The Cosmological Argument

The cosmological argument is the oldest and most widely discussed argument for the existence of God in the philosophical tradition, going back through Aquinas, through the medieval Islamic philosopher al-Ghazali, through the Neo-Platonists, to Aristotle's Unmoved Mover. Its modern form — sharpened by twentieth-century cosmology — is called the Kalam cosmological argument (from the Arabic kalam, the medieval Islamic tradition of theological reasoning). It is deceptively simple: the universe began to exist; whatever begins to exist has a cause; therefore the universe has a cause. The interesting question is what properties that cause must have — and the answer is remarkably close to what the first verse of the Bible already said.

Premise one: the universe began

Until the early twentieth century, the dominant assumption in science and philosophy was that the universe was eternal — that it had always existed, with no beginning. If the universe had no beginning, the cosmological argument had a ready answer: it had no cause because it never started.

That assumption has been overturned by two independent lines of evidence.

The Big Bang. In the 1920s, Edwin Hubble's observations established that the universe is expanding — galaxies are moving apart from each other in all directions. If you run the expansion backward, all the matter and energy in the universe converge to a single point of infinite density at a finite time in the past. This initial singularity — the Big Bang — is where space, time, matter, and energy came into existence. The universe is not infinitely old. It had a beginning roughly 13.8 billion years ago, by the mainstream estimate.

The Borde-Guth-Vilenkin theorem (2003). Alexander Vilenkin, Arvind Borde, and Alan Guth — three secular cosmologists — proved that any universe which has been expanding on average throughout its history must have had a beginning. This theorem applies even to multiverse proposals: the multiverse itself, if it has been expanding, also had a beginning. Vilenkin wrote: "It is said that an argument is what convinces reasonable men and a proof is what it takes to convince even an unreasonable man. With the proof now in place, cosmologists can no longer hide behind the possibility of a past-eternal universe. There is no escape: they have to face the problem of a cosmic beginning." The past is not infinite.

Premise two: whatever begins has a cause

This premise is the most intuitive of the two. Nothing in human experience comes into existence without a cause. A chair comes from a carpenter and wood. A thought comes from a brain. A physical effect comes from a physical cause. The principle of causality — that things that begin to exist require something to bring them into existence — is one of the bedrock assumptions of all scientific inquiry. To deny it for the universe while applying it everywhere else requires a special justification that has not been provided.

The standard objection is quantum mechanics: at the subatomic level, particles appear to pop in and out of existence randomly, without apparent causes. But this objection confuses "we cannot identify the cause" with "there is no cause" — a gap in our knowledge, not evidence of uncaused events. And even quantum fluctuations occur in pre-existing quantum fields governed by pre-existing laws. They do not represent creation from nothing; they represent rearrangement within something already there. The universe itself — space, time, matter, energy, and the laws that govern them — is the something that needs explanation.

The conclusion: what the cause must be like

If the universe began to exist and has a cause, what can we say about that cause?

The cause must be outside the universe: it cannot be part of the physical system it brought into existence, any more than a painter is part of the painting. It precedes space, time, matter, and energy; it is not subject to them.

The cause must be uncaused itself, or there is an infinite regress of causes (which philosophers like Aquinas argued is itself incoherent). To avoid the regress, there must be something that exists necessarily — something that has always existed and could not fail to exist.

The cause must be enormously powerful: it brought all the matter, energy, space, and time in the observable universe into existence from nothing.

Most strikingly: because time itself began with the universe, the cause must be timeless — or at least have existed without time before time began. And because space began with the universe, the cause must be non-spatial: not a physical thing in any place.

A timeless, non-spatial, enormously powerful, uncaused cause that freely chose to create a universe. The first verse of Genesis already described this: "In the beginning God created the heaven and the earth" (Genesis 1:1). The word "beginning" implies that time itself started. The creation is external to the Creator. The argument does not get to the God of Abraham and Isaac in one step — it gets to something very much like Him, and then Scripture provides the identification.

Standard objections, addressed honestly

"Who made God?" This misunderstands the argument. The argument does not claim that everything has a cause; it claims that everything that begins to exist has a cause. God, on the theistic account, did not begin to exist — He exists necessarily, without beginning. The question "who made God?" applies the cause requirement to something the argument explicitly exempts. It would be like asking what is north of the North Pole: it misapplies the concept.

"The universe came from nothing." Some physicists (notably Stephen Hawking and Lawrence Krauss) have argued that the universe could have arisen from "nothing" via quantum processes. But physicists using the word "nothing" in this way typically mean quantum vacuum states, mathematical structures, or the laws of physics — all of which are something, not nothing. Nothing, properly defined, has no properties and no potential. It is not a pregnant void; it is the absence of everything. True nothing cannot fluctuate, because fluctuating is a property, and nothing has no properties. The universe did not come from nothing; it came from something — and the question of what that something is remains.

"The multiverse explains it." Multiverse proposals attempt to explain the apparent design of the universe's constants by positing that many universes exist with different constants, and ours happens to be life-permitting. But the multiverse does not remove the need for a cause; as the BGV theorem shows, a multiverse that has been expanding also had a beginning. And generating a multiverse requires a mechanism, which is itself something that needs explaining. The multiverse multiplies the entities to be explained, not the explanations.

Where this lands

The cosmological argument is not a proof of the God of Scripture in a single syllogism. It is a proof that the universe had a beginning, and that its beginning requires a cause with specific properties: timeless, non-spatial, uncaused, immensely powerful, and personal (since a personal choice to create is more explanatory than an impersonal mechanism that always produces effects, given that there was once no universe). Those properties match what theism has always claimed about God.

For the Christian, the argument is a confirmation of what is already known by faith and revelation. It shows that the opening claim of Scripture — "In the beginning God created" — is not at odds with physics. It is what physics points to when followed far enough. The secular scientist Vilenkin, standing at the edge of the universe's beginning, said that cosmologists can no longer hide behind the possibility of a past-eternal universe. Genesis 1:1 was never hiding. It said this from the start.

Related: The Fine-Tuning of the Universe, The Moral Argument, Not Meant to Be Blind, Providence. Primary sources: William Lane Craig, The Kalam Cosmological Argument (Macmillan, 1979); Borde, Guth, Vilenkin, "Inflationary spacetimes are not past-complete," Physical Review Letters 90, 151301 (2003) (public academic paper); Alexander Vilenkin, Many Worlds in One (Hill and Wang, 2006). Hawking and Krauss counter-arguments from their published works.