>because I believe at least that an internally consistent external world exists and a global conspiracy of physicists doesn't.
The assertion that the world must be internally consistent is quintessential rationalism, not materialism or empiricism at all. Science's core value is empiricism, NOT rationalism. Empiricism and rationalism are at odds with one another and make incompatible claims.
>I'm just the same; I don't pretend to have a deep and detailed understanding of quantum physics, but I accept it as true because I believe at least that an internally consistent external world exists and a global conspiracy of physicists doesn't. If you quizzed me, at some level of detail I'd have to start guessing. My incorrect guesses shouldn't be mistaken for intentional rejection of established theories.
This is one of the weakest epistemic arguments I've ever heard. But also very honest.
You're basically saying that your central ontological conviction is that a group of humans called physicists are the ontological authorities, but you can't actually tell us what ontology it is that those authorities advocate, but whatever it is, you're sure they're right and their opponents are wrong.
This is a brutally honest admission: most fans of science have no idea what science is actually saying and couldn't survive a brief cross-examination of their "scientific" worldview. They would keep getting tripped up and go back to "I agree with what Joe says, and even though I can't explain what it is that Joe says, I am sure he is right and you are wrong, and I'm sure that Joe would have great arguments to defeat you with."
Of course, this is an illogical argument and completely fails. If you can't describe the position of the authority (PoA) that you trust in, then you can't compare the position of the authority (PoA) to the position of others (PoO).
If you don't know PoA, then you don't know that PoO is not equal to PoA. You can't, on your own, determine if PoA == PoO or if PoA != PoO. Since you can't make this comparison, you can't make any argument at all and can't make any meaningful statements about PoO. You can't even claim that someone's argument conflicts with your authority's argument, because it's impossible to know that PoA != PoO when you don't know what PoA is.
The only epistemic position you are left with is to robotically repeat the profession of the faith:
"There is no truth but physics and physicists are that truth's prophets."
Most self-proclaimed atheists are in the same boat as you, but far less aware of their ignorance of their own doctrines.
Most atheists totally fail to articulate an internally consistent scientism, and also fail to articulate a scientism that is compatible with the scientism that physicists articulate.
Again and again they fall back on "the prophet is right, but I don't know what he is right about."
Their ontology and epistemology is a "I'll believe what they're believing" kind of finger-pointing.
So now you see why philosophers like me think "New Atheists" are anti-intellectuals--and why we have criticized New Atheists of having the same religious ignorance and fervor that is common among Christians. To rationalists, Christians and New Atheists look like two authority-based religions with different prophets.