A Modification of the Halpern-Pearl Definition of Causality

TL;DR

This paper proposes a simplified modification to the Halpern-Pearl causality definition that addresses previous issues, aligns with standard examples, and reduces computational complexity.

Contribution

It introduces a new, simpler version of the Halpern-Pearl causality definition that resolves known problems and improves efficiency.

Findings

The new definition handles classic causality problems effectively.

It reduces the computational complexity compared to previous definitions.

The approach aligns with intuitive causality judgments in standard examples.

Abstract

The original Halpern-Pearl definition of causality [Halpern and Pearl, 2001] was updated in the journal version of the paper [Halpern and Pearl, 2005] to deal with some problems pointed out by Hopkins and Pearl [2003]. Here the definition is modified yet again, in a way that (a) leads to a simpler definition, (b) handles the problems pointed out by Hopkins and Pearl, and many others, (c) gives reasonable answers (that agree with those of the original and updated definition) in the standard problematic examples of causality, and (d) has lower complexity than either the original or updated definitions.