Is God the cause of the Universe (or physical reality)?
Clarifying the question
Assuming that physical reality began to exist, and it has a cause, the following question can arise in canonical Kalam Cosmological Argument: Is that cause God?
• God = def. The “greatest possible being”—maximally worthy of worship. In virtue of God's unsurpassable greatness then, God is thought to have the maximal consistent set of knowledge, power, and benevolence.
• Physical reality = def. The Universe, or conjunction of all universes, and the laws that govern them. All space and time.
It can exist with no space, time, matter
If space, time, and matter began to exist, then the cause of those three things obviously can't depend on those three things. (That would require self-causation.) So the cause is spaceless, timeless, and immaterial. This is relevant because it sounds very suspiciously like God; and functions as a powerfully fulfilled theistic prediction that atheists never imagined and entirely failed to make.
It has the power and disposition to cause it
Whatever caused the Universe to exist (i.e. space, time, matter), must have at least both the ability and disposition to cause those specific three things to exist. This is relevant because such a cause sounds very suspiciously like God; and functions as a powerfully fulfilled theistic prediction that atheists never imagined and entirely failed to make.
God wouldn't have reason to (not expected)
Even if God existed, creating a universe is not the kind of thing God would do. This is relevant because in the absence of seeing a reason to create something as highly specific as a universe, the likelihood that an all-good God would choose to create it is very low.
But no, plausibly...
• ...God sees a “choice arena” for embodied agents as very good.
The Universe never began to exist
Physical reality (all of space, time, and matter) was never caused to exist.
• ...a beginningless universe model is true
By way of response, however...
• ...space and time expanded from a nothing-point singularity
• ...general relativity's Big Bang from nothing model is true
• ...past-eternal expansions require impossible speeds
• ...total entropic decay hasn't arrived yet
• ...total generalized entropy has not maxed out yet
• ...logically, the past must be finite
God does not exist
Theism is false. There is no God to create the universe.
“God did-it” isn't an explanation
True explanations do not feature “God”.
• …“God did-it” is just an appeal to ignorance-gaps
• …“God did-it” is just an appeal to magic
• …explanations don't compound the mystery
• …explanations don't explain “too much”
• …meaningful claims are verifiable (by senses)
• …meaningful claims are falsifiable/testable
• …explanations cite effective mechanisms
• …explanations are unificationist
By way of response, however…
• …convincing theistic explanations can be imagined
• …theism can be rational
• …theism does best explain some facts