broken instrument? Reason is only worth what its cause may be worth. If
man is the child of chance, his thoughts may be vain. If man is the
creature of a wicked and cunning being, the light of reason may be only
an _ignis fatuus_ kindled by a malicious and mocking spirit. Here is a
soul plunged in the lowest abysses of doubt; but it is a manly soul
which seeks in doubt a trial for truth, and not a comfortable pillow on
which slothfully to repose. How does Descartes upraise himself? By a
thought known to every one, and which was already found in St.
Augustine: "_Cogito, ergo sum_. I think, therefore I am." Deceive me who
will; if I am deceived, I exist. Here is a certainty protected from all
assault: I am. But what a poor certainty is this! What does it avail me
to have rescued my existence from the abysses of universal doubt, if
above the deep waters which have swallowed up all belief floats only
this naked and mortifying truth: I am; but I exist only perhaps to be
the sport of errors without end. The first step therefore taken by the
philosopher would be a fruitless one if it were not followed by a
second. An eye is open, and says: I see; but it must have a warrant that
the light by which it sees is not a fantastic brightness. No, replies
Descartes; reason sees a true light; and this is how he proves it: I am,
I know myself; that is certain. I know myself as a limited and imperfect
being; that again is certain. I conceive then infinity and perfection;
that is not less certain; for I should not have the idea of a limit if I
did not conceive of infinity, and the word _imperfect_ would have no
meaning for me, if I could not imagine perfection, of which imperfection
is but the negation. Starting from this point, the philosopher proves by
a series of reasonings that the conception of perfection by our minds
demonstrates the real existence of that perfection: God is. He adds,
that the existence of God is more certain than the most certain of all
the theorems of geometry. You will observe, Gentlemen, that the man who
speaks in this way is one of the greatest geometricians that ever lived.