Bell's Theorem
The point here is that the debate between Einstein and Bohr over reality - i.e., whether indeed an independent, external reality exists apart from the observer ("Is the moon there when you're not looking?") - moved from a philosophical debate to a scientific one: with Bell's theorem, it became possible to test the two metaphysical assumptions, i.e., the Einsteinian assumption of a local reality (independent of the observer, etc.) vs. the Copenhagen Interpretation of q.m. (see p. 94)
In particular, Bell's theorem demonstrates a contrast between the correlation to be found between measurements on twin particles:
if local reality is correct, the correlation will lie between -2 and 2;
if q.m. is correct, the correlation (e.g., for detectors at 45 degrees) = 2.83
These numbers mean, notice:
...the quantum world is more highly correlated than any world that depends on a local reality or locally operating hidden variables. (112)
The Experiments:
Briefly, the experimental work confirms the q.m. prediction, not the correlation predicted for local reality.
Implications:
While contemporary physicists/scientists may wish to ignore the "metaphysical" questions and implications surrounding "nonlocality" as now demonstrated via Bell's theorem and the Aspect experiments - Peat suggests that this effort at ignorance is parallel to an earlier reponse, namely, the response to Newton's conception of gravity as "action at a distance." (126)
Indeed, the demonstration of nonlocality is a fundamental paradigm shift out of Newtonian mechanics:
...physics had been wedded to locality, to systems that were well defined within their own particular regions of space and time, and to interactions that involved the transmissions of physical energy across space. The idea of nonlocality appears to deny this most basic fact of everyday experience, for it suggests that distant systems can be connected in a totally new way - a way in which distance no longer seems to matter. (127)
Among the many implications which Peat discusses, let me stress those under the heading "A Connected Universe" (156ff.)
Most generally, quantum mechanics appears to force us to recognize the limits of the "classical" Cartesian/Newtonian atomism and mechanistic picture of the world. While this picture works at a certain scale of reality ("between" the subatomic and the relativistic) - it is not an accurate account of all of reality, nor of "reality" at its most fundamental level.
Rather - if q.m. is correct, "reality" is unitary and connected in ways that correlate nicely with, for example, the direct experiences of connectedness reported in all religious traditions (cf. Peat, 158f.)
