it
would then be limited by something else of the same kind, which
would also necessarily exist (Prop. vii.); and there would be
two substances with an identical attribute, which is absurd
(Prop. v.). It therefore exists as infinite. Q.E.D.

Note I.--As finite existence involves a partial negation, and
infinite existence is the absolute affirmation of the given
nature, it follows (solely from Prop. vii.) that every substance
is necessarily infinite.

Note II.--No doubt it will be difficult for those who think
about things loosely, and have not been accustomed to know them
by their primary causes, to comprehend the demonstration of Prop.
vii.: for such persons make no distinction between the
modifications of substances and the substances themselves, and
are ignorant of the manner in which things are produced; hence
they may attribute to substances the beginning which they observe
in natural objects. Those who are ignorant of true causes, make
complete confusion--think that trees might talk just as well as
men--that men might be formed from stones as well as from seed;
and imagine that any form might be changed into any other. So,
also, those who confuse the two natures, divine and human,
readily attribute human passions to the deity, especially so long
as they do not know how passions originate in the mind. But, if
people would consider the nature of substance, they would have no
doubt about the truth of Prop. vii. In fact, this proposition
would be a universal axiom, and accounted a truism. For, by
substance, would be understood that which is in itself, and is
conceived through itself--that is, something of which the
conception requires not the conception of anything else; whereas
modifications exist in something external to themselves, and a
conception of them is formed by means of a conception of the
thing in which they exist. Therefore, we may have true ideas of
non--existent modifications; for, although they may have no
actual existence apart from the conceiving intellect, yet their
essence is so involved in something external to themselves that
they may through it be conceived. Whereas the only truth
substances can have, external to the intellect, must consist in
their existence, because they are conceived through themselves.
Therefore, for a person to say that he has a clear and
distinct--that is, a true--idea of a substance, but that he is not
sure whether such substance exists, would be the same as