LogFAQs > #926392154

Quantum mechanics proves particles fundamentally non deterministic (even if we don't fully understand them), but if each particles wave function collapsing result is part of the definition of the universe, part of the input to the calculation, then.... the universe is obviously deterministic.

This is essentially false. Solve Schroedinger's equation, and not only do you get accurate results, but also get explanations of why a wave function looks like a particle at classical energy / time scales. The question isn't "is the particle deterministic" so much as "why is what we see the born rule instead of the waves themselves like in EM".

And to point out, like, wave function collapse is essentially the worst of all philosophical and physical worlds. Because that's proposing that there is a 1) non-unitary (i.e. not probability preserving) transformation that happens every single time a measurement is made, despite nothing in the equation or experiments indicating this happens (decoherence / entanglement happens on a gradual scale and have basically been confirmed up to larger and more energetic systems all the time and 2) time asymmetric, which like, is essentially the unitary point but you're also violating CPT symmetry at this point, which once again is like hyper confirmed. I dare someone who believes in wave function collapse to give a coherent account of what happens to the wave function in the delayed choice quantum eraser experiment.