although I do not open my eyes or move from my place, and even,
perhaps, although I have no body: but, if I mean the sensation
itself, or consciousness of seeing or walking, the knowledge is
manifestly certain, because it is then referred to the mind, which
alone perceives or is conscious that it sees or walks. [Footnote: In
the French, "which alone has the power of perceiving, or of being
conscious in any other way whatever."]

X. That the notions which are simplest and self-evident, are
obscured by logical definitions; and that such are not to be
reckoned among the cognitions acquired by study, [but as born with
us].

I do not here explain several other terms which I have used, or
design to use in the sequel, because their meaning seems to me
sufficiently self-evident. And I frequently remarked that
philosophers erred in attempting to explain, by logical definitions,
such truths as are most simple and self-evident; for they thus only
rendered them more obscure. And when I said that the proposition,
_I_ THINK, THEREFORE _I_ AM, is of all others the first and most
certain which occurs to one philosophizing orderly, I did not
therefore deny that it was necessary to know what thought,
existence, and certitude are, and the truth that, in order to think
it is necessary to be, and the like; but, because these are the most
simple notions, and such as of themselves afford the knowledge of
nothing existing, I did not judge it proper there to enumerate them.

XI. How we can know our mind more clearly than our body.

But now that it may be discerned how the knowledge we have of the