Experiments motivated by Bell's theorem have led some physicists to conclude
that quantum theory is nonlocal. However, the theoretical basis for such claims
is usually taken to be Bell's Theorem, which shows only that if certain
predictions of quantum theory are correct, and a strong hidden-variable
assumption is valid, then a certain locality condition must fail. This locality
condition expresses the idea that what an experimenter freely chooses to
measure in one spacetime region can have no effect of any kind in a second
region situated spacelike relative to the first. The experimental results
conform closely to the predictions of quantum theory in such cases, but the
most reasonable conclusion to draw is not that locality fails, but rather that
the hidden-variable assumption is false. For this assumption conflicts with the
quantum precept that unperformed experiments have no outcomes. The present
paper deduces the failure of this locality condition directly from the precepts
of quantum theory themselves, in a way that generates no inconsistency or any
conflict with the predictions of relativistic quantum field theory.Comment: This paper is a much simplified, yet still rigorous, version of
quant-ph/0010047. The descriptive material is almost all new, and I believe
very clear, but the rigorous formal argument, now relegated to Appendices, is
the same as before. I consider it to be a new pape
