Original: John Stewart Bell (28 June 1928 - 1 October 1990) was an Irish physicist, and the originator of Bell's Theorem, one of the most important theorems in quantum physics.
Simplified: John Stewart Bell (28 June 1928 â "1 October 1990) was an Irish physicist who made great contributions to quantum physics, and especially to the question of what Heisenberg's uncertainty principle really tells us about the world.