All questions › Arguments for God
The Kalam cosmological argument
Short answer
The Kalam cosmological argument was developed by medieval Islamic philosophers and has been popularized by William Lane Craig. It is simple:
1. Whatever begins to exist has a cause. 2. The universe began to exist. 3. Therefore, the universe has a cause.
Premise 1 is a basic intuition we rely on everywhere: things don't pop into being from absolutely nothing. Premise 2 has philosophical support, because an actually infinite series of past events seems impossible. It also has scientific support from Big Bang cosmology and the Borde–Guth–Vilenkin theorem, which suggests that any universe that is expanding on average must have a past boundary.
If the universe has a cause, that cause must lie beyond space, time and matter. So it must be timeless, spaceless, immaterial and enormously powerful. Craig argues it must also be personal, because only a free agent can explain how a timeless cause produces an effect that begins in time. That description closely matches what theists mean by "God." The argument doesn't prove everything Christians believe, but it makes the case that atheism has a beginning-of-the-universe problem.
Objections and responses
ObjectionQuantum events happen without causes.
ResponseQuantum events take place inside a quantum vacuum governed by physical laws. That is not 'nothing.' Many interpretations of quantum mechanics are also fully deterministic.
Read more →ObjectionMaybe the universe is eternal, through a multiverse or cycles.
ResponseMost proposed models still need a beginning, according to the BGV theorem and the thermodynamics of cyclic models.
Read more →ObjectionThen what caused God?
ResponsePremise 1 applies to things that begin to exist. A timeless first cause didn't begin.
Read more →ObjectionWhy think the cause is personal?
ResponseA timeless, unchanging set of conditions would produce an eternal effect. A temporal effect from a timeless cause fits best with a free agent who chooses to create.
Read more →Best resources
- The Kalam Cosmological Argument by William Lane Craig (book)
Read The Kalam Cosmological Argument by William Lane Craig for the scholarly monograph that revived the argument; technical and detailed, for advanced readers. See especially the parts on the cosmological argument.
- Reasonable Faith by William Lane Craig (book)
Read Reasonable Faith by William Lane Craig for an in-depth, scholarly approach that is technical yet approachable, best for readers ready for careful philosophical argument. See especially the parts on the cosmological argument.
- The Blackwell Companion to Natural Theology by William Lane Craig & J.P. Moreland (eds.) (book)
Read The Blackwell Companion to Natural Theology by William Lane Craig & J.P. Moreland (eds.) for an advanced academic reference with long essays by specialists on each argument for God. See especially the parts on the cosmological argument.
- God and Cosmology (debate, 2014) by William Lane Craig vs. Sean Carroll (talk)
Watch God and Cosmology (debate, 2014) by William Lane Craig vs. Sean Carroll for a lively, high-level debate between a philosopher and a physicist; great for hearing both sides at full strength.
Book links are Amazon affiliate links. As an Amazon Associate, Big Question Index earns from qualifying purchases.