Truth values in Quantum Mechanics

It’s pretty much the same mistake that all the “realists” are doing all the time. They are imagining that they can assign truth values to all questions that could be in principle answered by experiments. (In some way, they give answers “No” or “zero” to all the other questions that were actually not addressed by the measurement.) But quantum mechanics prohibits that. If one assigns classical truth values (or real values) to some operators, one can no longer assign truth values (or real values) to “complementary” (not mutually commuting) operators and questions they represent. Instead of the correct statement that “the value of \(N_a\) isn’t determined if one measures \(L\) instead”, they say that it is zero which is just wrong.

— No particle upon a quantum field means no information

— Lubos Motl

2015.06.03 Wednesday ACHK