"Nonphysical" follows, in the sense of "not the stuff discussed in our current scientific paradigm", but that does not logically entail it is mental stuff.
Nonphysical means that it cannot be studied by science. Science is limited to the physical realm. This subject has to do with philosophy, not science. And yes, if it can be shown that the cause of the universe is not a personal agent, then we should believe it.
Physics has already given up on trying to successfully describe the world in terms of things amenable to common sense. They speak of "curved space time" and other bizarre concepts. Although the KCA shows it is not something currently in the resources of physics, there is no reason to think future developments or a new paradigm wouldn't allow scientists to figure it out.
Yeah, but the problem with those is that you have to make new laws of physics and even change the current ones. It is actually amusing how Stephen Hawking compared some of these models to science fiction. Another problem is that they have only one criteria: the cause must be physical. To me, it seems that they aren't trying to discover the reality but to explain away things that aren't supporting naturalism.
This is like the ancient physicists. They'd compare the competing "explanatory virtues" of positing the various elements as the fundamental nature of the universe: and indeed, that's all they had the conceptual tools to deal with. They had no idea about the widened conceptual tools that allow us to think about that question today. Maybe fire was the only explanation of the fundamental dynamic yet static appearing universe, as Heraclitus felt, but it was totally incorrect.
They were wrong. Because they couldn't discover new things with good instruments, they had to explain away things they didn't understand (like some people are now doing). And they weren't even scientists, they had a certain school of thought and there were many other ways to describe our reality.
The history of science is filled with examples like this. Proponents of old paradigms make theoretical posits, without independent explanatory motivation (without empirical predictions, for example), and fail to see the real solution because they don't have the right concepts yet.
I'm suggesting that theists are making the same mistakes these ancient scientists made.
I don't see the conclusion. ALL the scientific discoveries we have found haven't been disproven. Yeah, some things like the theory of evolution have changed because we have found new evidence to lead the way.
So just because the theists are open to material AND immaterial explanations, the theists are wrong? In my opinion, the naturalist is not open to the evidence because he only allows natural explanations.