Abstract
This article explores the sources of the concept of difference advanced by Deleuze and, in particular, the idea of a non-phenomenological difference, understood as internal difference. In the first part, Deleuze’s appropriation of the concepts of memory and duration proposed by Bergson is explored, as if it corresponded with a response to Heidegger’s systematization of Nietzsche, thus opening the concept of forces to others such as heterogeneity, relativity, and multiplicity. The second part contains a dicussion of the hypothesis according to which the immersion in the Bergsonian synthesis of time results in the justification for the reformulation of the eternal return as repetition, the distinctively deleuzian problem of internal difference, and the concept of virtual as the definitive sign of a new plane of immanence for thought. The article concludes by presenting the internal difference from the outside that overflows it and makes it mutate in the whole of Deleuzian philosophy.