How is posthumanism to be theorized, approached, recognized? If traces of humanism haunt even the most extreme of incarnations of posthumanist thought, how should the 'post-' of posthumanism be understood? If tradition keeps coming back, if anthropocentrism will not be laid to rest, it is perhaps time to rethink what is to be done. Drawing principally on the theories of Jacques Derrida and Jacques Lacan, this essay intervenes in the posthumanist debate by sketching out a somewhat different approach to the problem. Taking Don Siegel's Invasion of the Body Snatchers as an example, I argue that the film's apparent humanism is always already being called into question from within. That is to say, humanism is forever becoming posthumanism. The t...