Why There Almost Certainly Is A God: Part Ia: The Leibnizian Cosmological Argument

I've been inactive for awhile and so thought I'd get back into things with a series concerning the existence of God. The title of this blog post is taken from a good book by British theologian, Keith Ward, which is itself an inversion of a phrase taken from Richard Dawkins' The God Delusion. We shall first start by perusing the various cosmological arguments in favour of God's existence, starting with the argument of Gottfried Wilhelm von Leibniz or the Leibnizian cosmological argument.

According to Leibniz, everything that exists has an explanation for its existence. For most things, that explanation is typically rooted in an external cause. Leibniz argues that there must be an ultimate explanation for why there is something (i.e. the universe) rather than nothing, which follows from his first premise. If everything has an explanation for its existence, then there is an explanation for why there is something rather than nothing.

Now, whilst most things in everyday experience have an explanation rooted in an external cause, this is not the only possible type of explanation. Something could be self-explanatory, that is to say: it could have an explanation rooted in the necessity of its own nature. In order for atheism to be true, the universe (or at the least, some part of it) would have to be metaphysically necessary in order to be self-explanatory.

Is the universe self-explanatory? Or, rather, is it metaphysically necessary in the sense meant by philosophers? The answer is no, for the universe lacks properties that is required for something to be considered metaphysically necessary. Something that is metaphysically necessary possesses all of its attributes necessarily, meaning it is the same in every possible world. For example, the universe is comprised of matter and energy, which can be organised differently and so there are different possible configurations in each possible world.

So, the universe must have an explanation rooted in an external cause. Can this chain of explanations go on infinitely? No, for there must be an ultimate explanation for why there is something rather than nothing. In order to escape an infinite chain, we must posit an ultimate explanation that is itself self-explanatory, that is to say, it is metaphysically necessary.

We are presented with the following argument:
1. Everything that exists has an explanation for its existence, rooted in the necessity of its own nature or in an external cause.
2. The universe exists.
3. The universe has an explanation for its existence.
4. The universe does not have an explanation for its existence rooted in the necessity of its own nature.
5. Therefore the universe has an explanation for its existence rooted in an external cause.