Two Questions

Quantum theory is famous, if for nothing else, than for the various raging debates about the interpretation of quantum theory. One of the issues which has been bugging me in this debate for a while is that I think that sometimes the combatents are actually debating different questions. In particular I would like to make the distinction between (1) the reconcilliation of the classical world with the quantum world and (2) the consistency of post-quantum theories with the quantum world.
In the first question, we ask how it is that the classical world of probabilities arises from the quantum world of amplitudes. Once we say that quantum theory is describing what is going on, then this question I think is important. And I also think we have lots of good reasons to believe we understand at least a little about the transition from quantum to classical. It’s totaly consistent to hold the point of view that there is nothing mysterious about the quantum world, that’s just the way it works, and if we are unconfortable with it, it is because we never directly experience it. In this case, what needs to be explained is how our classical world emerges from quantum theory.
The second question is a different and more challenging question. It asks what kind of theories exist which can reproduce quantum theory (exactly, or perhaps in some appropriate limit.) Often this question gets bungled up with the first question. In other words, we think of finding a deeper theory as finding a classical theory. But the deeper theory need not have anything to do with the quantum/classical transition. In fact, perhaps one of the greatest biases in thinking about deeper theories is that we implicity try to give them classical properties. But this doesn’t have to be the way it works.
Now, when I hear the many debators in the great quantum interpretation wars, the conversation sounds kind of funny. Like, Alice: “Pizza is better than hamburgers!” Bob: “Vegans eat lettuce.” So if you see me laughing when a consistent historian meets a Bohmian realist, you’ll now know why.