Particle superposition?

Question

If a particle is a wave-form state when it is not being measured, how has it been even proposed that superposition/wave-form is a possibility, since measuring the particle in any form causes it to localize.

Answer 1

This comes down to your interpretation of choice with quantum mechanics. Einstein's original problem with QM as it emerged is that its nature forces you to reject one of two elements of classical physics that Einstein felt were necessary: scientific realism or locality.

Either we reject the notion that scientific mathematics represent something that actually exists (rather than simply being a mathematical abstraction that approximates reality without its constituent aspects necessarily being "real") or we reject the notion that causality is a local phenomenon.

One of the current problems in QM is that sometimes it's better to throw one out and sometimes it's better to throw the other out. The Copenhagen Interpretation, the most common interpretation of the wave function, abandons scientific realism -- the Copenhagen Interpretation says that there isn't any such thing as a "wave function" and that it's just a mathematical abstraction that happens to give correct answers, similar to how Feynman's many-paths integrals give correct answers without representing a "real" process.

(Note that John von Neumann reinterpreted, or misinterpreted, the Copenhagen Interpretation to begin the whole "consciousness causes collapse" nonsense that scooped up supporters like David Bohm and even John Wheeler for a while. Make no mistake, "consciousness causes collapse" interpretations are bad metaphysics and even worse "science." Its called "quantum quackery" by most physicists because of its pseudoscientific nature. I was just pointing this out because quantum quackery supporters claim that the Copenhagen Interpretation supports their garbage, but this is actually because von Neumann redefined it for that purpose -- incorrectly.)

Then we have something like the EPR paradox, i.e. quantum entanglement and quantum teleportation. With these phenomena it seems better to throw out locality and keep scientific realism.

This balance between scientific realism and locality bothered Einstein deeply, and for good reason I think. There are some attempts even now to reformulate QM so that we can keep both scientific realism AND locality. Decoherence is a giant leap in this direction, and its thought-father Roland Omnes works diligently to reconcile quantum physics with scientific realism and locality.

Answer 2

Read up on Quantum field theory (nothing in the quantum world ever makes 'common sense' :-) )