The Ethics | Page 5

i.),-it follows that setting the modifications aside,
and considering substance in itself, that is truly, (Deff. iii. and vi.),
there cannot be conceived one substance different from another,-that is
(by Prop. iv.), there cannot be granted several substances, but one
substance only. Q.E.D.
PROP. VI. One substance cannot be produced by another substance.
Proof.-It is impossible that there should be in the universe two
substances with an identical attribute, i.e. which have anything
common to them both (Prop. ii.), and, therefore (Prop. iii.), one cannot
be the cause of the other, neither can one be produced by the other.
Q.E.D. Corollary.-Hence it follows that a substance cannot be produced
by anything external to itself. For in the universe nothing is granted,
save substances and their modifications (as appears from Ax. i. and
Deff. iii. and v.). Now (by the last Prop.) substance cannot be produced
by another substance, therefore it cannot be produced by anything
external to itself. Q.E.D. This is shown still more readily by the
absurdity of the contradictory. For, if substance be produced by an
external cause, the knowledge of it would depend on the knowledge of
its cause (Ax. iv.), and (by Def. iii.) it would itself not be substance.
PROP. VII. Existence belongs to the nature of substances.
Proof.-Substance cannot be produced by anything external (Corollary,
Prop vi.), it must, therefore, be its own cause-that is, its essence

necessarily involves existence, or existence belongs to its nature.
PROP. VIII. Every substance is necessarily infinite. Proof.-There can
only be one substance with an identical attribute, and existence follows
from its nature (Prop. vii.) ; its nature, therefore, involves existence,
either as finite or infinite. It does not exist as finite, for (by Def. ii.) 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 if he said that he had a true idea, but was not sure
whether or no it was false (a little consideration will make this plain) ;
or if anyone affirmed that substance is created, it would be the same as
saying that a false idea was true-in short, the height of absurdity. It
must, then, necessarily be admitted that the existence of substance as its
essence is an eternal truth. And we can hence conclude by another
process of reasoning-that there is but one such substance. I think that
this may profitably be done at once ; and, in order to proceed regularly
with the