|
|
|
 
Descartes
How does Descartes try to extricate himself from the sceptical doubts
that he has raised? Does he succeed?
by Tom Nuttall
[All page references and quotations from the Meditations are taken from
the 1995 Everyman edition]
In the Meditations, Descartes embarks upon what Bernard Williams has
called the project of 'Pure Enquiry' to discover certain, indubitable
foundations for knowledge. By subjecting everything to doubt Descartes
hoped to discover whatever was immune to it. In order to best understand
how and why Descartes builds his epistemological system up from his
foundations in the way that he does, it is helpful to gain an
understanding of the intellectual background of the 17th century that
provided the motivation for his work.
We can discern three distinct influences on Descartes, three conflicting
world-views that fought for prominence in his day. The first was what
remained of the mediaeval scholastic philosophy, largely based on
Aristotelian science and Christian theology. Descartes had been taught
according to this outlook during his time at the Jesuit college La Flech_
and it had an important influence on his work, as we shall see later. The
second was the scepticism that had made a sudden impact on the
intellectual world, mainly as a reaction to the scholastic outlook. This
scepticism was strongly influenced by the work of the Pyrrhonians as
handed down from antiquity by Sextus Empiricus, which claimed that, as
there is never a reason to believe p that is better than a reason not to
believe p, we should forget about trying to discover the nature of reality
and live by appearance alone. This attitude was best exemplified in the
work of Michel de Montaigne, who mockingly dismissed the attempts of
theologians and scientists to understand the nature of God and the
universe respectively. Descartes felt the force of sceptical arguments and,
while not being sceptically disposed himself, came to believe that
scepticism towards knowledge was the best way to discover what is certain:
by applying sceptical doubt to all our beliefs, we can discover which of
them are indubitable, and thus form an adequate foundation for knowledge.
The third world-view resulted largely from the work of the new scientists;
Galileo, Copernicus, Bacon et al. Science had finally begun to assert
itself and shake off its dated Aristotelian prejudices. Coherent theories
about the world and its place in the universe were being constructed and
many of those who were aware of this work became very optimistic about the
influence it could have. Descartes was a child of the scientific
revolution, but felt that until sceptical concerns were dealt with,
science would always have to contend with Montaigne and his cronies,
standing on the sidelines and laughing at science's pretenses to knowledge.
Descartes' project, then, was to use the tools of the sceptic to disprove
the sceptical thesis by discovering certain knowledge that could
subsequently be used as the foundation of a new science, in which
knowledge about the external world was as certain as knowledge about
mathematics. It was also to hammer the last nail into the coffin of
scholasticism, but also, arguably, to show that God still had a vital r_le
to play in the discovery of knowledge.
Meditation One describes Descartes' method of doubt. By its conclusion,
Descartes has seemingly subjected all of his beliefs to the strongest and
most hyberbolic of doubts. He invokes the nightmarish notion of an all-
powerful, malign demon who could be deceiving him in the realm of sensory
experience, in his very understanding of matter and even in the simplest
cases of mathematical or logical truths. The doubts may be obscure, but
this is the strength of the method - the weakness of criteria for what
makes a doubt reasonable means that almost anything can count as a doubt,
and therefore whatever withstands doubt must be something
epistemologically formidable.
In Meditation Two, Descartes hits upon the indubitable principle he has
been seeking. He exists, at least when he thinks he exists. The cogito
(Descartes' proof of his own existence) has been the source of a great
deal of discussion ever since Descartes first formulated it in the 1637
Discourse on Method, and, I believe, a great deal of misinterpretation
(quite possibly as a result of Descartes' repeated contradictions of his
own position in subsequent writings). Many commentators have fallen prey
to the tempting interpretation of the cogito as either syllogism or
enthymeme. This view holds that Descartes asserts that he is thinking,
that he believes it axiomatic that 'whatever thinks must exist' and
therefore that he logically concludes that he exists. This view, it seems
to me, is wrong. It should be stated on no occasion, in the Meditations,
does Descartes write 'I am thinking, therefore I am', nor anything
directly equivalent. Rather, he says:
"Doubtless, then, that I existāand, let him deceive me as he may, he
can never bring it about that I am nothing, so long as I shall be
conscious that I am something. So that it must, in fine, be maintained,
all things being maturely and carefully considered, that this proposition
I am, I exist, is necessarily true each time it is expressed by me or
conceived in my mind." (p. 80).
The point here is that it is impossible to doubt the truth of the
proposition 'I exist' when one utters it. It is an indubitable proposition,
and one that will necessarily be presupposed in every attack of the
sceptic. Descartes is not yet entitled to use syllogisms as the
possibility of the malign demon is still very much alive. As an aside,
Descartes himself denies that the cogito is a syllogism, although it
should be mentioned that in some of the Replies to Objections he seems to
assert that it is in fact a syllogism. Finally, in the Regulae ad
directionem ingenii, Descartes denies the usefulness of syllogisms as a
means to knowledge.
I believe that, given Descartes' project, it is fair to grant him that the
cogito deserves the status he bestows upon it. For can there be anything
more certain than something that is so forceful and so powerful that every
time it is presented to our mind we are forced to assent to it?
What Descartes did here was to jiggle about the way philosophy normally
approaches the construction of knowledge structures. By starting with
self-knowledge, he elevates the subjective above the objective and forces
his epistemology to rest upon the knowledge he has of his own self (and
inadvertently sets the tone for the next 300 years of philosophy). This
leaves him with a problem. He can know his own existence, that he is a
thinking thing and the contents of his consciousness, but how can any of
this ever lead to any knowledge of anything outside of himself?
The answer is that, by itself, it can't. Descartes, in the third
Meditation, attempts to prove the existence of God, defined as a being
with all perfections. This proof is to be derived from his idea of a God,
defined as a being with all perfections. So far, so good - Descartes
examines the contents of his consciousness and discovers within it this
idea, and we can allow him this. At this point, however, he introduces a
whole series of scholastic principles concerning different modes of
causation and reality without proper justification:
"For, without doubt, those [ideas considered as images, as opposed to
modes of consciousness] that represent substances are something more, and
contain in themselves, so to speak, more objective reality, that is,
participate by representation in higher degrees of being or perfection
than those that represent only modes or accidents; and again the idea by
which I conceive a Godāhas certainly in it more objective reality than
those ideas by which finite substances are represented.
Now it is manifest by the natural light that there must be at least
as much reality in the efficient and total cause as in its effect; for
whence can the effect draw its reality if not from its cause? And how
could the cause communicate to it this reality unless it possessed it in
itself?"
Whence do these principles draw their indubitability? Even if we grant
that it is contrary to natural reason that an effect can have greater
'reality' than its cause, that the concepts of modes and substances are
coherent with Descartes' method, let alone possess the properties that he
ascribes to them, then surely we can still bring the malign demon into
play? Is it not possible that this all- powerful demon could bring it
about that Descartes has a notion of a being with all possible perfections
that he calls God? No, says Descartes, because the notion (representing
something perfect) would then have more objective reality than the demon
(as something evil and thus imperfect) has formal reality, and 'it is
manifest by the natural light' that this is not possible. But why not?
Maybe the demon has just made it seem impossible, and it seems that
Descartes has no answer to this.
Further problems remain. Cosmological arguments for God invoking the
notion of causation have always had to contend with the problem of the
cause of God. For if all events (or ideas) are caused ultimately by God,
then what about God Himself? Why should He be exempt from this rule? The
standard response to this is to claim that God, being omnipotent, causes
Himself. One of the chief perfections that Descartes attributes to God is
that of 'self-existence', that is, that His existence depends on nothing
else but itself. But if we examine this idea, it seems a little confused.
If God is the efficient cause of God then we are forced to ask how
something that does not yet exist can cause anything. If God is the formal
cause of God, i.e. it is part of the intrinsic nature of God that he
exists - which seems more likely - then it seems that we have merely a
reformulation of the ontological argument for God's existence from
Meditation 5.
It seems that Descartes may have anticipated the wealth of criticism that
the causal proof of God would inspire, and so, after explaining how human
error and a benevolent, non-deceiving God are compatible in Meditation
Four, he produced in Meditation Five a version of the mediaeval
ontological argument for God's existence. Unlike the causal argument, the
ontological argument doesn't involve the covert import of any new
principles. It simply purports to show that, from an analysis of his own
idea of God, Descartes can show that He necessarily exists. The reasoning
goes like this:
I have ideas of things which have true and immutable natures. If I
perceive clearly and distinctly that a property belongs to an idea's true
and immutable nature, then it does actually belong to that nature. I
perceive clearly and distinctly that God's true and mmutable nature is
that of a being with all perfections. Further, I perceive clearly and
distinctly that existence is a perfection and non-existence a non-
perfection. Thus existence belongs to God's true and immutable nature. God
exists.
One of the interesting things about this argument is that, at first sight,
it does not seem to depend in any way upon anything that has been proved
hitherto. It is an application of pure logic, an analysis of what we mean
when we say 'God' and a inference from that analysis. Descartes
explicitly says that an idea's true and immutable nature does not in any
way depend upon his thinking it, and thus upon his existence. Once he has
perceived clearly and distinctly that an idea's true and immutable nature
consists in such-and-such, that is the case whether or not he thinks it is,
or even if he exists or not. Descartes in fact recognises the primacy of
the ontological argument: "although all the conclusions of the preceding
Meditations were false, the existence of God would pass with me for a
truth at least as certain as I ever judged any truth of mathematics to
be." If this is true, which it seems to be, then this argument is only as
trustworthy as the faculties which enabled us to construct it, which are
the same faculties that enable us to know mathematical truths, and so it
seems worthwhile to ask how, under Descartes' theory, we come to know
mathematical truths. Descartes claims we perceive them clearly and
distinctly. How do we know that what we perceive clearly and distinctly is
true? Because God, being perfect, is no deceiver, and would not let it be
the case that we could ever perceive something clearly and distinctly
without it being the case. It seems then, that this proof of God, relying
on the veracity of clear and distinct ideas, relies on the certain
knowledge that a non-deceiving God exists. We have another proof of God,
the causal proof as described in Meditation three. But apart from the
patent futility of using one proof of p to construct another proof of p,
on examining the causal proof of God further, we find that it, too, relies
upon a methodology that can only be relied upon if the divine guarantee is
present, for if this guarantee is not present, then, as I mentioned above,
how can we be sure that the all-powerful demon is not exercising his
malignant influence?
This, of course, is the infamous Cartesian circle, first identified by
Arnauld in the Fourth Objections and discussed ever since. Many
philosophers have tried to get Descartes off the hook in various ways,
some by denying that there is a circle and some by admitting the
circularity but denying its significance. I will here briefly evaluate a
few of their arguments.
Some commentators have taken a passage from Descartes' reply to the Second
set of Objections (Mersenne's) to indicate that Descartes is only actually
interested in the psychological significance of fundamental truths. The
passage is as follows:
"If a conviction is so firm that that it is impossible for us ever to have
any reason for doubting what we are convinced of, then there are no
further questions for us to ask; we have everything we could reasonably
want."
Under my interpretation, this is what it is about the cogito that makes
it so important for Descartes, so we cannot have any argument with the
principle expressed by him in the above passage. But can it help break the
circle? When we clearly and distinctly perceive something, Descartes says,
fairly I think, that this perception compels our assent, that we cannot
but believe it. God's r_le in the system, to these commentators, is as a
guarantor of our memory regarding clarity and distinctness. In other words,
once we have proved God's existence, we can happily know that any memory
we have of a clear and distinct idea regarding x is true i.e. that we
really did have a clear and distinct idea of x. But this does not seem
satisfactory, as we still do not have a divine guarantee for the reasoning
that leads us from the clear and distinct notions we originally have about
God to the proof of His existence. We can give assent to the clear and
distinct notions we have originally; in fact, we are compelled to give
this assent when the notions are presented to our mind, but the logical
steps we take from these ideas to the final proof is still subject to the
evil demon because God is not yet proven. Furthermore, because these steps
are needed, the memory of the original clear and distinct ideas are
themselves subject to doubt because God is not yet proven. It seems that
the only way either of the proofs of God could be accepted would be if we
had an original clear and distinct perception of God directly presented to
our mind (qualitatively similar to the cogito). But this in itself would
make any future proofs redundant. Interestingly, this sounds quite similar
to a divine revelation.
Harry Frankfurt, in his book 'Demons, Dreamers and Madmen', has argued
that what Descartes is actually looking for is a coherent, indubitable set
of beliefs about the universe. Whether they are 'true' or not is
irrelevant. Perfect certainty is totally compatible with absolute falsity.
Our certainty may not coincide precisely with 'God's' truth, but should
this matter?:
"Reasonācan give us certainty. It can serve to establish beliefs in which
there is no risk of betrayal. This certainty is all we need and all we
demand. Perhaps our certainties do not coincide with God's truthāBut this
divine or absolute truth, since it is outside the range of our faculties
and cannot undermine our certainties, need be of no concern to us."
(Frankfurt, p 184)
This is almost a Kantian approach to knowledge, where we as humans only
concern ourselves with the phenomena of objects as they present themselves
to us, not with the objects in themselves. Can we ascribe this view to
Descartes? It's tempting, given what we have said above regarding the
prime importance of indubitability, but it would seem that a God
presenting ideas to us in a form which doesn't correspond to reality, and
then giving us a strong disposition to believe that they do correspond to
reality would be a deceiving God and contrary to Descartes' notion of Him.
Thus the belief set would not be coherent. Perhaps, as we do not have
clear and distinct ideas of the bodies we perceive, and as the divine
guarantee only extends as far as clear and distinct ideas, we are being
too hasty in judging that reality is how it appears to be and if we
stopped to meditate further we would see that reality is actually like
something else. But aside from the fact that this seems unlikely,
Descartes never seemed to envisage the possibility.
So much for the Cartesian circle. Where does this leave the ontological
argument, which we had only just begun to discuss? Aside from the
methodological difficulties, there do seem to two further problems with it.
The first has been noted by almost every student of Descartes over the
years - that of the description of existence as a property. Put briefly,
this objection states that existence is not a property like 'red' or
'hairy' or 'three-sided' that can be applied to a subject, and thus it
makes no sense to say that existence is part of something's essence. If we
assert that x is y, we are already asserting the existence of x as soon as
we mention it, prior to any application of a predicate. from the beginning.
In other words, to say 'x exists' is to utter a tautology and to say that
'x doesn't exist' is to contradict oneself. So how can sentences of the
form 'x doesn't exist' make sense? one may well ask. It is because these
sentences are shorthand for 'the idea I have of x has no corresponding
reality' and it was to solve problems like this that Bertrand Russell
constructed his theory of descriptions. To add existence to an idea
doesn't just make it an idea with a new property, it changes it from an
idea into an existent entity.
Finally, if Descartes is right, there seems no reason why we cannot
construct any other idea whose essence includes existence. For instance,
if I conjure up the idea of an existent purple building that resembles the
Taj Mahal', then it is the true and immutable nature of this idea that it
is a building, that this building resembles the Taj Mahal, that the
building is purple, and that it exists. But no such building does exist,
as far as I am aware, and if it did exist, its existence would not be
necessary, but contingent. This in itself is enough, I think, to show that
the ontological argument is false.
Once we have destroyed Descartes' proofs of the existence of God, the
edifice of knowledge necessarily comes tumbling down with them, as we
find that almost everything Descartes believes in is dependent on God's
nature as a non-deceiver:
"I remarkāthat the certitude of all other truths is so absolutely
dependent on it, that without this knowledge it is impossible ever to know
anything perfectly." (p.115)
The only possible exceptions are those assent-compelling beliefs such as
the cogito. Even these, however, are doubtful when we are not thinking
about them, and the above passage does give weight to Edwin Curley's
argument that:
"Descartes would hold that the proposition "I exist" is fully certain only
if the rest of the argument of the Meditations goes through. We must buy
all or nothing."
This is not the end of the story, though. As far as Descartes is concerned,
by the end of Meditation Five, he has produced two powerful proofs of God,
has a clear and distinct notion of his own self, has a criterion for truth,
knows how to avoid error and is beginning to form ideas regarding our
knowledge of corporeal bodies.. And so it remains only to explain why we
are fully justified in believing in corporeal bodies, and also to draw the
ideas of Meditation Two regarding self-knowledge to their full conclusion.
Regarding the nature of corporeal bodies and our knowledge of them, it
seems to me that, given his premises, the conclusions Descartes draws in
Meditation Six are generally the correct ones. He again invokes the causal
to argue that the ideas of bodies we have within our minds must be caused
by something with at least as much formal reality as the ideas have
objective reality. We could theoretically be producing these ideas, but
Descartes dismisses this possibility for two reasons - firstly, that the
idea of corporeality does not presuppose thought and secondly that our
will seems to have no effect on what we perceive or don't perceive. (This
second argument seems to me to ignore dreaming, in which what we perceive
derives from us but is independent of our will). The ideas, then, could
come from God, or from another being superior to us but inferior to God.
But this, too, is impossible, argues Descartes, as if it were the case
that God produces the ideas of bodies in us, then the very strong
inclination we have towards believing that the idea-producing bodies
resemble the ideas we have would be false and thus God would be allowing
us to be deceived which is not permissible. The same would apply if any
other being were producing these ideas. Thus, concludes Descartes, it is
most likely that our ideas of corporeal bodies are actually caused by
bodies resembling those ideas. We cannot be certain, however, as we cannot
claim to have clear and distinct notions of everything we perceive. We can,
however, claim certainty with regard to those properties of bodies which
we do know with clarity and distinction; namely, size, figure (shape),
position, motion, substance, duration and number (not all of these
assertions are justified). Obviously we cannot claim that we know these
properties for specific bodies with clarity and distinction, for to do so
would leave open the uestion of why it is that astronomy and the senses
attribute different sizes to stars. What Descartes means is that we can
be sure that these primary qualities exist in bodies in the same way that
they do in our ideas of bodies. This cannot be claimed for qualities such
as heat, colour, taste and smell, of which our ideas are so confused and
vague that we must always reserve judgement. (This conclusion is actually
quite similar to the one John Locke drew fifty years later in his Essay
Concerning Human Understanding.)
I think we can grant this reasoning, with the caveat regarding dreaming
that I noted above, and of course the other unproved reasonings that
Descartes exhumes here, such as the causal principle. Furthermore, it
seems to be further proof that Descartes does believe we can get to know
objects in themselves to a certain extent.
Finally, I turn to Descartes' argument for the distinction of mind and
body. Descartes believes he has shown the mind to be better known than the
body in Meditation Two. In Meditation Six he goes on to claim that, as he
knows his mind and knows clearly and distinctly that its essence consists
purely of thought, and that bodies' essences consist purely of extension,
that he can conceive of his mind and body as existing separately. By the
power of God, anything that can be clearly and distinctly conceived of as
existing separately from something else can be created as existing
separately. At this point, Descartes makes the apparent logical leap to
claiming that the mind and body have been created separately, without
justification. Most commentators agree that this is not justified, and
further, that just because I can conceive of my mind existing
independently of my body it does not necessarily follow that it does so.
In defence of Descartes, Saul Kripke has suggested that Descartes may have
anticipated a modern strand of modal logic that holds that if x=y, then L
(x=y). In other words, if x is identical to y then it is necessarily
identical to it. From this it follows that if it is logically possible
that x and y have different properties then they are distinct. In this
instance, that means that because I can clearly and distinctly conceive of
my mind and body as existing separately, then they are distinct. The
argument, like much modern work on identity, is too technical and involved
to explore here in much depth. But suffice to say that we can clearly and
distinctly conceive of Dr Jekyll and Mr. Hyde as being distinct and yet
they are identical, necessarily so under Kripke's theory. It is doubtful
that Kripke can come to Descartes' aid here and Descartes needs further
argument to prove that the mind and the body are distinct.
And so we finish our discussion of Descartes' attempts to extricate
himself from the sceptical doubts he has set up for himself. As mentioned
previously, the ultimate conclusion to draw regarding the success of the
enterprise that Descartes set for himself must be that he failed. When the
whole epistemological structure is so heavily dependent on one piece of
knowledge - in this case the knowledge that God exists - then a denial of
that knowledge destroys the whole structure. All that we can really grant
Descartes - and this is certainly contentious - is that he can rightly
claim that when a clear and distinct idea presents itself to his mind, he
cannot but give his assent to this idea, and furthermore, that while this
assent is being granted, the clear and distinct idea can be justly used as
a foundation for knowledge. The most this gets us - and this is not a
little - is the knowledge of our own existence each time we assert it. But
Descartes' project should not be judged by us as a failure - the fact that
he addressed topics of great and lasting interest, and provided us with a
method we can both understand and utilise fruitfully, speaks for itself.
Bibliography
1. Descartes, Ren_ A Discourse on Method, Meditations and Principles of
Philosophy trans. John Veitch. The Everyman's Library, 1995.
Descartes, Ren_ The Philosophical Writings of Descartes volume I and II ed.
and trans. John Cottingham, R. Stoothoff and D. Murdoch. Cambridge, 1985.
Frankfurt, Harry Demons, Dreamers and Madmen. Bobbs-Merrill, 1970.
Curley, Edwin Descartes Against the Skeptics. Oxford, 1978. Vesey, Godfrey
Descartes: Father of Modern Philosophy. Open University Press, 1971.
Sorrell, Tom Descartes: Reason and Experience. Open University Press,
1982.
The Oxford Companion to Philosophy ed. Ted Honderich. Oxford University
Press, 1985.
Cottingham, John Descartes. Oxford, 1986. Williams, Bernard Descartes: The
Project of Pure Enquiry. Harmondsworth, 1978.
Russell, Bertrand The History of Western Philosophy. George Allen and
Unwin, 1961. 11. Kripke, Saul Naming and Necessity. Oxford 1980.
Word Count: 4577
ADDITIONAL FEATURED ESSAYS
Descarte 2
How can we know if we are a brain in a vat? Can we be sure that we are not the playthings of evil demons? These question
Descartes Epistemology
is known as foundationalism. In his Meditations, Descartes tries to discover certain, indubitable foundations for knowle
Decartes
Descartes is famed by is familiar notion, “I think therefore I am (Cogito, ergo sum.).” It is a conclusion h
Critical Summary: Descartes' Meditations I, II, And VI
. In his First, Second, and Sixth Meditations, Descartes outlines and carries out part of his plan in search of the indu
Descartes Vs. Pascal
For centuries, human beings have been debating over the validity of the use of reason. This is a very, very difficult su
|
|
|
|
