Given what has already been said about the origin of the universe, materialism should be rejected.
Still, this doesn’t get us to theism. For that to be the case, the cause must be shown to be personal.
This is the key point of the Kalam Cosmological Argument, and the area where I had the most questions. Generally, it is said that minds are the only non-physical objects that could be said to cause anything. The only other alternative would be abstract objects (such as numbers), which aren’t causal entities.
To me, the obvious question is “how do we know there isn’t a third alternative?”. In first hearing the argument, I was unable to think of anything else, but this hardly seemed a good reason to accept that there could be no such thing.
I really didn’t take the Kalam very seriously, then, until I started to notice that it wasn’t just me who had trouble thinking of a third alternative. So far as my reading has revealed, no one has proposed anything else. So, this wasn’t simply a matter of my own personal inability to solve a puzzle, but there really being no other concievable option for consideration.
Still, one might suggest that something beyond our imagining could have caused the universe.
This seemed a reasonable enough idea, until I tried to apply it to other areas of life. We never know for certain about things in life, so we go with the most reasonable option on the table. To claim that the “there might be something else no one has thought of” objection is valid is to reject all knowledge.
In thinking this over, I was willing to tentatively conclude that the mind is the best model we have for describing the first cause of physical reality.
This wasn’t absolutely conclusive, of course. But it was enough that I decided to think on it further. I’ll get to those thoughts in the future.