... The proposition in question is of great importance, and deserves to be well established, for it
follows that every soul is as a world apart, independent of everything else except God; that it is
not only immortal and so to speak impassible, but that it keeps in its substance traces of all that
happens to it."
He goes on to explain that substances do not act on each other, but agree through all mirroring the
universe, each from its own point of view. There can be no interaction, because all that happens to
each substance is part of its own notion, and eternally determined if that substance exists.
This system is evidently just as deterministic as that of Spinoza. Arnauld expresses his horror of
the statement (which Leibniz had made): "That the individual notion of each person involves once
for all everything that will ever happen to him." Such a view is evidently incompatible with the
Christian doctrine of sin and free will. Finding it ill received by Arnauld, Leibniz carefully
refrained from. making it public.
For human beings, it is true, there is a difference between truths known by logic and truths known
by experience. This difference arises in two ways. In the first place, although everything that
happens to Adam follows from his notion, if he exists, we can only ascertain his existence by
experience. In the second place, the notion of any individual substance is infinitely complex, and
the analysis required to deduce his predicates is only possible for God. These differences,
however, are only due to our ignorance and intellectual limitation; for God, they do not exist. God
apprehends the notion of Adam in all its infinite complexity, and can therefore see all true
propositions about Adam as analytic. God can also ascertain a priori whether Adam exists. For
God knows his own goodness, from which it follows that he will create the best possible world;
and he also knows whether or not Adam forms part of this world. There is there, fore no real
escape from determinism through our ignorance.
There is, however, a further point, which is very curious. At most times, Leibniz represents the
Creation as a free act of God, requiring the exercise of His will. According to this doctrine, the
determination of what actually exists is not effected by observation, but must proceed by way of
God's goodness. Apart from God's goodness, which