Religion is a Delusion/Mental Illness

[snookerman]

everything I've heard about the physical world leads me to think of the motion of particles as deterministic or random... are there some other qualities?

-everything you've heard- is alot of additional stuff, though, eh?  "This is made of stuff" - that's all a physical world entails.  "This is made of stuff and here are the rules as we've observed them" - is what you require.  Determinism isn't gauranteed by simple virtue of "stuff" existing, you see?  So no, there is no "must" in either the physical or the physical +.  

so yes, I think a purely physical universe must be deterministic or random... I agree that a "physical+" universe may be deterministic or random...

so the difference I see is "must be" or "may be"

You think that a purely physical universe which follows those rules you referenced, which behaves in the manner observed, that "everything you've heard" -must be deterministic or random.  It might not be prudent to saddle a claim or statement with assumptions which it cannot, -by itself- support, eh?  The two propositions (physical/physical +) do not, themselves, contain enough ass end to take us to a declaration of "must" regarding determinism, random, or "else".

(I don't disagree with you at all, btw, that might be important to keep in mind.  I also think that our purely physical universe behaves in a deterministic manner.  Ironically even this is not enough to conclude, with any certainty, that we behave in a purely deterministic manner.  What is true of the whole may not be true of the part...though I am equally uninterested in making special exemptions in our case unless we can put forward some really good observations.  All of this is additonal, nothing to do with responding to the above, just going down the rabbit hole.  I'm not entirely certain how you could tease a "must" out of anything you've ever heard...tbh.)

"You think that a purely physical universe which follows those rules you referenced, which behaves in the manner observed..."

yes, the manner observed... do you view the universe as behaving differently than observed?