- Jun 12, 2015
(Report by Professor Elie During)
Session 1: I gave a general introduction to some of the big issues underlying the philosophical reception of relativity theory, following a distinction between: a) epistemological issues such as the function of a priori cognitive structures in our knowledge of the universe, b) metaphysical issues related to fundamental concepts such as space and time, coexistence and connection, identity and becoming, which constitute the core of any philosophy of nature.
On the epistemological front, I emphasised the difference between the neo-kantian approach advocated by Cassirer and the neo-positivist doctrine of Reichenbach. The concept of conventional "coordinative definition" was examined as an alternative to the traditional conception of the a priori. From that perspective, the relativity of simultaneity appeared to be a product of the ultimately arbitrary nature of the definitions involved by our measuring methods. The conventionalist strategy is in agreement with certain "deflationist" interpretations of the philosophical impact of Einstein's theory, downplaying the startling claims regarding space and time as a mere artefact of measuring procedures that does not affect space and time "in themselves" (Alain's stark criticism of "Einsteinian" philosophers runs along the same lines). This is not Reichenbach's view, however. At the heart of his account of the relativity of simultaneity lays a realist claim about the objective (frame-independent) structure of causal connections within the universe.
This offered a natural transition to the topics examined in Session 2, which focused on the ways certain philosophers redefined the metaphysical and cosmological background of their philosophy of nature to accommodate Einstein's theories. Both Bergson and Whitehead thought that Einstein's main contribution to philosophy was not to criticise general assumptions regarding space and time (such as the absolute nature of simultaneity), but to open the ways for new adventures in thought. Some time was spent on familiarising ourselves with Whitehead's intriguing views on the meaning of "time" in a context where "events" constitute the basic spatio-temporal ingredients of nature.
In order to see this, a "toy-model" of the special theory of relativity was presented in Session 3, emphasising two main aspects exemplified, respectively, by the principle of relativity and by the principle of light according to which the speed of light is a limiting factor in the propagation of any causal influence across space (this is illustrated by the existence of an absolute speed limit, invariant under all transformations from one perspective to another). The first principle is a principle of equivalence: it states the equivalence of a class of interchangeable perspectives on the world. Negatively, it states that there is no privileged point of view on the universe (and thus, no absolute space, no absolute motion). The second principle is a principle of reality in Freud's sense: it states that in order for real connection to obtain, time is needed for a causal influence to propagate from one point to another. Connection takes time. Negatively: there is no instantaneous action at a distance (and thus, no absolute "present"). The consequences of conjoining these two principles were evaluated from a philosophical point of view, with special emphasis on the non-intuitive character of physical interactions through space and time. Finally, drawing on Bachelard's ideas, we considered some ontological consequences of relativity theory―more particularly the way physical objects come to be determined by the interplay of perspectives, rather than as an underlying, pre-given substance waiting to be uncovered. There is, in his own terms, a constant "interference"―a relation of co-determination―between reality and reference, objectivity and perspective. Here again, epistemological issues appear essentially linked with metaphysical ones.