Bell's theorem/Wikipedia Lede

Bell's theorem is a ‘no-go theorem’ that draws an important distinction between quantum mechanics (QM) and the world as described by classical mechanics. This theorem is named after John Stewart Bell.

In its simplest form, Bell's theorem states:

Among experts in the field, a more formal (precise?) statement is:

Cornell solid-state physicist David Mermin has described the appraisals of the importance of Bell's theorem in the physics community as ranging from "indifference" to "wild extravagance". Lawrence Berkeley particle physicist Henry Stapp declared: "Bell's theorem is the most profound discovery of science."

Bell's theorem rules out local hidden variables as a viable explanation of quantum mechanics (though it still leaves the door open for non-local hidden variables). Bell concluded:

Bell summarized one of the more obscure ways to address the theorem, superdeterminism, in a 1985 BBC Radio interview:

Links

 * WikiJournal of Science/A card game for Bell's theorem and its loopholes
 * Bell's theorem (Wikiversity project page)