Philosophical Foundations of the Edge of the Universe

The EDGE project is a philosophical study of the concept of an edge or boundary as it relates to the universe on the largest scale. But what does an edge refer to when the region is the entire universe? Despite widespread use of this boundary, there is little agreement about how to interpret it: some have called it “heuristic”; others “incoherent’; and still others a “law of nature”. There is no unified perspective on the general nature of boundary conditions in physics, and no agreed-upon conceptual foundation for how they apply to the entire universe.We propose an ambitious but credible programme to overcome this challenging problem. We begin with a classification of the properties, uses, and epistemology of boundaries as they are generally used in physics, from the separation of mind and world to the interaction of two coupled systems, and over a wide range of theories. We then turn to cases in which the boundary of the entire universe plays a substantial role in the frontiers of physics. These threads will form the basis for a general framework for understanding boundaries in physics, establishing shared features as well as the dimensions along which they differ. This will finally allow us to produce the first general analysis of what the edge of the universe means in physics: its ontology, its uses, and how we know about it.The pay-off of this project is a path-breaking new analysis in philosophy, which establishes a major new account of our universe at its farthest fringes. In physics, it stands to help clarify the pathway for those physicists actively developing the frontiers of science by using boundaries of this kind. More generally, it will establish a novel, accessible account of our place in the universe in comparison to the farthest reaches of our imagination. The ambition of the EDGE project is to produce such an account that is philosophically rigorous, scientifically sound, and still manages to capture a sense of wonder about the cosmos.