Mathesis is a research group based at the Complutense University of Madrid. Mathesis’ research interests span over all areas of theoretical philosophy (mainly: philosophy of logic, metaphysics, epistemology, philosophy of language, philosophy of mathematics) as well as on several aspects of historical interest (mainly: history of theoretical philosophy and of philosophically significant logic and mathematics), but, as it transpires from the group’s name, they are always informed by the methodological assumption of trying to make progress on the target problem with the substantial aid of formal methods (be these drawn from logic, mathematics or the empirical sciences), with the understanding that the employment of such methods is not an end in itself, but is instrumental to an overarching informal philosophical argumentation conducted with the strictest standards of informal rigour and clarity familiar from the analytic tradition in philosophy. Through seminars and reading groups conducted in a very informal and constructive environment, the group also places a special emphasis on the advanced training of young researchers, helping them to hone their philosophical skills and master formal methods.