This chapter applies the concepts of the previous chapters to the analysis of life courses, addressing the question of causality and showing how spheres of activity help to identify the generality of social phenomena. Generality poses the more general problem of relations between processes, and that of causalities, which are considered here as articulations between processes. It also allows us to deal with the mechanisms associated with these causalities and the regularities they are supposed to explain. The categories proposed in this book can be used to account for a wide variety of situations, from the simple addition of micro-processes to a globally stable structure, to more massive, gradual changes or ruptures. In all cases, establishing causes, regularities and mechanisms involves characterizing relations between processes, and decoupling phenomena that integrate microsociological processes into processes that are more extensive in terms of mass, duration or generality.