hat there is something
evident,--being a truth impressed on the mind and intellect,--and yet that
it cannot be perceived and comprehended. For how can you say distinctly
that anything is white, when it may happen that that which is black may
appear white? Or how are we to call those things evident, or to say that
they are impressed faithfully on the mind, when it is uncertain whether it
is really moved or only in an illusory manner? And so there is neither
colour, nor body, nor truth, nor argument, nor sense, nor anything certain
left us. And, owing to this, it frequently happens that, whatever they
say, they are asked by some people,--Do you, then, perceive that? But they
who put this question to them are laughed at by them; for they do not
press them hard enough so as to prove that no one can insist upon any
point, or make any positive assertion, without some certain and peculiar
mark to distinguish that thing which each individual says that he is
persuaded of.

What, then, is this probability of yours? For if that which occurs to
every one, and which, at its first look, as it were, appears probable, is
asserted positively, what can be more trifling? But if your philosophers
say that they, after a certain degree of circumspection and careful
consideration, adopt what they have seen as such, still they will not be
able to escape from us. First of all, because credit is equally taken from
all these things which are seen, but between which there is no difference;
secondly, when they say that it can happen to a wise man, that after he
has done everything, and exercised the most diligent circumspection, there
may still be something which appears probable, and which yet is very far
removed from being true,--how can they then trust themselves, even if they
(to use their own expression) approach truth for the most part, or even if
they come as near to it as possible? For, in order to trust themselves,
the distinctive mark of truth ought to be thoroughly known to them; and if
that be obscure or concealed, what truth is there which they can seem to
themselves to arrive at? And what can be so absurd a thing to say as,--This
indeed is a sign of that thing, or a proof of it, and on that account I
follow it; but it is possible that that which is indicated may either be
false, or may actually have no existence at all?

XII. However, we have said enough about perception. For if any one wishes
to invalidate what has been said, truth w