quantum mechanics: at another level (Introduction)

by rekastner , Wednesday, July 17, 2013, 08:13 (4149 days ago) @ dhw

Thanks for your questions about TI. You say:-"If I've understood this correctly, it means that quantum mechanics can only take on reality when it is within our own spacetime reality. Otherwise it remains an unreal potential. In that case, isn't it true that the theory does not describe "anything objectively real"? Besides, how can we ever know what is objectively real?"-Not exactly. Quantum mechanical entities described by the usual quantum states are objectively real physical possibilities, though they don't live in spacetime. However, they can become actualized within the spacetime manifold via transactions -- if that happens, they participate in the exchange of detectable energy and enter the spacetime world of appearance (the empirical world). So the theory does indeed describe something objectively real, it's just that 'real' is not equivalent to 'existing in spacetime'. It may help to remember for example that Plato thought of reality as having 2 levels -- the world of appearance and the underlying reality. In this case, spacetime is the world of appearance, while the quantum possibilities inhabit the underlying reality beyond the world of appearance. Another way to think of this is in terms of Kant's division of reality into (1) the phenomenal realm (spacetime) and (2)noumenal realm (that aspect of reality that is not observable). -The key here is to understand that the physical possibilities described by quantum states are real and they do objectively exist. They just don't exist 'within spacetime' and therefore can't be experienced directly. Remember that Heisenberg spoke of a 'strange new kind of reality somewhere in between an object and the idea of an object' or words to that effect. It is a kind of reality, even though not empirically observable.