> how do we know that the decision on which particle has which spin did not happen during separation itself It's difficult to explain concisely, but John Stewa

> how do we know that the decision on which particle has which spin did not happen during separation itself It's difficult to explain concisely, but John Stewart Bell wrote a nice albeit lengthy essay on this exact question: https://cds.cern.ch/record/142461/files/198009299.pdf https://cds.cern.ch/record/142461/files/198009299.pdf