Out of Nowhere

The two fundamental pillars of physics for over 100 years have been quantum theory and general relativity, but their unification at short distances remains elusive, both technically and conceptually. This work is a philosophical investigation of the second kind of problem, and in particular of the striking fact that in many approaches to 'quantum gravity' classical spacetime structures are not merely quantized, but arguably absent—so that spacetime is not merely a classical limit, but 'emergent'. This issue is not only central to the problem of quantum gravity, but of deep significance for our philosophical understanding of physical reality, promising a conceptual revolution at least as profound as Einstein's. Nick Huggett and Christian Wüthrich explore the question of spacetime emergence, for philosophers of metaphysics and science, and argue for spacetime functionalism as the answer to seeing how something non-spatiotemporal could ever appear as space and time. More technical chapters investigate the issue in detail for causal set theory, loop quantum gravity, and string theory, and the book also serves as a philosophical introduction to those theories for philosophers of physics. Out of Nowhere helps physicists clarify what new conceptual framework—not resting on space and time—may be necessary to achieve a theory of quantum gravity. This book also shows philosophers how the world may not be spatiotemporal at root, and what kind of a world we might then live in.

Nick Huggett (PhD Rutgers University, 1995) is an LAS Distinguished Professor at the University of Illinois Chicago. His specialties are the philosophy of science and the philosophy of physics. His early publications concentrated on quantum field theory, and theories of space from antiquity to the present. In recent years he has been collaborating with Christian Wüthrich (University of Geneva) on a project on the philosophy of quantum gravity. He has written or edited six books and over 50 articles on these topics. Christian Wüthrich (PhD University of Pittsburgh, 2006) is Associate Professor of Philosophy at the University of Geneva, where he heads the Geneva Symmetry Group. He works primarily in philosophy of physics, philosophy of science, and metaphysics. From 2006 to 2015, he was at the University of California, San Diego. He is the Co-Director (with Nick Huggett) of the Beyond Spacetime research project on the philosophy of quantum gravity. He has edited six books or special issues of journals and has published over 40 articles.