Philocrat said:
How true is the claim that everything in the whole universe can be explained by Physics and Physics alone? How realistic is this claim? Does our ability to mathematically describe physical things in spacetime give us sufficient grounds to admit or hold this claim? Or is there more to physical reality than a mere ability to matheamtically describe things?
This question is very easy to answer, especially if when you use the term "explain" you mean prove. Of course there are people who've attempted purely physical explanations, but no one knows if their models are correct.
Right now, everything in the universe
cannot be explained by physics. Not a single informed person would say it can. In the future maybe it will be, but as of now that possibility is a long way off. The two biggest obstacles to a 100% physicalist model are life and consciousness.
You might think the two main contestants for explaining the basis of life and consciousness are physicalists and the religious, but I'd say religion isn't even in the running. In terms of providing a rational, evidence-supported model of life/consciousness it seems there is the physicalist side, and the "something more" side.
The suspicion there's something more is often the result of observing the organizational quality of life, which is atypical of physical processes; and for consciousness, it is that physical principles can't explain its subjective aspect.
One thing we know for certain is if there is something more involved in life/consciousness, it is entwined with the physical. That's why, in my opinion, I don't think any "-ism" model (you know, creation-ism, physical-ism, etc.) is going to account for everything. When you see someone, in advance of investigation, determined to prove creation is entirely physical or entirely spiritual (or whatever), it means they have to gloss over or ignore aspects that really don't fit into a single category of an -ism.
It seems the rarest thinker and investigator is one determined to find and accept the truth no matter what it may be, and who in pursuit of the truth is willing to investigate every facet of existence, again, no matter what it may be.