God, in so far as He has
formed our mind, but would be in Him in so far as He has formed the mind
of another thing; that is to say, the ideas of the modifications of the
body would not be in our mind. But we have ideas of the modifications of
a body; therefore the object of the idea constituting the human mind is
a body, and that, too, actually existing. Again, if there were also any
other object of the mind besides a body, since nothing exists from which
some effect does not follow, the idea of some effort produced by this
object would necessarily exist in our mind. But there is no such idea.
Therefore the object of the idea constituting the human mind is a body,
or a certain mode of extension actually existing, and nothing else.

Hence it follows that man is composed of mind and body, and that the
human body exists as we perceive it.

Hence we see not only that the human mind is united to the body, but
also what is to be understood by the union of the mind and body. But no
one can understand it adequately or distinctly without knowing
adequately beforehand the nature of our body; for those things which we
have proved hitherto are altogether general, nor do they refer more to
man than to other individuals, all of which are animate, although in
different degrees. For of everything there necessarily exists in God an
idea of which He is the cause, in the same way as the idea of the human
body exists in Him; and therefore everything that we have said of the
idea of the human body is necessarily true of the idea of any other
thing. We cannot, however, deny that ideas, like objects themselves,
differ from one another, and that one is more excellent and contains
more reality than another, just as the object of one idea is more
excellent and contains more reality than another. Therefore, in order to
determine the differences between the human mind and other things and
its superiority over them, we must first know, as we have said, the
nature of its object, that is to say, the nature of the human body. I am
not able to explain it here, nor is such an explanation necessary for
what I wish to demonstrate.

This much, nevertheless, I will say generally, that in proportion as one
body is better adapted than another to do or suffer many things, in the
same proportion will the mind at the same time be better adapted to
perceive many things, and the more the actions of a body depend upon
itself alone, and the less other bodies cooe