Beckett’s aggressiveness in crossing generic lines paradoxically accompanied a keen sensitivity to genre and medium differences that often constrained his writing. My argument here is that this combination of abandon and respect was founded in a recognition not just of formal differences in art but of differences in the ways we think. In the wake of groundbreaking work by Jerry Fodor and Howard Gardner, there has been a great deal of research advancing (and qualifying) a modular conception of how the mind evolved and how it continues to work in modern humans. This work puts new light on both the formal differences between mimesis and diegesis, and Beckett’s very interesting combinations of the two in his later work.