Aristotle’s biology and contemporary evolutionary biology appear to be fundamentally at odds. Any comparative biology seeks to explain the fit and diversity of organismal form, but Aristotelian and contemporary biology do so in very different, evidently incompatible, ways. In this chapter, I argue for a reconciliation between the two biologies. Recent advances in evolutionary thinking suggest that the form of population thinking pursued by twentieth-century evolutionary biology must be augmented by an understanding of the ways in which organisms as adaptive, purposive entities contribute to adaptive evolution. Moreover, the phenomenon of adaptation cannot adequately be understood unless we take into account the ways in which an organism’s “way of life” structures its experience of its conditions of existence. The active role that organisms play in evolution is nicely captured in Aristotle’s concept of bios – way of life.