This paper begins with the proposal of a "pedagogy of concept" according to Deleuze and Guattari. On this basis, I emphasize and explore the assertion that every thought demands relational traces" as their internal condition". Among the relational traces defined by this pedagogy of concept, I selected "friend" as a character who distinguishes a given thought. I try, after that, to define, generally what friend and the scene of friendship in Plato's, Nietzsche's, Heidegger's and Foucault's philosophies are.
Deleuze; Guattari; Philosophy; Concept; Friendship