The book defends a radical new theory of contingency as a physical phenomenon. Drawing on the many-worlds approach to quantum theory and cutting-edge metaphysics and philosophy of science, it argues that quantum theories are best understood as telling us about the space of genuine possibilities, rather than as telling us solely about actuality. When quantum physics is taken seriously in the way first proposed by Hugh Everett III, it provides the resources for a new systematic metaphysical framework encompassing possibility, necessity, actuality, chance, counterfactuals, and a host of related modal notions.
Rationalist metaphysicians argue that the metaphysics of modality is strictly prior to any scientific investigation; metaphysics establishes which worlds are possible, and physics merely checks which of these worlds is actual. Naturalistic metaphysicians respond that science may discover new possibilities and new impossibilities. This book's quantum theory of contingency takes naturalistic metaphysics one step further, allowing that science may discover what it is to be possible. As electromagnetism revealed the nature of light, as acoustics revealed the nature of sound, as statistical mechanics revealed the nature of heat, so quantum physics reveals the nature of contingency.
Alastair Wilson is Professor of Philosophy at the University of Birmingham and Adjunct Senior Research Fellow at Monash University. He was President of the Society for Metaphysics of Science in 2017-18, Honorary Secretary of the British Society for the Philosophy of Science in 2018-19, and is currently leading FraMEPhys, a five-year project on metaphysical explanation in physics funded by the European Research Council. He works in the emerging subfield of metaphysics of science, a branch of philosophy which draws on contemporary scientific discoveries to help answer ancient questions about the underlying nature of reality.