The End of Matter? On the Early Reception of Relativity in neo-Kantian Philosophy

In his article La fin de la matière (1906) Henri Poincaré reported that according to many physicists “matter does not exist”, but he immediately added: “this discovery is not conclusive”. This caution was not shared by many philosophers, who swiftly saluted both special and general relativity as the sources of a new conception of physical objects. In my talk I will focus on Marburg neo-Kantianism (Cohen, Natorp and Cassirer) with its characteristic thesis of a progressive “dissolution” of matter modern physics, culminating in relativity. I will point out that this view predated Einstein’s discoveries and was rooted in a long epistemological tradition starting with Leibniz and Kant. Indeed, the neo-Kantian philosophers argued that this view was an originally Platonic insight that modern physics (and Einstein’s relativity in particular) eventually confirmed. I will show that this historical-philosophical perspective influenced the reception of relativity and left open a number of epistemological and scientific problems.