What Is the Cosmological Argument?
The cosmological argument is a family of philosophical arguments that reason from the existence of the universe (the "cosmos") to the existence of a cause or explanation for it — typically identified as God. It is one of the oldest and most widely discussed arguments in the philosophy of religion, with roots stretching back to Aristotle, developed by Islamic philosophers like Al-Ghazali, and refined by Thomas Aquinas in his famous Five Ways.
The Kalam Cosmological Argument
The most discussed contemporary version is the Kalam Cosmological Argument, popularised by philosopher and theologian William Lane Craig. It runs as follows:
- Everything that begins to exist has a cause.
- The universe began to exist.
- Therefore, the universe has a cause.
The argument then explores what kind of cause could produce the universe. Since the cause must exist outside space, time, and matter (because it brought those things into being), it must be spaceless, timeless, immaterial, enormously powerful, and — Craig argues — personal (able to freely choose to create).
Support for Premise 2: The Universe Began to Exist
This is often the most contested premise. Two lines of support are commonly offered:
Scientific Evidence
The Big Bang model, now the standard cosmological model, indicates that the universe had a beginning roughly 13.8 billion years ago. Space, time, matter, and energy all came into existence at that point. The Borde-Guth-Vilenkin theorem (2003) further demonstrates that any universe that has been expanding on average must have a past boundary — a beginning.
Philosophical Arguments
An actual infinite cannot exist in reality, only in mathematics. If the universe were infinitely old, an infinite number of past events would have had to occur to reach the present — which is philosophically problematic. This supports the conclusion that the past must be finite: the universe had a beginning.
Common Objections and Responses
"What caused God?"
The argument specifically applies to things that begin to exist. If God is eternal and uncaused — a necessary being who exists by his own nature — the question does not apply. The argument does not claim everything has a cause; it claims everything that begins has a cause.
"Maybe the universe caused itself"
For something to cause itself, it would have to exist before it existed — a logical impossibility. Some quantum models suggest particles appear from a "quantum vacuum," but the vacuum is not nothing; it is a physical field with properties, itself requiring explanation.
"Maybe the universe always existed"
As noted above, both scientific data and philosophical reasoning support a finite past. While some speculative models propose eternal oscillating universes or multiverses, these remain unverified and still face the Borde-Guth-Vilenkin problem.
What the Argument Does and Does Not Prove
It is important to be precise about the argument's scope. The cosmological argument, if successful, demonstrates:
- A transcendent cause of the universe exists.
- That cause is enormously powerful and immaterial.
- That cause is likely personal (can freely initiate action).
It does not, by itself, prove the God of the Bible specifically. That requires additional arguments and the witness of Scripture and history. But it clears important philosophical ground — establishing that atheistic materialism is not the default rational position it is often assumed to be.
Conclusion
The cosmological argument remains a compelling and rigorous philosophical case for theism. While no single argument settles the question of God's existence for every person, the cosmological argument invites serious intellectual engagement. For the Christian, it is one piece of a cumulative case that the universe is not self-explanatory — that behind all things is a Mind and a Maker.