The chapter presents a conceptual framework that links the enaction of our intentions to the understanding of other people's intentions through the concept of "Presence", the feeling of being and acting in a world outside us. Specifically the chapter suggests that humans develop intentionality and Self by prereflexively evaluating agency in relation to the constraints imposed by the environment (Presence): they are "present" if they are able to enact in an external world their intentions. This capacity also enables them to go beyond the surface appearance of behavior to draw inferences about other individuals' intentions (Social Presence): others are "present" to us if we are able to recognize them as enacting beings. Both Presence and Social Presence evolve in time, and their evolution is strictly related to the three-stage model of the ontogenesis of Self introduced by Damasio (Proto-Self, Core Self, Autobiographical Self). More, we can identify higher levels of Presence and Social Presence associated to higher levels of intentional granularity: the more is the complexity of the expressed and recognized intentions, the more is the level of Presence and Social Presence experienced by the Self. In this framework, motor intentions and mirror neurons are at the basis of the intentional chain, but full intentional granularity requires the activity of higher cortical levels.