been different, God's nature would also have been able to be
different from what it now is ; and therefore (by Prop. xi.) that
different nature also would have perforce existed, and
consequently there would have been able to be two or more Gods.
This (by Prop. xiv., Coroll. i.) is absurd. Therefore things
could not have been brought into being by God in any other
manner, &c. Q.E.D.
Note I.-As I have thus shown, more clearly than the sun at
noonday, that there is nothing to justify us in calling things
contingent, I wish to explain briefly what meaning we shall
attach to the word contingent ; but I will first explain the
words necessary and impossible.
A thing is called necessary either in respect to its essence
or in respect to its cause ; for the existence of a thing
necessarily follows, either from its essence and definition, or
from a given efficient cause. For similar reasons a thing is
said to be impossible ; namely, inasmuch as its essence or
definition involves a contradiction, or because no external cause
is granted, which is conditioned to produce such an effect ; but
a thing can in no respect be called contingent, save in relation
to the imperfection of our knowledge.
A thing of which we do not know whether the essence does or
does not involve a contradiction, or of which, knowing that it
does not involve a contradiction, we are still in doubt
concerning the existence, because the order of causes escapes
us,-such a thing, I say, cannot appear to us either necessary or
impossible. Wherefore we call it contingent or possible.
Note II.-It clearly follows from what we have said, that
things have been brought into being by God in the highest
perfection, inasmuch as they have necessarily followed from a