DESCARTES: MEDITATION 4
 The Fourth Meditation deals with an objection that arises out of the Meditator’s attempt
to prove God’s existence in the Third Meditation. But before we look at that, there is a classic
objection raised against the proof in the Third Meditation, initially voiced by Antoine Arnauld
in his Fourth Objections. It’s so famous it has a name: “The Cartesian Circle.” Here’s how
Arnauld puts it:
The only remaining scruple I have is an uncertainty as to how circular reasoning is to
be avoided in saying: the only secure reason we have for believing that what we clearly
and distinctly perceive is true, is the fact that God exists. But we can be sure that God
exists, only because we clearly and evidently perceive that; therefore prior to being
certain that God exists, we should be certain that whatever we clearly and evidently
perceive is true.
In short, the Meditator seems to appeal to what he is trying to prove in the course of his proof.
Whether he does in fact do so is a matter of controversy.
 The objection raised in the Fourth Meditation is that the proof of God’s existence proves
too much, since the guarantee that God would not give us a nature such as to be deceived seems
to rule out any deception at all. That’s surely too strong a claim: we are sometimes fooled, even
if we aren’t always fooled. Well, the Meditator’s strategy in the Fourth Meditation is to claim
that we are responsible for such cases of deception in virtue of misusing faculties that God gave
us. The moral is clear. If we do not misuse our faculties, then we will not be deceived. Not
surprisingly this turns out to be equivalent to the Clarity-and-Distinctness Rule, at least under
certain assumptions the Meditator is willing to make.
 Here’s the account. The Meditator notices that he has two distinct faculties: intellect and
will, the former concerned with understanding (perceiving, thinking, imagining, and so on), the
latter with willing (choosing, hoping, deciding, and so on). These faculties not only do different
things, they have different natures. The intellect is concerned only with thinking. As such, it
merely entertains or combines ideas, and “turns out to contain no error in the proper sense of
that term.” Furthermore, the Meditator is aware that his intellectual abilities are limited: there
are things he does not understand, his memory isn’t so great, his imagination can’t generate
an image of a thousand-sided regular polygon distinct from a thousand-and-one-sided regular
polygon. All that is to say: his intellect is ﬁnite and limited.
 (It is no failing on God’s part, the Meditator claims, that he was