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between particular doubts about particular intellectual perceptions,
and systematic doubt about all intellectual perceptions. His use of
these distinctions in answering the charge of circularity, and, relat-
edly, his attitude towards scepticism in these matters, can best be
brought out if we take up a connection on which he insists between
 having true knowledge and having a special kind of reason  so
strong that it cannot be knocked out by any stronger reason as he
puts it in the letter to Regius already referred to (III 65, K 74; and
cf. the passages of V Med. and II Rep. also cited on p. 165).
If we take some irresistible proposition Q, Descartes says first
that a person A has a reason of this kind for believing Q if he is
actually fully considering Q. In fact, it is not entirely clear that A
190 knowledge is possible
has a reason for believing Q which goes beyond his clear and dis-
tinct perception of Q: at any rate, there is nothing else more evident
than Q from which A derives Q or on which he bases it. But the
more important question is whether there is any reason that could
be brought against A s conviction. This question divides into two.
There is a psychological question, whether A in this state can be
made doubtful of Q; the answer to this is  no . There is a logical or
epistemological question, whether there are any good reasons
which could count against it, even though A while intuiting could
not appreciate them. These might be either particular or systematic
reasons for doubt. The first are reasons specially for doubting Q:
for instance, that it is inconsistent with some other proposition
with an equally good claim to be true. But if this were so, then there
would be some obscurity in A s perception, and A would not have
done his best in clarifying his ideas. Whether Descartes can consist-
ently admit that A might be in this position though A is convinced
that he is clearly and distinctly perceiving, is a question we shall
come back to shortly. The immediate point is that in the everyday
sense in which there is sometimes a good reason of a particular
kind for suspecting that A is confused with regard to something
that he thinks is self-evident, in that sense it is often the case that
there is no reason to suspect this. This parallels, for intellectual
perception, a point made in Chapter 2 about sense perception. In
the everyday sense in which there is a reason to doubt that some
apparently bent sticks are bent, there is no reason to doubt this of
others, and Descartes does not proceed by pretending otherwise: he
does not try simply to generalize the particular everyday doubts.
Similarly with intellectual perceptions, the question is not whether
in each case some particular kind of everyday reason might be
brought against A s conviction. The question is whether there
might be brought against it the other, systematic, kind of doubt, the
 very slight, so to speak metaphysical possibility that every such
conviction might, after all, be delusory.
But in fact no good reason of this kind can be brought, Descartes
claims, because God exists and is no deceiver. When A is not actu-
ally intuiting Q, he may be open to the consideration that system-
atic error is possible, and he may have no way of answering it.
knowledge is possible 191
Descartes holds that here it makes a difference whether A believes
in God or not (where belief in God is taken, of course, to include
appropriate reflections on the systematic implications of God s
being no deceiver). Descartes is consistent in claiming that, on his
views, it makes a difference. Presented with the systematic doubt,
the believer has a systematic answer, an answer which purports to
explain in general the validity of the perceptions being questioned.
The unbeliever has no systematic answer, has nothing to say to this
point. The sceptic will object that while the believer has  something
to say , this in itself is not enough  what is needed is that what he
has to say should express knowledge, and Descartes cannot claim
this without falling back into a circle. Confronted with this sceptic,
Descartes can only invite him to go through the proofs of God. If he
understands them and is sincere, Descartes believes, the sceptic
cannot but accept them:
the Sceptics . . . have never perceived anything clearly; from the mere
fact that they had perceived something clearly they would have ceased
to doubt and to be Sceptics.
(VII Rep.: VII 477, HR2 279)
If he accepts them, he will acknowledge that there is a general
reason to be brought against systematic doubt. If he accepts them
when intuiting them, and accepts that he did accept them when
intuiting them, but simply refuses to accept them when, and
because, he is not intuiting them, then it is appropriate to bring
against him the consideration which we have already examined,
that he is refusing a merely structural condition on having usable
knowledge.
The argument can be put summarily like this. When one is actu-
ally intuiting a given proposition, no doubt can be entertained. So
any doubt there can be must be entertained when one is not intuit-
ing the proposition. If this is a particular doubt, then it must be
dealt with by further intellectual inspection of this and other pro-
positions. If it is the general and systematic doubt, then we have a
general and systematic answer, the existence and benevolence of
God. If either a particular or a systematic doubt is raised against
192 knowledge is possible
that, then we can only turn to intuiting the proofs of it; Descartes
believes that the sceptic must, if he intuits those proofs, accept
them. If the sceptic then reverts to objecting merely because he is
no longer intuiting, we can point out that the use of propositions
one is not at that instant intuiting (the rule (A)) is a minimal
structural condition on getting on at all, and that just as it would be
unreasonable to spend all one s time rehearsing one intuition, so it
would be unreasonable to spend all one s time rehearsing the [ Pobierz całość w formacie PDF ]