d in the general constancy of the
order of nature--as hypothetical assumptions which cannot be proved, or
known with that highest degree of certainty which is given by immediate
consciousness; but which, nevertheless, are of the highest practical
value, inasmuch as the conclusions logically drawn from them are always
verified by experience.

This, in my judgment, is the ultimate issue of Descartes' argument; but
it is proper for me to point out that we have left Descartes himself
some way behind us. He stopped at the famous formula, "I think,
therefore I am." But a little consideration will show this formula to be
full of snares and verbal entanglements. In the first place, the
"therefore" has no business there. The "I am" is assumed in the "I
think," which is simply another way of saying "I am thinking." And, in
the second place, "I think" is not one simple proposition, but three
distinct assertions rolled into one. The first of these is, "something
called I exists;" the second is, "something called thought exists;" and
the third is, "the thought is the result of the action of the I."

Now, it will be obvious to you, that the only one of these three
propositions which can stand the Cartesian test of certainty is the
second. It cannot be doubted, for the very doubt is an existent thought.
But the first and third, whether true or not, may be doubted, and have
been doubted. For the assertor may be asked, How do you know that
thought is not self-existent; or that a given thought is not the effect
of its antecedent thought, or of some external power? And a diversity of
other questions, much more easily put than answered. Descartes,
determined as he was to strip off all the garments which the intellect
weaves for itself, forgot this gossamer shirt of the "self;" to the
great detriment, and indeed ruin, of his toilet when he began to clothe
himself again.

But it is beside my purpose to dwell upon the minor peculiarities of the
Cartesian philosophy. All I wish to put clearly before your minds thus
far, is that Descartes, having commenced by declaring doubt to be a
duty, found certainty in consciousness alone; and that the necessary
outcome of his views is what may properly be termed Idealism; namely,
the doctrine that, whatever the universe may be, all we can know of it
is the picture presented to us by consciousness. This picture may be a
true likeness--though how this can be is inconceivable; or it may have
no more resem