Causation, Reversibility and the Direction of Time

Abstract

When experimental evidence of the violation of Bell’s inequality began to appear in the late 1970s and the earlier 1980s, some scientists and philosophers wondered whether it would be possible to find a common cause for the correlation between pairs of spin-1/2 particles involved in these experiments. Some put forward proposals to the effect that a superluminal connection might be involved, while others, because of the alleged violation of special relativity by signals moving faster than light, suggested that backward causation is responsible for the correlation in the sense that the outcomes of measurements causally determine the preparation of the state of a pair of spin-1/2 particles. The whole discussion suggests, I believe, that we do not have a clear grasp of the concept of causation, causal processes and reversibility and the conditions under which they meaningfully apply to physical phenomena.