And a bsolute sc epticism is easily shown to be
self-contradictory. For a theory of nescience, in
condemning all knowledge and the faculty of
knowledge, condemns, itself. If nothing is true,
or if nothing is known, then this theory itself is
not true, or its truth cannot be known. And if
this theory is true, then nothing is true ; for this
theory, like all others, is the product of a defective
intelligence. In whatsoever way the matter is put,
there is left no standing-ground for the human
critic who condemns human thought. And he
cannot well pretend to a footing in a sphere
above man's, or below it. There is thus one pre-
supposition which every one must make, if he is
to propound any doctrine whatsoever, even if that
doctrine be that no doctrine can be valid ; it is
the presupposition "tharTinowIedge is possible, and
that truth can be known. And this presupposition
fills, for modern philosophy, the place of the Cogito
ergo sum of Descartes. It is the starting-point
and criterion of all knowledge.
