The philosophy of causal set theory

TL;DR

This paper explores the philosophical implications of causal set theory, addressing issues like the nature of spacetime, the concept of time, and structural realism, and discusses how these impact our understanding of fundamental physics.

Contribution

It offers a philosophical analysis of causal set theory, proposing spacetime functionalism, examining the nature of time, and connecting structural realism with causal set metaphysics.

Findings

Spacetime may fundamentally disappear at the smallest scales.

Classical sequential growth dynamics suggest a possible passage of time.

Structuralist interpretation aligns well with causal set theory and philosophy of science.

Abstract

This article presents the most interesting philosophical issues as they arise in causal set theory. The first concerns the apparent disappearance of spacetime at the fundamental level. It shows how the looming empirical incoherence is averted if we adopt spacetime functionalism. Second, classical sequential growth dynamics rekindles hope for a fundamental passage of physical time compatible with relativistic physics. The article argues that this hope is faint at best, as a block view offers the most natural interpretation of dynamical causal set theory. Third, causal set theory admits a very natural structuralist interpretation, enabling a fruitful interaction between debates in philosophy of science concerning structural realism and the metaphysics of causal sets.