Leibniz’s Arguments for the Existence of God

0. Leibniz says that if God did not exist, not only nothing else would exist, but there would be nothing possible either. This is because the notions of possibilia are found in God’s mind.  Eternal truths exist in the mind of God.

1. Each particular contingent fact in the world has an explanation.  For instance, the state of a monad at t₁ is explained by the state it had had at t₀.  And so on, ad infinitum.  We can thus give infinite explanatory chains.  But such chains fail to explain everything.  Leibniz gives the analogy of a book of geometry.  We might explain how our copy came to exist: it was copied from another copy.  And the latter was copied from yet another.  And so on ad infinitum.  But when we’ve said this, obviously we’ve left something unexplained: we’ve not explained why the book is as it is (e.g., why it contains the Pythagorean theorem) and we’ve not explained why there is a book at all.

Likewise an infinite chain of events in the history of the universe fails to answer a number of questions.  It fails to explain why there exists something rather than nothing, for instance.  It fails to explain why the something is arranged in a certain global structure (e.g., always obeying the laws of nature that it does) rather than another possible global structure.

Therefore, we must go beyond the whole series of contingent facts.  Now, each explanation must be in terms of something existing.  You can’t explain why something happened without invoking something that exists.  But it seems at first sight that if so, then you can’t get away from infinite chains.  Suppose you come up with the activity of some being X as the explanation of everything else in the universe.  You can still ask: Why does being X itself exist?  If there is to be an explanation of the whole universe’s being what it is—think of it as an explanation for the conjunction of all true propositions—this explanation must involve a being whose existence is self-explanatory.

This leads one to the notion of a necessary being, i.e., a being whose existence is logically necessary, a being which could not fail to exist, a being whose nonexistence is self-contradictory because necessary existence is a part of its very essence, part of what it is.

This being won’t be physical, because anything physical is presumably contingent.

This is a cosmological argument.

Here lies what one calls the gap problem of the cosmological argument.  The cosmological argument establishes that there was a first cause of the universe.  Since substances, monads, are the only kinds of things that have independent existence, then this being must be a substance or monad (of sorts).  But is this being God?  God is supposed to be a being with all kinds of exalted attributes.  One would want at a minimum to argue that this prime monad is a person, i.e., an intelligent being, and that there is only one of them, rather than several cooperating together, and that he is good.

Personhood isn’t that far away given that Leibniz thinks that all monads are somewhat aware.  So it can’t be a completely unconscious first cause.  But, moreover, one might argue—and Leibniz seems to talk in this way though it is not immediately clear that it makes sense on his view of free will—that the first cause of everything else has to be free.  If there is only one thing it can create, if it has no choices, then there is only one universe possible.  But that is plainly false: clearly, things could have been otherwise.  So it must be a free being.

Some people think that quantum phenomena can have some sort of indeterminism.  Leibniz, of course, disagrees.  Could these people say that some kind of random physical phenomenon was the first cause, and because it was random, it is possible for things to have gone differently?  No.  For among the things that could have gone differently, surely, are the laws of nature.  And a physical phenomenon can’t change the laws of nature: a physical phenomenon is governed by the laws of nature, constrained by the laws of nature.

Besides, one could argue for intelligence in the first cause on the basis of the organization of the world, though Leibniz seems not to do so so much.  Even now, people argue in this way.  For instance, the basic laws of nature have certain constants in them, like the constant in the law of gravitation or the mass of the electron.  If these constants had values somewhat different from those that they in fact have, stars would not have formed and there would not have been carbon atoms, and life, at least as we know it, would have been impossible.  It is improbable that they got just the right values randomly, and so the values are a sign of the intelligence of the creator.

Is this being one or many?  Leibniz thinks the unity and interrelatedness of the universe bespeaks its having been created by a single being rather than by committee. 

Besides, on Leibniz’s view, there is no intercommunication of monads, except insofar as God creates some monads.  So the different gods could not speak together, and could not cooperate together.

Leibniz goes on to add that the being eminently has all the perfections of things.  According to Descartes, there are two ways one can have some perfection, i.e., some good feature.  One can have it formally, which just means one has it the normal way.  Someone who has wisdom formally is himself wise;  a vase has beauty formally.  But one can also have it eminently, i.e., have it in one’s mind in such a way as to be able to produce it in other things.  Thus, the potter who makes a beautiful vase has the beauty of a vase eminently.  Leibniz then refers to the idea that the perfection of a thing is to be found in its cause, and argues therefore that all the perfections of things in the world—including in our souls—are also to be found in God, albeit perhaps only eminently.