@TimB Summoning you to symposium

"Even quantum mechanics (which many claim has a random element) seems to obey deterministic rules" ...possibly, but I get the impression that you are way behind on how determinism in QM works.

"the Double Slit Experiment for instance always gives a known result based on a probability distribution; NOT a 'slightly random' element as many claim. It should also be noted that the idea that summing the probability distributions of 2x single slits doesn't give the same result as the DSE because it doesn't take into account resonance. If you account for phase of waveform in the SSE results, you'd probably find that the sums DO match" ...

I think you're really missing something fundamental about the double slit experiment. What I'm about to say here, I should emphasize, is something that basically every introduction to quantum mechanics contains.

First off, the particle in double slit experiments doesn't actually matter. It could be something we think of as very wavy, like photons. But this works equally well with electrons, entire atoms, and molecules per actual experiments.

If you're talking about the waves, that's great... you're already doing quantum mechanics. But we don't measure waves. That electron/photon/molecule is detected when it hits a screen... we just see a spot on the screen.

In that sense, the thing we're measuring in a DSE behaves very particle-like. There's also another very important sense in which it's particle like that I'll get to later.

So when both slits are open, we see something wavelike; an interference pattern. That in itself isn't too surprising. But there's one important thing to note... the interference pattern seems to alternate in bright spots and dim spots. There are spots so dim, in fact, that no particles hit it.

Those spots are a major issue; because if you cover one slit up, you'll see particles hitting it.

The other particle-like feature is that each of these things... photons, electrons, atoms, molecules... are not indefinitely divisible like you would think a pure wave would be. Photons only come out in whole number multiples of particular energies corresponding to a wavelength; you never see "half" a photon, it's always a whole photon.

But you can send photons (or electrons/atoms/molecules) through the double slit experiment at so low of an intensity that they go through one at a time; if your frequency is low enough, you can separate them by seconds.

When you do this, you see the particles hit the screen, one at a time. As you keep sending them through, they will build up an interference pattern. So it appears like even individual particles interfere with themselves when you send it through.

It's a fundamental mistake to confuse quantum mechanics for just statistical classical mechanics. Behaviors exactly like this, that spite anything you could come up with that is classical, are ubiquitous in QM. They are the reason we have all of that complex math.

@HWalters: Leonard Susskind was originally a plumber before he got interested in physics.