According to Derrida, the European self-understanding marking the name “Man” is governed by eschatology and teleology. Man is that being on its way towards its proper end. The times of science seemed to Kant and others to be evidence of just such progress. For Freud, by contrast, the great scientific achievements of Copernicus, Darwin and Freud have cumulatively contributed a series of de-centring blows to our “self-love”. This paper explores the nature of great scientific achievements, and raises the possibility of a further devastating blow to Man, this time in the twentieth century, and connected to the name of Marx.