All along his researches, Halbwachs addressed the issue of causality, as he did for social space and social time (see in the present volume, Chapter 1, “Collective Memory”). For the young philosopher introduced to Kant's Critique de la raison pure by his two masters Henri Bergson and Émile Durkheim, involved in the European neo-Kantian movement of the beginning of the twentieth century, like his German homologous, Ernst Cassirer.

Causality, time, or space where a priori to be investigated, if not like Mauss and Durkheim in 1903 (and then Durkheim, 1912) for the two last, but at least scrutinizing causality by means of mathematical improvements related to probabilities or philosophy of science. Three steps may be found in his inquiries. First, there were the two dissertations (1913a, 1913b), the core on the working-class conditions of life and the complementary one on Quetelet's theory of average man. Second, Halbwachs left notebooks where we can find his peregrinations among the works of earlier contributors to the history of the mathematics of probabilities, or reflexions on very recent publications like for instance this comment on some information he got after the publication of Werner Heisenberg's article on his theorem of uncertainty in quantum physics (1927), left in his first note book (94):