Interdisciplinary approaches are useful because they help to clarify and overcome the blind spots inescapable in any scientific theory. Combining psychoanalytic and evolutionary accounts of the human psychic system can therefore have interesting outcomes. It is important in any interdisciplinary approach, however, to investigate the metaphysical and epistemological presuppositions that serve as background to the theories in question, and to investigate the potential for compatibility on that level. In this paper the metaphysical backgrounds of Freudian-Lacanian psychoanalysis and neo-Darwinian theory of evolution are analysed and tested as to their compatibility. It is argued that evolutionary psychology, in so far as it finds its inspiration in neo-Darwinian theory, is not compatible with psychoanalysis where it is inspired by the theory of complexly organized dynamical systems. One one side, there is a black-boxing of the structural and developmental conditions of psychic systems, and on the other, there is a focus on the ultimate causes, as distinguished from the proximate causes. Taking into account these incompatibilities, it is highly unlikely that evolutionary psychology will prove of much use to psychoanalysis, either in theory or in practice.