Causality Without Causal Models

TL;DR

This paper abstracts the Halpern-Pearl causality definition to apply it beyond traditional causal models, enabling broader and more complex causal reasoning including disjunctions, negations, and nested counterfactuals.

Contribution

It provides an abstract causality definition that extends applicability to various models and complex formulas, surpassing limitations of existing causal definitions.

Findings

Applicable to models with backtracking

Handles complex formulas involving disjunctions and negations

Enables abstract explanations beyond causal models

Abstract

Perhaps the most prominent current definition of (actual) causality is due to Halpern and Pearl. It is defined using causal models (also known as structural equations models). We abstract the definition, extracting its key features, so that it can be applied to any other model where counterfactuals are defined. By abstracting the definition, we gain a number of benefits. Not only can we apply the definition in a wider range of models, including ones that allow, for example, backtracking, but we can apply the definition to determine if A is a cause of B even if A and B are formulas involving disjunctions, negations, beliefs, and nested counterfactuals (none of which can be handled by the Halpern-Pearl definition). Moreover, we can extend the ideas to getting an abstract definition of explanation that can be applied beyond causal models. Finally, we gain a deeper understanding of features of the definition even in causal models.