Epiphylogenesis is a term coined by Bernard Stiegler to describe the sudden appearance in the history of life of a third kind of memory, in addition to: (1) genetic memory, organized in and transmitted via the DNA molecule and remaining unchanged over the course of the life of the organism; and (2) epigenetic memory, retained within the organs of the nervous system and recording (and forgetting) experiences lived by the individual, but lost with the organism’s death. These two “endosomatic” memories do not communicate, but epiphyologenetic memory, which is organized outside the individual organism’s own body, as organized inorganic matter, can both: (1) be conserved beyond the life of the individual; and (2) form a milieu of memory between individuals and across generations. Such an epiphylogenetic milieu—characteristic of a form of life that is no longer just biological, but technical, that is, exosomatic—is cumulative, but it can also, to a greater or lesser degree, stabilize in space and time, giving rise to enduring forms no longer of species but of kinds or idioms, processes, and phyla of territorial and cultural cohesion that also form epochs. Stiegler argues that the epiphylogenetic supports of memory are also supports of processes of idealization. This projective and imaginative aspect of epiphylogenesis means that it amounts to the advent of a new form of life, based on an exosomatic evolution operating not through biological automatisms or the accumulation of lessons lived by the individual itself, but also through the inheritance of a past that the individual has not lived, opening up, beyond the circuit of instincts, a libidinal economy of desire. The notion of epiphylogenesis is an intervention not just in the scientific fields of biology or archaeology or anthropology, but in philosophical considerations of the very possibility of formulating the conditions of knowledge, and amounts to a claim that there is no way of finally separating scientific and philosophical perspectives on the question of memory. For Stiegler, the fundamental motivation for the development of the concept of epiphylogenesis lies in his observation that the industrialization of epiphylogenetic memory and projection have set off a process that is destructive of both the accumulation of knowledge and the economy of desire.