Leibniz’s solution is this:  what are mere possibilities of thought for us are possibilities of action for God.  For a human subject, possibilities of action are limited to what arises out of his actual situation, but possibilities for thought are not so limited.  I can conceive a world different in many respects from this world, in which, for example, vegetables should be gifted with thought and speech; but I can do nothing towards bringing it about.  My imaginary world is practically impossible but speculatively possible, in the sense that it contradicts no single principle of necessary and immutable reason.  I, indeed, can explore only a very little way into the region of sheer speculative possibility; God does not explore it, he simply possesses it all:  the whole region of the possible is but a part of the content of his infinite mind.  So among all possible creatures he chooses the best and creates it.

But the whole realm of the possible is an actual infinity of ideas.  Out of the consideration of an infinity of ideas, how can God arrive at a choice?  Why not?  His mind is not, of course, discursive; he does not successively turn over the leaves of an infinite book of sample worlds, for then he would never come to the end of it.  Embracing infinite possibility in [32] the single act of his mind, he settles his will with intuitive immediacy upon the best.  The inferior, the monstrous, the absurd is not a wilderness through which he painfully threads his way, it is that from which he immediately turns; his wisdom is his elimination of it.

But in so applying the scheme of choice to God’s act, have we not invalidated its application to our own?  For if God has chosen the whole form and fabric of the world, he has chosen everything in it, including the choices we shall make.  And if our choices have already been chosen for us by God, it would seem to follow that they are not real open choices on our part at all, but are pre-determined.  And if they are pre-determined, it would seem that they are not really even choices, for a determined choice is not a choice.  But if we do not ourselves exercise real choice in any degree, then we have no clue to what any choice would be:  and if so, we have no power of conceiving divine choice, either; and so the whole argument cuts its own throat.

There are two possible lines of escape from this predicament.  One is to define human choice in such a sense that it allows of pre-determination without ceasing to be choice; and this is Leibniz’s method, and it can be studied at length in the Theodicy.  He certainly makes the very best he can of it, and it hardly seems that any of those contemporaries whose views he criticizes was in a position to answer him.  The alternative method is to make the most of the negative element involved in all theology.  After all, we do not positively or adequately understand the nature of infinite creative will.  Perhaps it is precisely the transcendent glory of divine freedom to be able to work infallibly through free instruments.  But so mystical a paradox is not the sort of thing we can expect to appeal to a late-seventeenth-century philosopher.