Why is Materialism central to Physics?

Question

The realist interpretation of the Uncertainty principle posits that reality is independent of the mind of the observer, therefore all objects must objectively have a pre-existing value for any possible measurement before the measurement is made. But because of the combination state of a quantum event (Schrodinger’s cat being simultaneously dead and alive before observation) there can be no pre-existing value for a possible measurement before the measurement is made, therefore no "thing" has a predefined existence in an unobserved state, which contradicts Materialism and reduces it to absurdity, i.e.that all things are composed of material, and that all emergent phenomena are the result of material properties and interactions, reality consists entirely of physical matter that is the sole cause of every possible occurrence, *(which cannot be true, according to realism, if no "thing" has a predefined existence in an unobserved state).

So if the Realist interpretation of the Uncertainty principle reduces Materialism to absurdity, why is Materialism still central to Physics?

Answer 1

The Copenhagen interpretation of quantum mechanics seems to imply that there is some important rôle for "observers" in the collapse of the wave function. Schrödinger gave his cat argument in an attempt to refute the Copenhagen interpretation by demonstrating that it leads to something ridiculous (a cat simultaneously dead and alive, and only "collapsing" to one state or another when the human opens the box).

As far as I know this argument has nothing to do with the uncertainty principle. The uncertainty principle is not mystical or particularly controversial. It is simply the statement that position and momentum are duals, and uncertainty principles also occur in classical systems (for example: the length and frequency of a sound are dual variables, the shorter a sound the more spread out its frequency spectrum must be, and a tone of a single frequency must be extremely long.)

I think almost all physicists are realists, as described in @MauroALLEGRANZA's comments, but they don't necessarily agree about what is real and what is just a model of reality. An interpretation of quantum mechanics makes philisophical assertions about what is and isn't real. If you look at the Wikipedia article about interpretations you will see that there are a dozen or so that are discussed and debated, and each makes different assertions about whether the wave function is "real" or just a mathematical convenience that models some other reality. They also all make different assertions about whether wave function collapse is real or is just an illusion brought about by quantum decoherence. Probably the most important sentence in the wikipedia article is:

No experimental evidence exists that distinguishes among these interpretations.

What most realists agree on, I think, is that there is something external to our minds, and that we all share a similar set of perceptions of things in the real world. That is: there are experiments we can perform and repeat and which we will all agree on the measured results.

Answer 2

What you have written about the uncertainty principle is false. In quantum physics, a system can be described in terms of Hermitian operators that change over time and these are called Heisenberg picture observables. When you do a measurement the result you see is not an observable but rather a real number that corresponds to one of its projectors. The reality that exists before the observations is described by the Heisenberg picture observables, not by a single number. See

http://arxiv.org/abs/1109.6223

and

http://www.quiprocone.org/Protected/DD_lectures.htm.

I don't understand what position you're trying to refute since you haven't explained it and for all I know that position may be wrong, but your argument against it is wrong.