Why is there something rather than nothing?

The cosmological argument is the attempt to get from that question to God, and it is the most widely defended argument for God's existence in the Western tradition. It is also the one most often attacked in a form nobody defends.

Clear two things up first

The first cause is first in the order of explanation — what the rest depends on for existing at all, right now, not what happened before the rest.

This is why so who made God? misses. The argument does not claim everything has a cause. It claims that everything contingent has a cause, and then argues that the series cannot consist only of contingent things. A necessary being is not an unexplained exception to the rule; it is what the rule was pointing at.

It does not need the universe to have a beginning. Aquinas thought the universe probably began, said so, and then explicitly held that his argument works whether or not it did — an eternal chain of dependent things is exactly as much in need of explanation as a finite one. The Kalam version is the one exception that does turn on a beginning, and it is the version most often mistaken for the whole family.

The clearest version

Avicenna's proof from contingency, written around 1020, is the sharpest form and the one most of the others are variations on.

Everything that exists either exists necessarily — its nature is such that it could not fail to be — or contingently, which means something outside it accounts for its being there rather than not. Look at anything in the world and it is contingent. It came to be, it will stop, and the explanation of it lies elsewhere.

Now take the whole collection of contingent things. Each member is explained by another member. But the collection itself is still a collection of things that need not have existed, and pointing at more of its members does not explain why there is any of it at all.

So either the explanation terminates in something whose existence is not contingent, or there is no explanation. Avicenna's Necessary Existent is the first branch.

Aquinas's third way is this argument. His first two — from motion and from efficient causation — have the same shape with different starting material.

The variations

Aristotle's unmoved mover. The oldest version, from Metaphysics Lambda, and metaphysically the strangest. Motion is eternal; every moving thing is moved by something; the chain requires a first term that moves without being moved.

What is remarkable is how it moves things. Not by pushing. The unmoved mover moves the cosmos the way a beloved moves a lover — as an object of desire and contemplation, drawing rather than shoving. It is pure actuality, and what it does eternally is contemplate itself.

Note that this is not the God of Abraham. Aristotle's cosmos is uncreated and his mover has no providence, no involvement, and no interest in anything below it. The medieval reception had to do substantial work to fuse the two.

Leibniz and sufficient reason. Every fact has a sufficient reason for being so rather than otherwise. The existence of the world is a fact. Its reason cannot lie inside it. Therefore it lies outside it, in something necessary.

This version has the virtue of stating the premise the others lean on silently, which is also its exposure: the whole thing is now only as strong as the principle of sufficient reason, and whether that principle holds without exception is a live argument.

Kalam. Developed by al-Ghazālī, revived by William Lane Craig: whatever begins to exist has a cause; the universe began to exist; therefore it has a cause. The one version that genuinely needs a beginning, which is why it leans on Big Bang cosmology — and why the dispute about it is partly a dispute about whether physics supports a metaphysical premise.

Hume's objections

Hume's Dialogues put the standing critique in Philo's mouth, and it has four parts worth separating.

Causal reasoning is learned from cases inside the universe, and extending it to the universe as a whole may be illegitimate. The impossibility of infinite regress is asserted more often than it is shown. If every member of a series is explained, it may be that nothing further is required of the series. And even if the argument works, it delivers a cause — not a good one, a unique one, or a personal one.

That last objection is the one that outlived the rest.

The gap

Suppose the argument succeeds completely. What you have is a necessary being on which everything contingent depends.

You do not yet have anything that knows you exist. Getting from a necessary being to something one, simple, eternal, good, and personal takes a great deal of further argument, and every step is separately contestable. Aquinas knew this — the Five Ways end with this everyone calls God, and then he spends the rest of the Summa earning it.

The honest statement of what the argument can do is therefore narrower than its reputation. At its strongest it shows that contingent things cannot be the whole story. What the rest of the story is remains open.

Why it is worth your time

Because the question genuinely does not go away, and the argument is a serious attempt at it rather than a trick.

It is also a good test of whether you are arguing with a position or with a caricature. If your objection is who made God, or science showed the universe came from the Big Bang, you are answering the Kalam version at best and a strawman at worst. Finding the strongest form of an argument before attacking it is a discipline, and this is one of the places it is most often skipped.

Further reading