We're really attached to classical physics because we're macroscopic objects. Any observation we make will inherently be an aggregate that cannot support the delicate equilibria that characterize quantum superpositions.
We actually do have a pretty good understanding of how that works. The implications of it are hard to stomach, but the mathematics of it is well understood and experimentally confirmed to a dozen decimal places. Where it contradicts our classical intuition, it is always quantum physics that wins out.
What does that mean?
Interpretations of quantum mechanics try to shove that inaccessible part of the wave function into a place where we can feel comfortable about it. But they are all a serious blow to what we think of as reality.
This is the sort of statement I expect from philosophers and not scientists.
That may be your expectation, but it's not mine. I believe (with a high degree of confidence) that the best we ever have is a Bayesian confidence in any hypothesis.
> The idea of an untestable truth is upsetting.
I think there's a big leap between "We can't test it" and "It's untestable".
I am not confident that humans 1000 years from now will still be bound by quantum indeterminacy. What we now model as probability fields may be in fact the result of a deterministic process which we do not yet understand.
May I ask why? If it is true, why do you need to test it? Is your problem unknowable truths? Or something else?
You need an additional assumption that collapse actually occurs to get rid of the world being in a massive superposition we can't observe, if you don't want Many Worlds Interpretation.
Also, physical reality is made up of quantum systems, so there is a real question as to whether the classical is actually quantum. MWI and some other realist interpretations like Bohmian Mechanics would say yes. The Copenhagen Interpretation would say the math is just a predictive tool and we don't know what's actually going on when not making measurements.