The Argument

1. Whatever begins to exist has a cause of its existence.
2. The universe began to exist.
3. Therefore, the universe has a cause of its existence.

Note that the primary argument is philosophical and mathematical.  It’s not dependent on any particular cosmology; however, the leading model of cosmology and particle physics, the standard model (big bang), simply confirms the philosophy. The argument for premise 1 is that anything that begins to exist does so temporally, at some indexical moment of time.  Because there is a difference between moments, an earlier or later than, there must be a cause to the thing which begins to exist, which determines its temporal existence.  William Lane Craig offers two arguments for premise 2