A Lenient Causal Arrow of Time?

TL;DR

This paper reviews retrocausal toy-models that replicate quantum correlations, argues superdeterminism is unnecessary, and proposes a reformulation of quantum mechanics with a more lenient causal arrow of time.

Contribution

It introduces retrocausal toy-models that reproduce quantum correlations and suggests a new causal framework replacing the standard arrow of time.

Findings

Retrocausal models can replicate Bell correlations.

Superdeterminism is shown to be superfluous.

A lenient arrow of time could explain quantum phenomena.

Abstract

One of the basic assumptions underlying Bell's theorem is the causal arrow of time, having to do with temporal order rather than spatial separation. Nonetheless, the physical assumptions regarding causality are seldom studied in this context, and often even go unmentioned, in stark contrast with the many different possible locality conditions which have been studied and elaborated. In the present work, some retrocausal toy-models which reproduce the predictions of Quantum Mechanics for Bell-type correlations are reviewed. It is pointed out that a certain toy-model which is ostensibly superdeterministic -- based on denying the free-variable status of some of Quantum Mechanics' input parameters -- actually contains within it a complete retrocausal toy-model. Occam's razor thus indicates that the superdeterministic point of view is superfluous. A challenge is to generalize the retrocausal toy-models to a full theory -- a reformulation of Quantum Mechanics -- in which the standard causal arrow of time would be replaced by a more lenient one: an arrow of time applicable only to macroscopically-available information. In discussing such a reformulation, one finds that many of the perplexing features of Quantum Mechanics could arise naturally, especially in the context of stochastic theories.