Greater than the parts: A review of the information decomposition approach to causal emergence

TL;DR

This paper reviews and extends a formal information decomposition approach to causal emergence, providing a quantifiable framework that links emergence to information about a system's evolution beyond its parts.

Contribution

It introduces a formal, empirically testable theory of causal emergence based on information decomposition, addressing interpretative issues and broadening its applicability.

Findings

The formalism quantifies emergence through information about system evolution.

It demonstrates the approach's utility across various scientific scenarios.

The framework clarifies interpretation issues related to causal emergence.

Abstract

Emergence is a profound subject that straddles many scientific disciplines, including the formation of galaxies and how consciousness arises from the collective activity of neurons. Despite the broad interest that exists on this concept, the study of emergence has suffered from a lack of formalisms that could be used to guide discussions and advance theories. Here we summarise, elaborate on, and extend a recent formal theory of causal emergence based on information decomposition, which is quantifiable and amenable to empirical testing. This theory relates emergence with information about a system's temporal evolution that cannot be obtained from the parts of the system separately. This article provides an accessible but rigorous introduction to the framework, discussing the merits of the approach in various scenarios of interest. We also discuss several interpretation issues and potential misunderstandings, while highlighting the distinctive benefits of this formalism.