[CraigS]

Originally Posted by sjastro

There is no "conflict" between the two theories. QM is an evolution of classical physics. It has hasn't replaced classical physics but takes it to a more fundamental level.

Yes .. again, I can whole heartedly see this also.
(A first for CraigS, eh ? … woo hoo ! …)
.. However, I'm afraid quite a few others don't, though.

Originally Posted by sjastro

The slit experiment is explained classically by treating light as a wave. QM extends this to wave/particle duality.

So then, perhaps the discontinuities made obvious when we compare 'the fundamentally quantum system' with the 'fundamentally classical system', were always there in the classical model, but were unknown and unrecognised ?… And when QM came along, it did expose the discontinuities .. but these were always present because of the ways Classical was attempting to explain wave and particle dynamics ?

I know its a subtle difference, but I hope others might see that there's been a huge amount of effort expended to unify 'two different worlds' by asking very deep questions like: "why the behaviours of the big and the small don't match up ?", when it could simply have appeared this way because the descriptions of wave and particle dynamics in classical physics were incomplete somehow ?
(I think we're on the same tracks here, also).

Originally Posted by sjastro

Bohr came up with a "semi classical" or "classical/QM hybrid" which explained the spectral lines. This was however part of the evolution of classical physics to QM.

Fair enough, too … and its interesting to note that we still refer to the differences, (discontinuities really), as somehow a function of some different behaviours, encompassed by the labels: "QM" and "Classical".

I mean, how often is "QM behaviour" referred to as "spooky" or "weird", seemingly to evoke an alluring perception of something which QM provides us with over classical ? (This is a perfect breeding ground for nutters who for example, hijack QM terminologies to suit their own malicious intents).

Cheers