Social individuals are social entities having a distinctive individuality, often signaled by the use of a proper name to designate them. This article proposes an account of social individuals based on the notion of a mental file, understood as a repository of information about a single individual. First, I consider a variant of the puzzle of the ship of Theseus in which the object having problematic identity conditions is a social individual, namely, a rock band. Then, I argue that we (...) can figure out such identity conditions by considering the mental files concerning this band. In conclusion, I outline a version of social constructionism according to which the existence of social individuals like bands depends on mental files about them. (shrink)