A Laddie on another thread has said that beliefs should have sound reasons so sound reasons for the following if you please...
Depends on what you mean by some of the terms, but...
Materialism
It works?
Do people have a philosophical 'belief' in materialism? I suspect that the consistent, reliable evidence of scientific enquiry that follows on from a materialist assumption is validation that it's a pragmatic way to operate, but in the main I think people accept that materialism is likely given the lack of any reliable evidence for anything else.
Physicalism
I've never heard of 'physicalism' before; looking it up it seems like a specific variation on materialism, and where it's accepted I'd guess it's accepted on the same basis.
Empiricism
Empiricism isn't a belief, it's a methodology - it's still used because it's effective. I accept there are probably some people that try to ideologize it - probably into something approaching materialism - but that's not what it is.
Scientism
Just a derogatory term form a materialist, in most of the instances I've seen it used. It's not inherently justifiable from an ideological point, for much the same reasons as materialism - science is founded on the principal that any given finding is provisional. That said, if science is the study of the causes and effects of reality (generally through an empirical method) then the only things that are outside of science are those things which are not part of reality? In principal, the only things that are outside of science's scope are those things which either are not, or have no, effects; are there any?
Naturalism
Scientific materialism - we have natural things occurring, we can detect and measure those things and draw conclusions from them that are consistent with further activity. It's already validated, practically. What takes it to naturalism is excluding the possibility of anything else; if the something else exists, it's also part of nature/reality, and then there isn't a differentiation between Naturalism and Scientism - if you want to posit that there's something that's both natural but not part of reality then that's going to take some doing... feasible, perhaps, but I'll wait to see if it's out there.
O.