The Quantum Structure of Space and Time (293 pages)

50 The Quantum Structure of Space and Tame

postulate in quantum mechanics, have imagined, for purposes of argument, that

the universe is reproduced in many copies independent of one another. They

then look at the quantum mechanical behavior of each system and they show

that the statistical weight in this hypothetical set of universes, the statistical

weight of a given situation, is what is called the probability. In other words, the

calculation of the two things is the same. Therefore you do not have to worry.

You do not have to agonize about this independent probability postulate. It just

follows from identifying probability with the result of this artificially created

statistical situation. The second comment I would like to make is about the

so-called non-locality of quantum mechanics. I think it is simply a misnomer.

What people have noticed is that, if you try for example in the Einstein-Rosen-

Podolsky-Bohm experiment as performed by many people in the laboratory,

to interpret the results classically, then you would need either non-locality or

negative probabilities. But you do not interpret them classically. You interpret

them in quantum mechanics and in that case there is no non-locality of any

kind whatsoever.

D. Gross Especially since we use local quantum field theory to describe these

experiments.