This volume presents thirteen original essays which explore both traditional and contemporary aspects of the metaphysics of relations. It is uncontroversial that there are true relational predications-'Abelard loves Eloise', 'Simmias is taller than Socrates', 'smoking causes cancer', and so forth. More controversial is whether any true relational predications have irreducibly relational truthmakers. Do any of the statements above involve their subjects jointly
instantiating polyadic properties, or can we explain their truths solely in terms of monadic, non-relational properties of the relata? According to a tradition dating back to Plato and Aristotle, and continued by medieval philosophers, polyadic properties are metaphysically dubious. In non-symmetric
relations such as the amatory relation, a property would have to inhere in two things at once-lover and beloved-but characterise each differently, and this puzzled the ancients. More recent work on non-symmetric relations highlights difficulties with their directionality. Such problems offer clear motivation for attempting to reduce relations to monadic properties. By contrast, ontic structural realists hold that the nature of physical reality is exhausted by the relational structure expressed
in the equations of fundamental physics. On this view, there must be some irreducible relations, for its fundamental ontology is purely relational. The Metaphysics of Relations draws together the work of a team of leading metaphysicians, to address topics as diverse as ancient and medieval reasons
for scepticism about polyadic properties; recent attempts to reduce causal and spatiotemporal relations; recent work on the directionality of relational properties; powers ontologies and their associated problems; whether the most promising interpretations of quantum mechanics posit a fundamentally relational world; and whether the very idea of such a world is coherent. From those who question whether there are relational properties at all, to those who hold they are a fundamental part of
reality, this book covers a broad spectrum of positions on the nature and ontological status of relations, from antiquity to the present day.
Anna Marmodoro is an Official Fellow in Philosophy at Corpus Christi College, University of Oxford. She specializes in ancient philosophy and contemporary metaphysics. She has published books and journal articles in both areas; and currently directs two major research projects: one on ancient and contemporary metaphysics of powers funded by the European Research Council, and one on the metaphysics of quantum entanglement, funded by the Templeton World Charity Foundation. David Yates holds a PhD from King's College London, and is currently a Senior Research Fellow at the University of Lisbon. He specialises in metaphysics (in particular metaphysics of science) with active research interests in the philosophy of mind (in particular neuroscientific approaches to consciousness). He is currently working on a 5-year project investigating the ontological status of spacetime in quantum gravity, funded by the Fundacao para a Ciencia e a Tecnologia (FCT).
1. Introduction: The Metaphysics of Relations ; 2. Relations as Plural Predications in Plato ; 3. Aristotelian vs. Contemporary Perspectives on Relations ; 4. Why Do Medieval Philosophers Reject Polyadic Accidents? ; 5. Positionalism Revisited ; 6. There Are (Probably) No Relations ; 7. External Relations, Causal Coincidence, and Contingency ; 8. Causal Relations ; 9. Is Powerful Causation an Internal Relation? ; 10. What a Structuralist Theory of Properties Could Not Be ; 11. The Foundations of Structuralism and the Metaphysics of Relations ; 12. Relations All the Way Down? Against Ontic Structural Realism ; 13. The Reality of Relations: the Case From Quantum Physics ; 14. Rovelli's Relational Quantum Mechanics, Anti-Monism and Quantum Becoming ; Bibliography ; Index