Social philosopher Matthew Rachar conducts research on theories of collective action at Freie Universität Berlin. His project “Unifying Solidarity” will investigate the fundamental nature of solidarity, as this concept is often understood in vastly different context-dependent ways. The European Research Council will finance the project for five years with an ERC Starting Grant worth 1.485 million euros. The goal of ERC Starting Grants is to support outstanding early-career scholars who wish to establish their own research groups or set up independent projects.

Matthew Rachar has taught and conducted research at the Department of Philosophy and Humanities at Freie Universität Berlin since 2024. Prior to this, he was a lecturer at the Department of Philosophy, Douglas College, Canada, and a postdoctoral researcher at the Institute of Philosophy, University of Vienna, Austria. His main areas of expertise include action theory, ethics, social and political philosophy, philosophy of science, philosophy of mind, and experimental philosophy.

A key focus of Rachar’s current research is a theory of shared agency, which suggests that individuals who form a collective intention mutually influence each other in a way that gives rise to normative commitments. He proposes that shared agency is not merely based on coordination, but that it instead changes the relationship between participants by producing interpersonal obligations.

Approaches to Analyzing Solidarity

Rachar’s latest project “Unifying Solidarity” builds on his previous research on collective action and social obligations, taking as its starting point the observation that solidarity as a concept is understood in a myriad of different ways, be it a special relationship, an emotion, or a moral virtue. The project argues that these diverging interpretations are all based on a common foundation: solidarity is a value expressed in the interdependent commitments of people who share a fate.

Rachar plans to develop a comprehensive theory of solidarity that reveals its conceptual structure as well as its moral and political implications using an innovative approach that synthesizes concepts from a variety of disciplines including value theory, philosophy of action, and metaethics, as well as the empirical methods of experimental philosophy. The main objectives of the project are to explain the relationship between solidarity and shared agency; to develop a descriptive account of the norms of solidarity; to provide a normative account of why and when those norms bind; and to evaluate the rationality of choosing solidarity.

“The project aims not only to advance philosophical debates, but also to offer a framework for navigating current societal and political issues. It will defend the current salience of solidarity in intellectual and activist circles, while also contributing to a new understanding of how solidarity contributes to a life well lived,” says Rachar.