The whole René Girard’s thought is based on the single hypothesis of the mimetic desire. Human beings imitate themselves in behavior and in desires themselves as well. Following the classical interpretation of Girard and imitation, we could say that the mimetic desire theory might then be an obstacle to the construction of our own identity, as we lose it as long as we imitate models. Through Spinoza's thought and the concept of mimetic rationality, we argue that Girard's concept of mimesis is, on the contrary, absolutely compatible with a conception of identity placed as a half-way house between ipseity and alterity. Therefore, we should analyze a constant movement between differentiation and identification in order to demonstrate Girard's concept of identity builds an identity understood as distance or diffèrance.