and
even of Descartes on some plausible understandings of him.




To understand the relationship between rationalism's
metaphysical and epistemological commitments, it is helpful to recall
Plato's divided line, which establishes a parallel between
objects known and the means by which they are known. In fact, the
order of objects, the *ordo essendi* ranging in importance down
from the Good to other forms, to individual things, and to images, and
the order of knowing, the *ordo cognoscendi*, ranging from
intuition of various sorts down to sensory experience, is itself to be
found in various versions among the later rationalists. The important
point, in any case, is that, for the continental rationalists as for
Plato, the epistemological distinctions are grounded in ontological
distinctions. Or, to put it in terms that reflect rationalist thinking
on a number of issues, there is only a distinction of reason between
the two orders. The orders of being and knowing are not really
distinct; they differ only in our ways of thinking about them.




There is a good explanation of the close connection seen by the
rationalists between the epistemological and ontological orders, one
that also accounts for their notable reliance on reason. It derives
from their answer to what Leibniz called the grand metaphysical
question: why is there something rather than nothing at all? There is
something because there must be something; there cannot be nothing (and
this way of putting it shows the ultimate debt of the rationalists to a
tradition that goes back to Parmenides). Reality, or at least some part
of it, has necessary existence, and that necessity is something like
logical necessity. With this answer, a whole philosophical outlook
falls into place. First of all, any significant role for sensory
experience falls away, since what exists can be known *a priori*
by logic alone. Causal connections tend to be viewed as logical
connections; a principle of sufficient reason falls out which tends to
be read as a matter of logical deduction. One result is that there is
an impulse toward monism: if the ultimate cause must exist, then that
for which it is the sufficient reason must also exist, and just how the
two can be distinguished becomes problematic (again, the Parmenidean
antecedent is clear).




This outlook was not articulated as such by any rationalist except,
perhaps, Spinoza--indeed most were concerned to avoid such
consequences of their views. But the outlook does capture the
intuitions behind the metaphysical systems they elaborated. And it
certainly draws the contrast between them and the empiricists, who
tended toward *tychism*, the view that the world is largely, or
even entirely, a product of chance. On the empiricist account, the
universe consists of many independent individuals, which, if they are
connected, are so only accidentally, reducing causation to nothing
more than a matter of constant conjunction. (This physical,
metaphysical, and logical atomism is in the tradition of Democritus,
Epicurus, and Lucretius.) Under such circumstances, only experience of
the world can provide knowledge of it.




The early modern period of philosophy, including continental
rationalism, is generally supposed to have been driven by the new
science to a radical departure from the Aristotelianism of the late
medieval or renaissance period immediately preceding it. (But see
Goldstone's 1998 problematization of the very idea of early
modernity, and of the view that the period was launched by the New
Science.) The mechanization and mathematization of the world demanded
by the inertial physics of a moving Earth led to a revolutionary
philosophy better described, at least in its rationalist version, as
Platonic, or even Pythagorean. Even so, Aristotelian concepts and
terminology persisted. Both were appropriated and deployed to deal
with the new problems. The principal Aristotelian concept taken over
by the rationalists was the concept of substance.




Aristotle's term *ousia* is usually translated as
"substance". What exactly Aristotle meant by the term is a
thorny matter, much debated in the literature. His account of
substance in the *Categories* holds individual things, which he
terms "proper substances", to be paradigmatic of
substance. On this account, substance is best understood by analogy
with a grammatical subject--it takes a predicate, and is not
predicable of anything further. Thus, while animal is predicable of
horse, and horse of Bucephalus, Bucephalus stands by himself,
impredicable of, and hence, numerically different from anything
else. Much of Aristotle's account in
the *Metaphysics*--written years later--seems to
accord with this. However, *Metaphysics* (1017b10-26)
complicates the story. Aristotle there describes four uses of the
term. He concludes by reducing these to two broad senses--(1)
substance as *hypokeimenon*, the ultimate substratum, which is
not predicated of anything further; and (2) substance as form--
that which makes each thing the kind of thing that it is. Indications
within the text suggest that, by the time that he was giving the
lectures that are collected in the
*Metaphysics*, Aristotle regarded not individual things but the
matter of which these individual things are formed as the ultimate
subject of predication. On this conception, there is some sense in
which Bucephalus is himself predicable of matter. Thus, while the
substance of the *Categories* serves as a principle of
individuation, the substance of the *Metaphysics* is more
complicated, serving both to individuate Bucephalus and Seabiscuit and
to capture the connection or sameness that holds between them.




That substance should be called upon to account for both difference
and sameness in the world indicates an inherent tension in the
concept. Certainly, the two senses of the term
'substance' were in tension during the seventeenth
century. The momentum of rationalist argument was to resolve the
tension by folding the first sense into the second: there is no real
differentiation in the world, only the appearance of
difference. Seventeenth century rationalists assigned to substance
three roles of connection. Substance was taken (1) to connect
attributes as attributes of the same thing *at a time* (a given
shape and a given size as the shape and size of the same thing), (2)
to connect them *over time* (the later shape and size, perhaps
different from the earlier, as nonetheless the shape and size of the
very same thing), and (3) to connect them as somehow related to the
thing as a certain kind of thing (for the Cartesians, shape and size
would indicate the thing to be of the kind "extended").
However, Spinoza alone among the continental rationalists fully
embraced the conception of substance as a fundamental connection
between things. The other members of the movement struggled to retain
a notion of substance as individuator, but did so with varying degrees
of success.


## 2. Descartes and His Critics




The rationalism of the most famous of the rationalists is problematic
on two counts. First, Descartes is known as the father of modern
philosophy precisely because he initiated the so-called
epistemological turn that is with us still. Since Descartes,
philosophy has been especially concerned with the theory of knowledge,
both in itself and as it affects other areas of philosophy. Ethics,
for example, has often been concerned with how the good might be known
rather than with what the good might be. With his fundamental
objective of achieving certainty for his beliefs, Descartes has thus
been principally responsible for the incomplete characterization of
rationalism as not just etymologically but essentially connected to
the claims of reason. While Descartes certainly sought to justify the
claims of reason and relied upon them, even for him there are
corresponding ontological views that are no less important to his
system.




The second problematic aspect of Descartes's rationalism is more
difficult to resolve. Descartes was a radical voluntarist who thought
that all truth, including what we take to be necessary truth, depends
on the will of God. Care needs to be taken in how this view is
expressed, for Descartes did not hold simply that what we take to be
necessary in fact is contingent. He held that actually necessary truth
depends on God's unconstrained will, such that even propositions
that are logically contradictory might have been simultaneously
true. Reason itself thus seems no longer reliable, and experience
would seem to be the only way of determining which of the worlds even
beyond logic such a powerful and unconstrained God has created. Not
many of the rationalists, even among the Cartesians, followed
Descartes in this radical voluntarism, and some in recent times have
seen the view as ultimately incoherent. Even so, Descartes seems to
have taken the view as the basis at least of his physics, and perhaps
of his whole system. Indeed, on some accounts, it was this doctrine of
created truth that enabled Descartes to frame the most radical doubt
hitherto conceived, when in the *Meditations* he entertained
the possibility that he was always deceived by a mendacious deity,
even when considering what appeared to him most obviously true, to
wit, the existence of the "simplest things" that are the
subjects of arithmetic and geometry. (Against this view, Margaret
Wilson (1982, 105-114), observes that, in Meditation 1, God need
only have the power to deceive me about the eternal truths, not to
create them.) While a doubt (and a doctrine) this radical might lead
one to despair of ever achieving sure knowledge, for Descartes, it was
the catalyst for his discovery of the *cogito*, and with it,
his first indubitable truth--the truth of his own existence.




At every stage of Descartes's argument in
the *Meditations*, there are ontological implications: the
mind's independence of sensory perceptions (perceptions whose
reliability is ultimately upset by the possibility that he is
dreaming), the literally unimaginable sort of thing that a physical
object such as a piece of wax must be, the existence of a veracious
God, who provides a guarantee for the reliability of reason, and
finally the existence of a physical world consisting of extended
things. Arnauld immediately suggested to Descartes that his argument
contained a circle: we can rely on reason only if we know that God
exists, but we know that God exists only by relying on reason. Thus,
Descartes has established the certainty only of his own existence, but
nothing beyond that. Descartes thought that he had a response to this
criticism, but whether he did, and how cogent it is as a rebuttal,
have been perennial questions of debate among Descartes scholars. One
way to understand Descartes's procedure is that while he does
not claim to prove even that he exists, he does claim to show that it
is unreasonable to think otherwise. That is, he shows that the
argument of the skeptic fails because the consistent application of
reason leads to the view not that reason is unreliable, but precisely
the opposite. The skeptic might be right, but he is unreasonable. A
parallel case in the moral realm might be brought out here. Over the
course of an exchange with Mesland about the nature of human freedom,
Descartes notes that we can, absolutely speaking, act against against
our reason and judgment. However, morally speaking, we cannot (CSM III
245/AT 4:173). When explaining what he means by this, Descartes
suggests that we can only act against our better judgment and reason
in the case where we take it to be a good thing to demonstrate our
freedom by doing so. This is what Kenny has called the "freedom
of perversity" (Kenny 1998). In other words, only with the
attitude of perversion can we act against what we take to be best. So,
as in the epistemological realm, so too in the moral realm: it is
unreasonable or even perverse to deny the results of the consistent
use of reason. Descartes thus emerges at least as a bootstrap
rationalist--using innate reason and a disinclination to
perversity to assert the truth of his own existence, which, in turn,
serves as a foundation for a more extensive search after
truth--in a way that mirrors the non-absolute status of his
necessary truths. The rationalist connection between the orders of
being and knowing is thus preserved.




But what sense can be made of the doctrine of created truth? By what
kind of causality did God create the eternal (necessary) truths? In
response to this very question Descartes replied that God did so in
just the way that He created everything else, that He is the total and
efficient cause not only of the existence of created things, but also
of their essence. The eternal truths are just this essence of created
things. As before, Descartes did not elaborate his answer, but, once
again, he provided enough elsewhere for us to do so. It is clear that
for Descartes, as for many other theologically orthodox thinkers, the
existence of things results from an unconstrained exercise of God's
omnipotent will to create *ex nihilo*. What Descartes might be
saying, then, is that an eternal truth or essence is also something
that is created *ex nihilo*. The eternal truths might thus be
instances of what Descartes called substance.




In the *Principles*, Descartes defined "substance"
as a thing that exists such that its existence does not depend on any
other thing. He immediately added that, strictly speaking, the term
applies only to God, who, as uncreated, alone depends on nothing else
to exist. However, he allowed that in an extended sense it applies to
things that depend only on God's creation and continuing
conservation. These created substances are really distinct from other
substances insofar as they are conceivable apart from each other. They
do not require a subject of inherence, and are thus ontologically, if
not causally, independent. These created substances are distinguished
from other things, such as qualities, which not only depend on God
causally, but also depend ontologically on other things, ultimately on
created substances, as subjects of inherence. In this sense, a created
substance for Descartes is like the *hypokeimenon* of
Aristotle, playing both its roles, as individuator and bearer of
qualities. However, with his definition of the real distinction, he
built in an unintended tendency toward monism--a tendency that
Spinoza exploited. For Descartes, one thing is really distinct from
another just in case it can be conceived apart from that other. But,
if this test of independence is applied to causal relations, it
produces the result that there is but one substance, God.




What types of things counted as created substances for Descartes?
Clearly, he takes an individual mind to be a created substance. If a
mind did not have this status, then Descartes's argument for its
immortality, that it can be conceived apart from all else except God,
and *a fortiori* from the body, would collapse. Beyond minds,
however, an ambiguity appears. Although there are texts in which
Descartes speaks of individual things like a piece of wax as
substances, there are others--most famously, the Synopsis to
the *Meditations*--that indicate that there is but a
single extended substance, of which individual things are the
modes. At a minimum, there is an asymmetry in his treatment of minds
and material things, perhaps reflecting the tension between
a *hypokeimenon*, accounting for difference, and the other
sense of *ousia*, accounting for sameness. To say that Peter
and Paul are substances is to say that their minds are numerically
distinct; but to say that a piece of wax and a piece of wood are
substances might be to say that they are both extended things.




However many instances of each kind there might be, there is a
dualism of two kinds of substance, according to Descartes: thinking
things, or minds, and extended things, or bodies. This dualism
generated two well-known problems, resolved by Descartes with only
partial success. One of his most incisive critics, Elisabeth of
Bohemia, wanted to know how in voluntary action the will, which is a
property of the unextended mind, could have an effect on the body,
given that, according to Descartes's mechanistic physics, a material
thing can be affected only by what is in contact with it. Descartes
replied with a rather mysterious account of how the mind and body
formed a unique kind of composite. Over the course of the letters of
their correspondence that focus on this issue, Elisabeth presses
Descartes for an explanation of *how* mind and body interact.
Descartes's responses do not satisfy Elisabeth, and rightly so.
For, the mysterious composite that he suggests involves the concept of
a *primitive notion* (Shapiro, 65/AT 3:665), a concept that is
not present in any other of his writings. Descartes states that we have
primitive notions for the body, "extension", for the mind,
"thought", and for the mind/body composite,
"union." He explains that each of these notions is best
understood by using a faculty that is particularly well-suited to grasp
it. The primitive notion for the mind, he states, is best understood by
the understanding alone; the primitive notion of the body is best
understood by the understanding aided by the imagination; and the
primitive notion of the composite is best understood by the senses
(Shapiro, 69/AT 3:691). Armed with the distinction in methodology for
knowing each of these notions, Descartes diagnoses Elisabeth's
difficulty in understanding his explanation in the following way: She
is trying too hard to understand the union of her mind and body by her
understanding alone. The remedy to this problem, he suggests, is for
the Princess to stop meditating on the problem, and to instead focus on
"life and ordinary conversations" in order to conceive the
union (Shapiro, 70/AT 3:692). But, of course, this recommendation does
not adequately address Elisabeth's question. For, while focusing
on "life" and "ordinary conversations" may well
help to conceive *that* the mind and body interact, a point that
Elisabeth does not call into question, it furnishes nothing towards an
answer to the question of *how* such an interaction occurs. The
discussion of this topic comes to an end with Elisabeth's
suggestion that she is better able to understand the *how* of
interaction by thinking that part of the soul is extended (Shapiro,
72/AT 4:1). On this model, a necessary condition for motion, contact,
is possible.




Descartes's effort to resolve a second difficulty is more promising,
and also exemplifies the rationalistic character of his thought. The
problem is to show how the mind can know something such as a material
thing that is different in kind from it, given a longstanding principle
that only like can know like. He rejected this essentially Aristotelian
principle, but still had to give an account of such knowledge. From
scholastic sources, Descartes was able to construct a theory of ideas
according to which to know something is to have an idea of it, the idea
being the very thing known in so far as it is known. He saw the term
"idea" as ambiguous: taken materially, it has formal
reality, as a mode of the mind; taken in another sense, it has
objective reality, as the thing represented. But there is no real
distinction between these realities, only a rational distinction. They
are really the same thing considered differently. A welcome
epistemological upshot of this rationalist gambit is that Descartes has
no skeptical problems generated by ideas standing as a *tertium
quid* between the knower and what is known.




This result is indicated by Descartes's use of the term, picked up
and emphasized by Malebranche, according to which there are no
*false* ideas; every idea in this sense is materially true in
that it has an object, and that is the object it appears to have. This
conception of an idea is the basis for Descartes of what has been
called the transparency of mind: I cannot be mistaken that I am
thinking about what I am thinking about. Malebranche (whose entire
philosophy was colored by his struggles with Descartes's theory
of ideas), in fact, later erected such incorrigible intentionality
into the fundamental principle of his epistemology. Meanwhile,
Descartes's view that material or formal reality and objective
reality are only rationally distinct might be taken to mean that minds
are intrinsically intentional. A mind just is the sort of thing whose
states are about something else. Arnauld extended this thesis, which
adumbrates later thinkers such as Brentano, to include all mental
phenomena, even sensations.




Another line of discussion that relates to the problem of dualism and
the nature of ideas is advanced in 1734 by Ghanaian philosopher Anton
Amo. An extraordinarily interesting thinker in his own right, Amo
advances a critique of Descartes's assertion that the mind can
sense, that is, that the immaterial mind can passively receive sensory
information. In his dissertation, *On the Apatheia of the Human
Mind*, *or The Absence of Sensation and the Faculty of Sense in
the Human Mind and Their Presence in our Organic and Living Body*,
Amo states that the human mind is spirit, and that spirit is that
substance that is purely active. Following the narrative of the
commitment to the metaphysical reality of substance as the common
feature of rationalists through this period, Amo sits firmly in the
rationalist camp. But it is on the basis of this particular definition
of substance that Amo distinguishes his view from
Descartes's. According to Descartes, the mind can sense. For
Amo, sensation, which is purely passive, cannot be a feature of the
spiritual, purely active substance of mind. There are two threads of
Amo's critique. First, he is concerned to uphold the soul in the
lofty position that it deserves given its status as purely active. His
critique of Descartes on this point intersects with the objections
raised by Elisabeth: the mind, being immaterial, cannot interact with
material things. Thus, the mind cannot have sensation of material
objects (Amo, 75). Second, Amo wishes to emphasize the essential
nature of the body for human beings. On his view, "to live and
to have sensation" are inseparable predicates. All living things
feel; all feeling things live. But, on his view, "to live"
is to be embodied. This allows Amo to call into question
Descartes's claim, in *Meditations* II, that he is
nothing but a thinking thing. For Amo, it is impossible for the
"thinking thing" to live without a body. Amo is thus a
dualist, like Descartes, but with the important difference of removing
sensation from the mind, and locating it in the body. This move
simultaneously preserves the pure activity of the mind and boosts the
importance of the body in the entity that is a human being.




But Amo's dualism faces the same problem as Descartes's:
if we accept the fact that the body senses and the mind does not, then
Amo must provide an explanation for how the mind and body communicate.
In particular, he must provide an explanation for how the body can
sense, for instance, pain, and communicate this sensation to the
purely active mind. While Amo might seem no better situated than
Descartes to offer such an explanation, he does endorse an interesting
definition of "idea" that may provide a starting point for
such an explanation. Amo states that when we think of the manner in
which a human being functions, there are four elements that must be
kept separate: mind, the operation of the mind, idea, and immediate
sensation. Both the mind and its operations are immaterial, he says,
and immediate sensation is a property of body. However, on Amo's
view, "idea" is to be understood as "a composite
entity; for there is an idea when the mind makes present to itself a
sensation pre-existing in the body, and thereby brings the feeling
before the mind" (Amo, 74). If by "composite", Amo
means a composite of material and immaterial substance, then this
suggestion bears some resemblance to Elisabeth's claim, above,
that she thinks that there could be a material part of the soul that
could account for its ability to interact with the body. Of course,
explaining just how the mind makes a sensation present to itself and
thus brings a feeling before it, will determine the success of any
such explanation.


## 3. Malebranche and Cavendish




The battle between the Cartesians and their opponents in the latter
half of the seventeenth century was one of the great struggles in the
history of philosophy, but it was one in which the lines were not
clearly drawn. For, although those in the Cartesian camp claimed the
banner of Descartes, there were as many differences among them as
between them and their opponents. Perhaps the most important
difference among them hinged on whether or not they accepted
Descartes's doctrine of created truth. Desgabets and his student
Regis were the most important among the few who did accept the
doctrine. Along with their acceptance of the doctrine, however, came
nascent tendencies toward empiricism. On the other hand, Malebranche,
the most notable among the Cartesians who rejected the doctrine of
created truth, developed a philosophical system with a purer
rationalistic character than Descartes's own. Descartes had
advised his followers to follow not him but their own
reason. Malebranche, like other heterodox Cartesians, justified his
differences from Descartes as the result of following this
injunction. On his view, his rejection of the doctrine of created
truth followed from his commitment to other, deeper views in
Descartes. He thus represented himself as more Cartesian than
Descartes himself.




The philosophy of Malebranche is sometimes portrayed as a synthesis of
Descartes and Augustine, but a more precise way to put this relation
is that Malebranche used Augustine to rectify shortcomings he
perceived in the philosophy of Descartes. Chief among these was
Descartes's theory of ideas, which, according to Malebranche,
not only fails to reflect human beings' proper dependence on God
but also leads inevitably to skepticism. Initially, Malebranche
thought that he agreed with Descartes's theory, but in the long
debate over the nature of ideas he had with Arnauld, who held a close
version of Descartes's theory, Malebranche came to see a need
for a different account.




Not implausibly, Arnauld took Descartes's claim about the
ambiguity of the term "idea" to mean that
"idea", or "perception", refers to one and the
same thing, a thing which stands in two different relations. Insofar
as it is related to what is known, it is called an idea; insofar as it
is related to the mind, it is called a perception. This (act of)
perception he took to be related to the mind as a mode of it. It is at
this point that Malebranche detected the threat of skepticism. What we
know, indeed what we know in the most important instances of
knowledge, is universal, necessary, and infinite, as in the case of
certain mathematical knowledge. But nothing that is the mode of a
particular, contingent and finite mind can be universal, necessary or
infinite. If ideas were modes of the mind, then we would not have such
knowledge; but since we do have such knowledge, ideas must be
something else. Malebranche argued that the only being in which such
ideas could exist is God. Following Augustine, he took ideas to be the
exemplars in the mind of God after which He creates the world. This
construal had the additional advantage for Malebranche of guarding
against skepticism because, although idea and object are no longer
identical, they are nonetheless necessarily connected as exemplar and
exemplum. Even so, it remained true for Malebranche that, when we look
at a material thing, what we in fact see is not that thing but its
idea. This is the core of his view of "vision of all things in
God", which he welcomed as an indication of human beings'
dependence on the deity. The immediate vehicle whereby we have such
knowledge is a particular, contingent, and finite mode of the mind;
but the universal, necessary, and infinite object of that mode can
exist only in some other kind of being. How are these ideas known to
the mind if they are not in it, at least not as modes of it? Although
ideas are not innate to the mind, for that would make them modes of
it, they are nonetheless always present to it. In seeking to know,
whether we realize it or not, we are consulting Reason, which
Malebranche identifies with the second person of the Trinity,
the *logos* of Neoplatonic theology. Our effort to know is a
"natural prayer" that Reason always answers.




As for individual substances, Malebranche clearly thought that every
material thing and every mind is a substance in the sense of a
*hypokeimenon*. But when pressed late in his life to show how
this status for them comported with the rest of his system, how they
could be anything but modes of a single substance, in short how he
avoided the drift into Spinozistic monism, he was in fact hard
pressed. In the *Search After Truth*, Malebranche clearly
committed himself to the view that everything is either a substance or
a mode. In addition, he accepted Descartes's criterion for a
substance that it be conceivable apart from everything else. However,
he maintained that any given portion of extension is conceivable apart
from the rest of extension and is thus a substance. (Descartes did not
think this, otherwise void space would be possible for him.) Since
extension is conceptually divisible to infinity, Malebranche is
committed to an infinite number of extended substances. Apart from the
whole of extension, moreover, every substance contains an infinite
number of substances, of (each of) which it is a mode. It is also a
part of an infinite number of substances, which are modes of it. The
explanatory value of the concept of substance would seem to have been
lost with such results as these. Malebranche's view seems to be
a degenerate version of Descartes's texts to the effect,
surprising but coherent, that there is but one material
substance, *res extensa*, whose modes are particular material
things. Here the effect is to reverse the Aristotelian logic of
substance. To say of \(x\), a particular thing, that it is extended
\(E\), is to say not that a substance \(x\) has a property \(E\), but
that \(x\) is a mode of
*res extensa*.




These difficulties in accounting for substance on Malebranche's
part seem to derive from his Platonism. As a Platonist, he was
interested less in substance as the *hypokeimenon*, which
accounts for difference, than in its other sense of *ousia*,
which accounts for sameness. Thus, Malebranche's skid to
Spinozism is greased even when he talks about mind, the essence of
which is thought--not this or that thought, "but
substantial thought, thought capable of all sorts of modifications or
thoughts". Since the same substantial thought is had by all
possessed of a mind, Malebranche's view smacks even of the
single intellectual soul for all human beings of the Latin
Averroists. In this sense too, then, his heterodoxy as a Cartesian is
part and parcel with his deep commitment to rationalism, and in
particular with his rationalistic reduction of phenomenal difference
to real sameness.




The final rationalistic aspect of Malebranche's thought that
deserves attention here is his theory of causation. For Malebranche, a
cause is that between which and whose effect there is a necessary
connection. On his view, the causal connection that is characterized by
this kind of necessity is that between God's will and its effects.
Thus, for Malebranche, only God has causal efficacy. What we take to be
real causes--for example the motion of a billiard ball that
collides with another that then begins to move--are in fact only
occasional causes, the occasions for the operation of the only real
cause.




A cousin of Malebranche's occasionalism is worth noting here.
Margaret Cavendish agrees with Malebranche that bodies do not cause
change in one another, but she disagrees with him about whether nature
is self-moving. Where Malebranche takes created things to possess no
causal power at all, Cavendish takes them to possess the power of
self-motion. On her view, when bodies interact, there is no transfer
of motion. Cavendish's commitment to this view is grounded in
her belief that properties cannot be transferred between
bodies. Because motion is a property, she argues, motion cannot be
transferred between bodies. Following this line of reasoning, when
bodies come into contact, they act as occasional causes, that is,
causes that merely occasion a change. In an interaction, one body will
serve as occasional cause, and the second body will serve as a
"principal" cause, which brings about, in itself, the
 appropriate effect (see Detlefsen 2006 and the entry on
 Cavendish).
 Both thinkers also hold the view, ubiquitous in the period, that motion
is issued into the created world as a result of God's willing it.
Cavendish is careful to note that this issuance is the result not of
"an immediate action of God" but rather by an
"all-powerful command" (Cavendish, 209). She rejects the
former option on the grounds that such continual, immediate action is
unsuitable to "an immovable and immutable essence"
(Cavendish, 209). On this point, she and Malebranche are in
agreement.




The difference in the way that they conceive of occasional causation
is in how they understand the content of the "all-powerful
command" that introduces motion into the system. On
Malebranche's view, a true cause is one where we can perceive a
necessary connection between it and its effect. The only candidate for
such a connection is between the infinite will as cause, and its
effects. Moreover, he seems to also endorse the claim that for a cause
to bring out its effect, it must possess the knowledge of how to bring
it about. In the case of the relationship between a finite mind and
the body to which it is joined, our ignorance of how the mind
"causes" the body to move is enough to deny that there is
causal connection. In short, only God has the required knowledge to
effect these kinds of changes. These arguments undergird the central
Malebranchean commitment: the utter dependence of all created things
on God. As such, it makes sense, on his system, to deny causal
efficacy to anything other than God. Such a denial of causal efficacy
entrenches the dependence of created things on their creator.




Cavendish tells a different kind of story here. She notes that those
who show discomfort with the notion that God, through His command,
gave the power of self-motion to all created things, are clouded by
their "ambition" (Cavendish, 209). Ambition leads certain
thinkers to imagine that the immaterial substance of their souls is
the only created thing that possesses self-motion. On this
understanding of causation, they feel closer to God, who is radically
self-moving, and superior to material things, which do not possess the
ability to self-move. However, Cavendish notes, the decree from God
that introduces motion into the created world is just as easily
imparted to material things as to immaterial things. As such, there is
no reason to suppose that He did not give the power of self-motion to
material things.




Cavendish's criticism of those whose ambition clouds the way
they think about self-motion does not apply to Malebranche, however.
For, on his view, no created thing, human souls included, possesses
the power to self-move. Given Malebranche's combined
rationalistic and theological commitments, none of this is
surprising. The surprise, or at least irony, comes when
Malebranche's arguments that natural causes--even and
especially human volitions--cannot be real causes cross the
channel and are deployed by Hume. The radical empiricist account of
causation that Hume gave in terms of constant conjunction is just
Malebranche's rationalist occasionalism without the role
assigned to God. For Hume, Malebranche's occasional causes are
the only causes.


## 4. Spinoza




The centrality of substance for the continental rationalists is
further borne out by the importance of that concept for Spinoza,
especially within his *Ethics*. Spinoza devoted the entire
first part of that work to a consideration of substance, or, as he
also termed it "*Deus sive Natura*" ("God, in
other words, Nature"). The remaining parts trace the
consequences of his conception of substance for epistemology,
psychology, physics, and ethics. While Spinoza's account of
substance is quite rightly regarded as a development and working-out
of Descartes's metaphysics, there are also (as with Descartes
and Malebranche) considerable, and important, differences between the
two. What is important for our present purposes, however, is that (as
with Malebranche) Spinoza's departures from Descartes are almost
always the manifestation of a form of rationalism purer than
Descartes's own. Most radically, Spinoza replaced
Descartes's substance pluralism with a monistic account modelled
on Cartesian extended substance. Just as, in some places, Descartes
treats bodies as mere modes of a single extended substance, so, for
Spinoza, all individuals--both bodies and minds--are modes
of a single substance.




Spinoza arrived at this position by way of a decidedly uncartesian
account of attributes. While Descartes held that two substances of the
same type can share the same principal attribute, Spinoza rejected
this. Any two substances, argued Spinoza, must be distinguished either
by their attributes (Spinoza dropped the modifier
"principal") or by their modes. But, since modes are
themselves both ontologically and causally dependent on the substances
of which they are affections, they cannot be the individuating
principle for them. Thus, it must be the attributes themselves that
individuate substances (and not just *types* of substances, as
Descartes argued). Similarly, while Descartes held that each substance
is characterized by one and only one principal attribute, Spinoza
invoked the principle of plenitude to show that substance must have
infinite attributes. Based on a variation of the ontological argument,
he maintained that substance is pure, utterly unlimited being. It must
therefore, he argued, possess infinite attributes, in the dual sense
of possessing unlimited attributes and of possessing *all*
attributes. Since substance is characterized by infinite attributes,
and since no two substances can share a single attribute, there can be
only one substance. This radical monism was repugnant to many who,
like English philosopher Anne Conway, saw that it eliminated any and
all distinction between the creator, God, and His creation.




Spinoza's one substance is at the farthest possible remove from
Aristotle's proper substances. Whereas, for Aristotle,
individual things, such as Bucephalus, are paradigmatic substances,
Spinoza denies their substantiality. But does this mean that, unlike
Aristotelian proper substances, which are not predicable of anything
else, Spinoza's finite modes are predicable of substance?
Scholars are divided on this point. Curley has argued that Spinoza
retains the conception of the substance-mode distinction as a
distinction between independent and dependent being, but rejects the
view that the substance-mode distinction correlates to the distinction
between a subject of predication and its predicate. Bennett, however,
argues that Spinoza does indeed regard finite modes as predicable of
substance, or, as he puts it, as "adjectival on the
world". Bennett characterizes Spinoza's account of
substance as a "field metaphysic" in which individual
things are simply clusters of qualities within regions of space. Just
as a blush is merely a confluence of properties on a region of a face,
so the face--indeed, the person whose face it is--is a
confluence of properties "on a region" of substance.




Whether or not Spinoza rejected the predicability of finite modes, it
is clear that he did not regard them as either causally or
conceptually independent in the way that is requisite for substance.
For Spinoza, substance is "in itself and is conceived through
itself", whereas a mode is "in something else and is
conceived through something else". The "in itself/in
something else" aspect of these two definitions captures
Descartes's conception of causal independence, while the
"conceived through itself/through something else" aspect
refers to Descartes's conceivability-apart criterion for
ontological independence. Descartes, it will be recalled, regarded
divine substance as both causally and ontologically independent, but
created substances as ontologically, but not causally, independent,
since they depend on God's creative (and conservative) power for
their existence. It is in this sense that, for Descartes, the term
"substance" is used equivocally for God and created
substances. Spinoza, however, denied that "substance" is
an equivocal term. In so doing, he eliminated two asymmetries in
Descartes's metaphysics--that between divine and created
substance, and the asymmetry between extended and thinking substance
that Descartes expresses in the Synopsis to
the *Meditations*. For Spinoza, finite minds are not themselves
substances, but rather modes of thinking substance. That is, for
Spinoza, at the most fundamental level, all minds reduce to the
thinking substance of which they are affections.




Spinoza's account of the eternal verities marks a similar
rationalistic advance over Descartes's metaphysics. For Spinoza,
God is just substance simpliciter. He lacks volition and personality;
his only characteristics are pure being, infinity, necessity, and
activity. While Spinoza agreed with Descartes that God is the cause of
all things, he regarded him not as a transeunt cause, creating the
universe "from the outside" through an act of will, but as
an immanent cause, from whom the universe unfolds out of his own
necessity. For Spinoza, all things therefore follow by logical (and
not merely causal) necessity from God's eternal and infinite
nature. In this sense, not only mathematical truths but indeed such
apparently contingent facts as Caesar's having crossed the
Rubicon are necessary truths for Spinoza. The difference between them
is not the necessity of the truths themselves but rather the route
that we take to arrive at them. While mathematical truths, for
instance, are deducible by reason alone, Spinoza recognized that the
finitude of human understanding prevents, or at least impedes, our
similarly deducing empirical facts about the world. In contrast with
some empiricists, who regard cause and effect as mere constant
conjunction, for Spinoza, the relationship between cause and effect
has the force of a logical entailment; empirical facts are themselves
necessary truths. The universe is thus, in principle at least,
perfectly intelligible to reason.




For Spinoza, as for Descartes, the metaphysical commitment to
substance underwrote a rationalist epistemology that strongly
privileges reason and intuition over sensation and imagination. The
distinctive character of Spinoza's epistemological rationalism
is rooted in his principle that "the order and connection of
ideas is the order and connection of things". For Descartes, the
mind and the body are, though intimately connected, radically
heterogeneous. How it is that the mind comes to know things about the
physical world therefore remains, despite his best efforts, a somewhat
murky business. By rejecting the substantiality of both minds and
bodies, and by regarding them both as modes of a single substance,
Spinoza obviated this difficulty. For Spinoza, the mind and the body
are the very same thing conceived in two different ways. Persistent
clusters of qualities in space are bodies. The ideas--or, in
Descartes's terminology, the objective reality--of these
bodies are minds. Just as a single body has a corresponding objective
reality, so collections of bodies characterized by various relations
also have a corresponding objective reality with isomorphic parts and
relations. Since there is no gap between minds and bodies, there is
therefore no difficulty in principle in perceiving the physical
world. On Spinoza's account, we perceive the physical world in
two ways--(1) by perceiving the actions of our own bodies, and
(2) by perceiving the effects of other bodies on ours. Thus, when
one's body runs, the correlative ideas are in one's mind.
Likewise, when someone steps on one's toe, the physical effects
on the toe likewise have their counterparts in the mind's
ideas.




Despite the necessary connection the mind has with the body, argued
Spinoza, sensation and imagination are inherently limited. The idea of
substance qua substance must be a perfect unity. However, the idea
which constitutes the human mind is complex--not a unity but a
plurality of ideas. That idea is therefore confused, rather than clear
and distinct. Clear and distinct understanding, on Spinoza's
account, must partake of the unity of the idea of substance, and not of
the fragmentary nature of the idea of the human body and its
affects. This cognitive unity is achieved in two ways--through
reason (which Spinoza termed "knowledge of the second
kind") and through intuition ("knowledge of the third
kind"). When we cognize through sensation and imagination
("knowledge of the first kind"), we try to grasp many
ideas at once, and thereby produce confusion. Reason and intuition, by
contrast, provide us with access to just one idea--the
substantial unity underlying our body and our mind. Reason does this
from "the fact that we have common notions and adequate ideas of
the properties of things", while intuition proceeds "from
an adequate idea of the formal essence of certain attributes of
God". To understand the substantial unity that is the necessary
cause of our body and our mind is to grasp them *sub specie
aeternitatis*.




This epistemological ideal forms the core of Spinoza's rationalistic
ethics--and, hence, on one plausible account, the core of his
*Ethics*. Spinoza's monism entails that the sort of
individuals that Aristotle regarded as primary substances are
distinguished not by their own substantial unity, but by their
conatus--their striving to persist. Thus, self-preservation is
not just one possible goal of ethical agents; it is the very thing
that makes those agents individuals. Our essence, and our ethical
task, is thus to be active, whereas, by contrast, to be passive
threatens our persistence. The mind persists through activity and is
threatened by passivity. It is therefore in our self-interest to
pursue adequate ideas through knowledge of the second and third
kinds. The more we join our minds with God through adequate knowledge
of things under the form of eternity, the less we are affected by
external things and, hence, by our own passions, which are nothing but
our passivity in the face of forces external to us. Adequate knowledge
of God gives us equanimity and calm, and literally ensures our
persistence. Ethical virtue is thus fundamentally epistemological. For
Spinoza, the most rationalist of figures discussed here, the good life
is the utterly rational life.


## 5. Leibniz and Conway




As we have seen, rationalist epistemology is grounded in a
metaphysical commitment to substance. The concept of substance allowed
the rationalists to reduce all complexity and plurality to an
underlying simplicity and unity, versus the empiricists, who, in their
skepticism about substance, were committed to regarding reality as
fundamentally plural and complex. Spinoza's metaphysics marked
the culmination of this rationalist momentum. In Leibniz, the last
great continental rationalist, we see its final movement. Leibniz,
like other rationalists before him, regarded quotidian things as
phenomena that ultimately reduce to perfectly simple
substances. However, for Leibniz, there is an infinite number of these
simple substances, each of them causally and perceptually isolated
from all of the others. Leibniz reasoned that this is the best of all
possible worlds because it balances the maximal possible complexity
with the maximal possible order. In thus privileging neither unity nor
plurality, neither simplicity nor complexity, and in striking the
balance that he did on purely rational principles, Leibniz exemplified
a more complex, more comprehensive and, ultimately, more mature
rationalism than that of his predecessors.




For Leibniz, at the most fundamental level, reality is characterized
by simple substances, or "monads", a term that Leibniz
picked up from Francis Mercury van Helmont and Anne Conway in 1696
(Merchant 1979). Since there are composites, Leibniz argued, there
must be simple substances that, together, constitute these
composites. Being simple, monads have neither parts, nor extension,
nor form, nor divisibility. Leibniz saw them as the "true Atoms
of nature". While Leibniz thus retained a strong commitment to
substance, he resisted rationalism's synechistic momentum, which
privileged the metaphysical and methodological stance of the
continuity of the universe, by rehabilitating substance's
Aristotelian role as an individuator. However, while, for Aristotle,
Bucephalus is a proper substance, Leibniz regarded Bucephalus not as a
substance but as himself comprising a collection of simple
substances. Leibniz agreed with Aristotle's characterization of
substance as the grammatical subject of predication and not itself
predicable of anything else. However, he complained that this account
does not go far enough. For Leibniz, the essence of substance lies not
in the fact that it is the subject of predication, but in the fact
that every possible predicate may be asserted or denied of it. In this
way, every individual substance has a complete concept, a conception
so complete (that is, so fully determinate) that every fact about the
substance, and about its situation in the universe--past, present
or future --follows from it analytically.




Leibniz's insistence that every individual substance has a
complete concept entailed that, unlike Spinoza, he regarded Cartesian
thinking substance and not Cartesian extended substance as
paradigmatic of substance. Descartes's extended substance (like
Spinozistic substance) is, on Leibniz's account, not a substance
at all since it does not afford a principle of individuation. Leibniz
argued that, whereas a real substance has a complete concept, the
Cartesian notion of extended substance is an abstraction arrived at
through an incomplete concept. Matter on its own is insufficient to
form or to constitute a substance. For Leibniz, a body could never be
a candidate for substance since bodies are susceptible to alteration
and are infinitely divisible. We can thus never arrive at a body of
which it can be said, "Here really is an entity."
Moreover, whereas Cartesian extended substance is totally inert,
Leibniz insisted that activity is the hallmark of substance. Anything
that acts is a substance; every substance constantly and
uninterruptedly acts. For Leibniz, this position follows from
God's perfection. God's planning of the universe was so
perfect that it only required to be set in motion by him. True
substances (that is, *entia per se*) are active and
self-causing. On Leibniz's account, God would lack all dignity
were he the sole cause in the universe--that is, if occasionalism
or interventionism were necessary. God's perfect planning
avoids the necessity for (continual or continuous) extraordinary
concourse. Thus, God's perfection entails that all substances
are active; passive extension is only matter, not substance.




The activity, or *appetition*, that Leibniz regards as
characterizing the monads is intimately bound up with his Principle of
Sufficient Reason. For Leibniz, a monad contains its whole history
because each monadic state (except for those states--creation is
paradigmatic of these--that are the result of divine causation)
has its sufficient cause in the preceding state. In turn, the present
state is the sufficient cause of all succeeding states. Despite this
emphasis on the inherent activity of substance, Leibniz, like Spinoza,
rejected the possibility of transeunt causation among substances.
Monads are "windowless" and neither admit nor emit causal
influence. Moreover, being thus windowless, monads can no more receive
perceptions from the world than they can any other external causation.
Rather, a monad's perceptions are built-in at creation. By
preestablished harmony, these perceptions perfectly align with the
universe's infinite monadic states. This entails that while
there is no genuine transeunt causation at the monadic level, a kind
of pseudocausation results from monads' harmonized perceptions
of each other as their respective appetitions convey them through
successive changes. For Leibniz, causal relations thus reduce to
logical relations in that every change in a substance follows from its
concept.




While Leibniz's view that every substance has a complete concept
reinforces the centrality of reason in his epistemology, in doing so,
it seems to undercut human and even divine volition, and thereby to
slide toward Spinozism. If every fact about Julius Caesar, and indeed,
every other fact about the universe is rationally deducible from the
Roman Dictator's complete concept, then it would seem that only
one course for the universe is possible. However, this is not a step
that Leibniz was willing to take. Were there no distinction between
contingent and necessary truths, argued Leibniz, fatalism would be
true, and human liberty of the will would be impossible. Leibniz
sought to avert this result by distinguishing between hypothetical and
absolute necessity. Absolute necessity, he argued, is governed by the
principle of contradiction. Something is absolutely necessary if its
negation is logically impossible. Hypothetical necessity, on the other
hand, describes a state of affairs that is necessary *ex
hypothesi*--that is, just in case a particular antecedent
holds--but not logically necessary. On Leibniz's account,
the fact that Caesar crossed the Rubicon is only hypothetically
necessary; it follows necessarily from the existence of the individual
substance that is Caesar, but its denial is not logically
impossible. According to Leibniz, God at creation conceived of an
infinite array of possible worlds. The myriad contingent facts of each
of these worlds are only hypothetically necessary. That is, they would
only be necessary if God were to instantiate that world. Since the
present world is the one that God chose to instantiate, all of the
contingent facts of this world are certain. However, they are
nonetheless contingent since their negation implies no absurdity. That
is, there was no logical impossibility preventing Caesar from deciding
not to cross the Rubicon. In this sense, his will--and, indeed,
human will generally--is free. Leibniz's argument for
hypothetical necessity has an obvious antecedent in Descartes's
doctrine of created truth. However, unlike Descartes, Leibniz limited
the doctrine's scope to contingent truths. He nonetheless hoped
to avoid Spinozist necessitarianism. Whether or not he succeeded in
doing so is a matter of debate in the literature.




Inasmuch as it characterizes the universe as composed of a plurality
of individual existences, none of which has any genuine causal
efficacy over any other, Leibniz's position shows considerable
affinities with Hume's empiricism. However, while Hume inferred
from this the importance of experience, Leibniz instead took this
ontology to preclude adventitious knowledge. He thus remained
committed on metaphysical grounds to the doctrine of innate ideas. In
his rejection of transeunt causation among substances, Leibniz
rejected the notion that we can learn new things about the world in
the sense of gaining new ideas that do not already exist in our
souls. On Leibniz's account, the temporal coincidence of a
certain phenomenon with one's "learning" of the
phenomenon was preestablished at creation in the same way that all
monadic states were. Leibniz admitted that it is idiomatically
acceptable to speak about acquiring knowledge via the senses. However,
he regarded all sensory reports as reducible to, and explicable as,
descriptions of logical relations. Leibniz's theory of knowledge
thus relegates the Aristotelian idea of human beings as blank slates
who learn through induction to a mere *facon de
parler*. By contrast, he strongly endorsed Plato's doctrine
of recollection to the extent that it locates all knowledge in ideas
already residing in the soul. Socrates's exchange with
Meno's slave boy, argued Leibniz, shows that the soul already
possesses the ideas upon which truths about the universe depend, and
needs only to be reminded of them.




On Leibniz's account, substances have built into them
perceptions of the whole universe. Every substance, he argued, is a
mirror of the whole universe to the extent that everything that has
ever happened or existed or will ever happen or exist are included in
its complete concept. The perceptions of all substances, he
maintained, thus resemble God's infinite perception in their
unlimited scope. It is with respect to clarity and distinctness that
the perceptions of created substance fall short of God's. For
Leibniz, the best of all possible worlds is that world that balances
the maximal possible complexity with the maximal possible order. The
existing world satisfies this through the infinite variety of
perspectives taken by the monads. By the principle of order, each
monad reflects the very same world as do the other monads. However, by
the principle of complexity, the monads reflect the world from an
infinite number of unique perspectives. This infinite variety in
perspectives entails that each monad reflects all of the others with
varying degrees of clarity and distinctness. In this way, the universe
is replete with an infinite number of different representations of
God's works. Among these, only God's perceptions are
universally clear and distinct. While the complexity requirement for
the best of all possible worlds would seem to preclude in principle
the possibility of human beings achieving knowledge of the
universe *sub specie aeternitatis*, Leibniz made a special
exception for human souls. On Leibniz's account, all monads have
low-level perceptions, of the kind that we experience when we are in a
stupor. However, the souls of living things have, over and above this,
feelings and memories. Human souls have, besides this, through divine
election, the power of reason. It is reason that allows us to
understand the universe as a system, through the use of models and
idealizations, and thereby to grasp the eternal truths. In this way,
argued Leibniz, human minds are not only mirrors of the universe of
created things, but indeed mirror God himself.




Leibniz is committed to the view that, given God's perfection,
anything God creates must also be perfect--this is why the
created world is the best possible world. This means that a large part
of his writings are theodicean in spirit. Leibniz shares this spirit
with his close contemporary, Anne Conway. Conway's system is
motivated by her desire to reject Cartesian dualism, Spinozism, and
Hobbesian materialism. On her view, any commitment to the existence of
material substance is a commitment to the existence of "dead
mass". Any such view is gravely mistaken. For, she holds that
nature is shot through with the "vital principle of
motion", which has life and perception, qualities befitting any
creation of God (Chapter IX, section 2). Conway thus rejects
Descartes's dualism, while nevertheless noting that because he
accepts the immateriality of God, he is at least better than Hobbes,
who holds that God is material. Finally, she registers that her
disagreement with Spinoza has to do with his monism, which effaces any
distinction between God and creatures (Chapter IX, section 3).




To avoid the problem that she identifies with Descartes and Hobbes,
Conway asserts a monism: all creatures are composed of one kind of
substance--spiritual. To avoid the problem she associates with
Spinoza, Conway asserts that while only one (spiritual) substance
exists, the universe is divided into three "species" that
differ in their essences: creatures, Christ, and God. This tripartite
separation is grounded on the basis of the changeability of the
member(s) of the species: the essential feature of creatures is that
they can change for the better and for the worse, the essential
feature of Christ is that he can only change for the better, and
God's essence is that He is unchanging (Chapter VI, section
4). In postulating these three "species" of the one
substance, Conway is able to assert God's separation from
creation, as well as a metaphysically and morally mediating role for
Christ. This mediating role for Christ is of central importance to
Conway's theodicy. On her view, accepting this tripartite
division of species "will contribute greatly to the propagation
of the true faith and Christian religion among Jews and Turks and
other infidel nations" (Chapter VI, section 5). This is because
once we appreciate the reasoning in favor of a mediator between
creatures and God, and we accept this reasoning, we believe in Christ
whether we call the mediator by that name or not. In this way, Conway
can answer a particularly difficult challenge to any Christian
thinker: how can Christianity be the universal religion, in which
salvation depends on knowing Christ, when so much of the Earth's
population is ignorant of Christ? On her system, she can assert that
many people may know Christ as mediator, without knowing him by name
or even by role in the Christian religion.




While the rise of British empiricism and of Kant's critical
philosophy marked the end of continental rationalism as a movement,
the elegant visions of Leibniz and Conway are a fitting paean to the
movement and, indeed, to the power of human reason.


## 6. Beyond Continental Rationalism: Other Voices




Since the early twentieth century, "continental
rationalism" has been profitably juxtaposed with "British
empiricism". The juxtaposition turns on the notion that the
rationalist views that were popular on the "continent"
were contemporaneous with the empiricist views that dominated the
philosophical conversations in Britain.




While the demarcation between rationalism and empiricism may be useful
as an interpretive and pedagogical tool, it should be borne in mind
that it is a construction in retrospect. The distinction between
*Empirici* and *Dogmatici* is traceable from ancient
Roman medicine to Baconian (both Roger and Francis) philosophy of
science. While Kant and his early commentators imported the
distinction into philosophy, the terminology of
"rationalism" and "empiricism", and the
association of these terms with, respectively, the Continent and
Britain emerged at the end of the nineteenth century (Aaron Wilson,
16-20).




In recent years scholars have problematized both the general
rationalist/empiricist distinction and the "continental
rationalism"/"British empiricism" divide. As Norton
has shown, the "British" in "British
Empiricism" can be called into question when we take notice of
the important role played by the French philosopher Pierre Gassendi in
the propagation of empiricist thinking in the period (Norton 1981).
Indeed, British philosophers in the relevant historical period were
far less disconnected from the Continent than they are
today. Philosophical crossings from Britain were frequent and
fruitful. In particular, Locke, Berkeley, and Hume all crossed the
Channel. Further, Loeb (1981) argues with some plausibility that the
rationalist-empiricist divide neglects strong rationalist strands in
Locke's and Berkeley's thought. Increasingly, scholars of
the early modern period (but again, recall Goldstone's critique
of early modernity as a periodization) are looking outside the bounds
of the rationalist/empiricist distinction in order to more accurately
capture the intersections and divergences present in the constellation
of ideas in the period.




Indeed, problematizing the distinction between continental rationalism
and British empiricism offers benefits beyond the possibility for
greater interpretative nuance and accuracy. In earlier sections of
this entry, we troubled the association of rationalism with the
Continent by considering British philosophers Margaret Cavendish and
Anne Conway alongside Malebranche and Leibniz, and Ghanaian
philosopher Anton Amo alongside Descartes. A focus on seventeenth and
eighteenth century rationalists, broadly conceived, as opposed to
*continental* rationalists in particular, makes possible the
inclusion in the conversation of other figures--notably, women
and non-Europeans--who did not live on the Continent but who mark
nodes of influence and importance in rationalist thought. Thus, an
additional strong motivation to call the distinction into question is
in an effort to include other voices in this period.




Before we consider two final rationalist women philosophers from
Britain, a brief digression is in order on the degree to which
rationalism permitted the philosophical participation of women (and to
a lesser extent of racialized others).




It is by now a familiar trope that rationalism excludes women.
Genevieve Lloyd famously argues that Descartes's
reconceptualization of reason as an attainment, and as an attainment
achieved by pure mind uncorrupted by sensuality and society,
unintentionally (but significantly) excludes women--whose
domestic roles inevitably involved the sensual and the social (Lloyd
1984/1993, 40-51). Susan Bordo characterizes Cartesian
"objectivism and mechanism" as a "*flight*
from the female cosmos and 'feminine' orientation towards
the world" (Bordo 1987, 100, emphasis in the original). Whether
or not rationalism constitutively excludes women, it is clear that
some individual rationalists do so. See, for instance, Hasana
Sharp's argument that Spinoza sees the better but does the worse
in his assertion in the
*Political Treatise* that women are naturally unequal to men
(Sharp 2012).




Against the characterization of rationalism as excluding women,
Margaret Atherton draws on Mary Astell and Damaris Lady Masham to
argue that in fact rationalism offered a framework in which women
(and, one presumes, members of non-European cultures) could do
philosophy. By prescribing a method of reasoning that doesn't hinge on
a particular education or social standing, argues Atherton (after
Astell), rationalism reconceptualizes reason as in principle possible
for all humans--man and woman, Plow-man and Doctor (Atherton,
32). Erica Harth traces the history of sixteenth and seventeenth
century French "salon women" and offers evidence that
Descartes's clear, jargon-free French and commitment to being
intelligible by lay people made Cartesianism appealing to the women
who regularly participated in philosophical salons. Further, Harth
reconstructs the thought of the prominent salon women to show that
they extend Cartesianism in novel ways (Harth 1991). However, she
notes that most of what comes down to us from French Cartesianism of
the day originated in the male-only academy, and not the salons.




Whatever the remaining legacy of Cartesian women in France, Astell
remains an important interpreter and proponent of Descartes's
epistemological method, a method she explicitly endorses as the basis
for supporting the education of, and philosophical inquiry by, women.
In her two-part 1694 and 1697 *A Serious Proposal to the Ladies:
Wherein a Method is offer'd for the Improvement of their
Minds*, Astell urges that meditation (in Descartes's sense
of that term) avails itself to all who apply themselves to it with
dedication. She admits that those (women or labourers, for instance)
whose circumstances do not permit them to contemplate truth may at
first find such contemplation unfruitful. However, she proposes
reading, discoursing, and serious meditation as remedies to this
situation. While Astell rejects the view that some people's
embodiment make them more suited for practical than intellectual
pursuits, she acknowledges that some reasoners' animal spirits
may incline them to volatility of thought; she therefore counsels
reasoners to withdraw their minds from their bodies and the material
world. Alice Sowaal identifies in Astell three central rationalist
themes: "an emphasis of the mind over the body; a theory of
innate ideas as the origin of knowledge; and a methodology that leads
the novice from confusion to clarity" (Sowaal). Astell bolsters
her Cartesian method with a theological argument that God would not
create naturally defective rational beings, and hence that all human
beings are capable of rational thought. If women are at first unable
to reason well, it is the result of their circumstances and not their
nature, she argues. Astell thus both draws on Descartes and
anticipates Wollstonecraft.




Relaxing the criteria for inclusion in the "rationalist"
camp also invites us to appropriately situate the rationalism of
Scottish philosopher Mary Shepherd. Shepherd was a sharp critic of
Hume's endorsement of the causal system we might call
"Malebranche without God". Shepherd raised her objections
to Hume's theory on the basis of her commitment to the
superiority of reason for knowledge, and in particular knowledge of
the truths of causation. Here we see that she shares at least one
characteristic of those typically ascribed to rationalists, the
exaltation of reason over the senses in knowledge acquisition. In
*An Essay Upon the Relation of Cause and Effect* (1824),
Shepherd seeks to dismantle Hume's causal theory of constant
conjunction by arguing that we can indeed have intuitive knowledge
that everything that exists requires a cause. Moreover, on her view,
it is reason, not "custom" or "habit", that is
our chief guide in the understanding of our daily lives (27-28).
Shepherd's critique of Hume is important in its own right as a
valuable contribution to the philosophical conversation of her age. It
is also, however, representative of the way that the rationalist
perspective was being articulated in the first quarter of the 19th
century. As such, it marks a moment in the history of rationalism.
Putting Shepherd into conversation with her fellow rationalists across
time only serves to deepen and broaden our understanding of this line
of thinking.




In sum then, while the notion of continental rationalism can be a
useful heuristic, especially for teaching and learning, it ought not
to be a strict criterion. A less restrictive conception of rationalism
not only supports a more historically accurate, nuanced understanding
of philosophical movements in the period; it also renders the
rationalist canon more diverse. As historians of philosophy
increasingly work to develop more inclusive canons, such a
reconceptualization is all to the good.