Chapter 4 first follows Descombes' inquiry into the notion of the self that culminated in a specific interpretation of Wittgenstein's theory of rule-following. After rejecting this interpretation, the author develops his own by showing how Wittgenstein points to the bodily character of rule-following. In the third section, he scrutinises the bodily nature of sense-constitution by looking into perception in the domain of art. It becomes clear that constitution always involves passivity, and that it should, therefore, be understood as the creative-passive activity of an embodied subject. In Sect. 4.4, this is connected with Merleau-Ponty's notion of perception as the model of praxis, our bodily being in the world. This analysis of perception helps to understand the nature of the subject of sense-constitution and rule-following. With Merleau-Ponty, this subject is characterised as Je peux, a notion that is later replaced by its ontological counterpart J"en suis. Finally, Sect. 4.5 returns to Descombes' reading of Wittgenstein, one last time. Instead of a conventionalist reading of the latter's notion of "customs", the author argues that an interpretation that emphasizes the meaning of our embodied being in the world is crucial to understand how to follow a rule.