Sur les sources néokantiennes de la pensee épistémologique de Henri Poincaré

Abstract

Cassirer and other neo-Kantian philosophers have framed Poincaré’s philosophical thought in the neo-Kantianism, but without seeking its concrete historical genealogy. The influence of the philosopher Émile Boutroux, Poincaré’s brother-in-law, and his intellectual circle was proposed by Mary Jo Nye, in 1979, suggesting that Poincaré’s geometric conventionalism is linked to Boutroux’s idea of contingency of the natural laws. Recent studies inscribe Boutroux in French spiritualist neo-Kantianism and motivates a renewal of research on the French sources of Poincaré’s epistemological thoughts. In this paper I broaden the question: rather than considering the relation Boutroux-Poincaré in particular, I prefer to deal simultaneously with the report to the neo-Kantian movement, which requires consideration, in addition to the writings of Boutroux, of those of the most influential neo-Kantian French, Lachelier, and those of Helmholtz, which is the only neo-Kantian thinker quoted by Poincaré. Their thoughts on Kantian themes and idiosyncratic use of Kant’s allow us to detect readings that may have inspired the young Poincaré. This study illustrates the historical relationship between philosophers and scientists, at a time when the great scientists were not necessarily ‘savants-philosophes’.