| We live in a world of possibilities. Much of our practical life - planning, deciding, hoping and fearing - only makes sense before a background of possibilities for what the future will bring: real possibilities in concrete situations. Such real possibilities are dynamical; they vanish when they are not actualized. We learn about them through acting and interfering with the course of nature, and we commonly picture them via a tree of histories branching off from a single past course of events into multiple possible futures. Philosophical work on real possibility has been mainly technical, e.g., in the study of the semantics of the future tense, and other notions of possibility are more firmly embedded in philosophical argumentation. Descartes, for example, invokes the metaphysical possibility of a deceiving demon in his radical doubt, and laws of nature have been linked with the notion of physical possibility, e.g., in analyses of causation. Physical and metaphysical possibility are however static notions, and both are more abstract than real possibilities. In my research I will defend the thesis that real possibility is not just more concrete, but also more fundamental than physical or metaphysical possibility. I will show how a systematic exploration of branching-history-based real possibility leads to a new, unified philosophical conception of modality in which real possibility provides the foundation for other types of modality. I will approach the notion of real possibility from a theoretical perspective, deepening our understanding of its formal properties during the project's first two years. Based on this research I will then explore the interrelations between different types of modality, the metaphysical basis of real possibility, and its role in philosophy of science, especially with respect to the notions of determinism, causation, and a number of technical questions in the philosophy of physics. |
