http://www.sifa.unige.it/wp-content/uploads/2012/01/BookAbstracts.pdf In this paper we will argue that there is a kind of epistemic authority that the second person has over my mental states, distinct from, and irreducible to, first-‐person authority. This authority has a double dimension. A weak one: the second person often.has an authority over the content of my mental states. A stronger one: the second person plays a constitutive role regarding the existence and first-‐personal access to some kinds of mental attitudes. Regarding the strong role played by second-‐person authority we will focus on two types of states: reactive emotions, such as resentment or gratitude, for which the second person plays a constitutive role during the period of introduction in practices of ascription of mentality, and intentions related to both joint action and action whose purpose is to make the agent intelligible. These intentions necessitate, during the whole life of the agent, a second person. We finish this paper contrasting our insistence on a constitutive role for the second person with the view, popular in the cognitive science, according to which some intentions and emotions are innate.