In the sixth
of his Meditations
on First Philosophy, Descartes writes:
[T]here is a vast difference between
mind and body, in respect that body, from its nature, is always divisible, and
that mind is entirely indivisible. For
in truth, when I consider the mind, that is, when I consider myself in so far
only as I am a thinking thing, I can distinguish in myself no parts, but I very
clearly discern that I am somewhat absolutely one and entire; and although the
whole mind seems to be united to the whole body, yet, when a foot, an arm, or
any other part is cut off, I am conscious that nothing has been taken from my
mind; nor can the faculties of willing, perceiving, conceiving, etc., properly
be called its parts, for it is the same mind that is exercised [all entire] in
willing, in perceiving, and in conceiving, etc. But quite the opposite holds in corporeal or
extended things; for I cannot imagine any one of them [how small soever it may
be], which I cannot easily sunder in thought, and which, therefore, I do not
know to be divisible. This would be
sufficient to teach me that the mind or soul of man is entirely different from
the body, if I had not already been apprised of it on other grounds.