Funny how we don't even fully understand what happens when we crack our joints but are certain about how the Universe "essentially" works.
You may take it from my posing the question that I think its obvious that joint cracking is determined by physics, and I do tend to think this, but I think a compelling argument can at least be made that joint cracking might not actually be fundamentally determined by physics.
It isn't that I agree with the person who wrote Asimov the letter (in fact, based on his description, I frankly wonder if the letter writer wasn't my father). Its just that there is something subtly wrong with Asimov's view of the progress of scientific knowledge.
At least its extremely instrumentalist. If we think of knowledge as a sort of temporary mental state which lives between setting up a physical state and making a measurement, then, yes, knowledge has progressed in exactly the way that Asimov is saying. And that is nothing to sneeze at.
But like consider quantum mechanics. People still cannot make heads or tails of what the ontology of quantum mechanics is, despite some compelling stories. And that makes perfect sense since QM is not compatible with special or general relativity! So its dumb to try and make sense of what QM tells us about what is. So why not try to understand what the ontology of QFT is? This seems reasonable, since QFT is capable of making correct predictions (at least in the scattering regime) and is invariant. But no one on earth can write down a coherent mathematical theory of QFT, so interpretation is even more difficult than QM. And this is yet to even try to tackle with conceptual gap between GR and QM/QFT, where we genuinely are perplexed but at least have good reason to think that the final interpretation of QM or spacetime has to have something to do with the way that the two theories interact.
From this point of view as our ability to connect experiment with outcome has increased our ability to actually say what it is we are even talking about outside of the purely instrumental has decreased since the 19th Century. Back then we though we knew that there were atoms or electrons or whatever. Light waves or photons. Now, I would argue very strenuously, we genuinely have no understanding at all of what those things are outside of a set of purely instrumental definitions which leave a lot to be desired.
My personal understanding here is that really there are no electrons, photons, quantum fields, masses, gravity. There is just the single substance of the universe which we have learned to manipulate and predict with ever improving precision (in limited cases). Maybe that is knowledge? Doesn't always feel like it.
lionkor•30m ago