Fictional and Impossible objects, Counterpossible reasoning and Thought experiments. A study of medieval theories of impossibility and their contemporary relevance.

Medieval philosophical and scientific language, for many centuries and across different traditions, has been overcrowded with entities and scenarios that are – or were thought to be – fictitious or utterly impossible. These are entities like chimeras, flying men, golden mountains, but also atoms, infinite lines, bodies moving in a void space or at an infinite speed. Incorporating these impossibilities in standard theories of inference, showing how impossible statements can be manageable through valid reasoning while producing interesting conclusions, is one of the greatest achievements of the medieval thought.FICTA proposes an innovative, comparative and interdisciplinary approach to investigate the notion of impossibility and its epistemic value in medieval logic, philosophy and science. The project’s main aim is to systematically assess the various ways in which philosophers and scientists in the medieval and post-medieval period theorized the use of counterpossible reasoning – that is, reasoning involving entities, assumptions or scenarios that are physically, metaphysically, or logically impossible. The project also aims to explore the parallels between these historical developments and the thriving contemporary debate related to the use of impossibility, fiction and imagination for epistemic purposes. FICTA’s approach will cross disciplinary boundaries, intersecting the history of medieval and postmedieval logic, medieval literature and art; the history of medieval and early-modern science, and contemporary logic and epistemology.The project’s guiding questions will be the following: How can we obtain new knowledge by starting from impossible assumptions? Which role do impossible entities and impossible assumptions have in the (history of) sciences and in our epistemic endeavor?