[VadeRetro]

Einstein hoped that underneath the Heisenberg principle there was still real determinism lurking. You'd never be able to get to it, but he hoped/assumed that, say, an electron still had a real, finite position with real momentum, etc.

He was wrong. In the absence of a definite interaction, the electron is like a little wave. It can go down two tunnels at once as a wavefront and make interference patterns with itself coming out both tunnel ends. Or, you can detect which way the electron goes, and the interference patterns vanish.

The experiment is usually done with photons, but Feynman discussed an electron version in his lecture series. Anyway, the un-collapsed wave function is like Schrödinger's alive/dead cat. It's as indeterminate as you can get.

[PatrickHenry]

In the absence of a definite interaction, the electron is like a little wave. It can go down two tunnels at once as a wavefront and make interference patterns with itself coming out both tunnel ends. Or, you can detect which way the electron goes, and the interference patterns vanish.

I've never liked QM. I haven't studied enough to denounce it, and I suppose that would be wildly foolish, given all the experimental evidence. But I just don't like it. So I ignore it. I am grateful that QM also ignores me. Sort of a stand-off.