This paper deals with some formal properties of objects that are supposed to be internal to persons, that is, mental structures and mental functions. Depending on the ways of talking about these internal objects, they will appear different. Two types of discourse will be presented, to be called the realist and the nominalist discourses, and for eachdiscourse I will focus upon the construction of `self'.The realist discourse assumes an identity between the person and his construction of himself. I will illustrate (...) this discourse in terms of Descartes' ideas on himself as a `thinking substance'. The nominalist discourse assumes an impossibility to attain this identity, and instead to imply a complementarity between the person and his self-construction. I will illustrate this discourse in terms of the problems both William James and Sartre discerned when a conscious person chases after his own consciousness (termed `judging thought' and `pour-soi' respectively). (shrink)