Why Time has a Direction

with Kadri Vihvelin

Abstract

The direction of causation is the direction of contingent counterfactual dependence.   The temporal asymmetry of counterfactual dependence gives causation its temporal direction.  That asymmetry is explained by the fact that the dynamical laws of nature are logically irreversible functions from partial states of the world onto other partial states.   Though these irreversible laws are locally indeterministic, they sum to global determinism.  This combination of global determinism and local indeterminism gives rise to counterfactual asymmetry and gives causation and time a direction.  That direction is independent of the direction of entropy.   The direction of contingent counterfactual dependence-- and hence causation--  is time's arrow.

nb. Originally posted as Irreversible Laws and the Direction of Time on 11/10/2018