Craig loves this argument. Its proper title is the Kalam Cosmological Argument and it is formally phrased thus:
- Everything that has a beginning of its existence has a cause of its existence.
- The universe has a beginning of its existence.
- The universe has a cause of its existence.
- Craig and apologists like him then add two more steps.
- If the universe has a cause of its existence then that cause is God.
- God exists.
The first three steps of the argument have a number of flaws when examined for logical inconsistencies.
Firstly, the argument hinges on a sloppy generalization that "Everything that begins to exist has a cause" This is an unsupported assertion. It has been demonstrated in laboratory conditions that some events (on the quantum scale) do not have a cause or if they do, we have no understanding of them and to call them God would be fallacious. One must question whether it is appropriate or even possible to apply our every-day, inductively derived understanding of causality to extreme conditions such as the beginning of the universe. The philosopher Hume argued that the only way to know if a principle holds in conditions very different from those in which it was derived is to have direct experience of it happening.
Secondly, the original formulation of the argument simply proves the universe had an extant cause. Craig and his ilk add additional steps with no logical basis to get to their god of choice. You can go on YouTube and see Hamza Andreas Tzortzis, a well known Islamic apologist, use the same argument to prove his god is the creator of the universe. Whilst this doesn't refute the argument itself it does cast some doubt on William Lane Craigs use of it especially given that Craig himself admits that he doesn't believe in God because of this argument but because of personal experience and the revelation of scripture.
Thirdly, A close examination of of the premises reveals a number of logical fallacies:
Special Pleading: The argument attempts to avoid the question of gods origins with the words "Everything That Begins To Exist" without justifying why god should be exempt from the laws of causality that are then invoked to argue that everything else that exists must have been created by god.
Equivocation Fallacy: The KCA posits that the universe was created Ex Nihilo (out of nothing). This is not how everything we see around us came into being. The world around us is created Ex Materia (out of matter) in a logical chain of events involving a causal agent, some acted upon 'stuff' and a resulting event. In other words, every example we have of creation (except the afore-mentioned quantum events) is one of matter being reconfigured into different matter, not popping into existence fully formed. The universe is the only example of something truly "beginning to exist" from a previous state of nothingness, leaving no inductive support for the premise that "whatever begins to exist (Ex Nihilo) has a cause".
Taking account of this the argument should be reformulated thus:
- Everything that begins to exist Ex Materia has a cause.
- The universe began to exist Ex Nihilo
- Therefore the universe has a cause.
The argument is obviously invalid and can be discarded
Composition Fallacy Taken from Dan Barkers article 'Cosmological Kalamity'
The first premise refers to every "thing," and the second premise treats the "universe as if it were a member of the set of "things." But since a set should not be considered a member of itself, the cosmological argument is comparing apples and oranges.
We describe the the way physical objects behave within the universe by relying on induction and the laws of physics, neither of which can apply in the absence of a universe. It is a fallacy of composition to assert that the individual elements of a thing possess the attributes of a thing. A computer is good at calculations. this does not mean that every component of a computer is good at calculations. Your power supply cannot add up your bank balance.
Finally, even if we accept all its premises, the KCA does not allow for the possibility of another cause for the universe such as a natural process or a non-divine intelligence.
Given all this one must conclude that the KCA is not a sound or valid argument for the existence of god.
For another deconstruction of WLCs use of Kalam I recommend the YouTube channel Theoretical Bullshit. TBS has an entire playlist devoted to Craig and has managed to reformulate Kalam to disprove the existence of God.