“Influence” – a physical account

Orly Shenker, Hebrew University of Jerusalem

It is well known, since Bertrand Russell’s “On the notion of cause”, that it is at least questionable if this notion has any role in the fundamental theories of physics, such as classical mechanics and quantum mechanics. Attempts have, however, been made to account for the notion of cause in statistical mechanics (classical and quantum), which is the theory that attempts to explain the temporally asymmetric macroscopic phenomena described by the second law of thermodynamics. In this context an attempt was recently made to provide a physical justification for the prevalent intuition that our actions influence the future but not the past. In this lecture I will describe this attempt, comment on the way the notion of influence there is connected with the notion of causation, and end by a critical assessment of this project and suggestions for alternative lines of thinking. (The lecture is not technical and is intended for audience with no acquaintance with the details of the theories involved).