Are life forms real? Aristotelian naturalism and biological science

Aristotelian naturalism (AN) holds that the norms governing the human will are special instances of a broader type of normativity that is also found in other living things: natural goodness and natural defect. Both critics and defenders of AN have tended to focus on the thorny issues that are specific to human beings. But some philosophers claim that AN faces other difficulties, arguing that its broader conception of natural normativity is incompatible with current biological science. This paper has three aims. First, we consider a distinctive and nuanced critique of AN’s general understanding of natural normativity put forward by Tim Lewens. Second, after giving a defense of AN, we explore and evaluate Lewens’ proposed alternative view—Kantian projectivism about life forms. We present a problem for Kantian projectivism and suggest reasons for thinking that AN is, after all, the superior position. Finally, we clarify and explain how AN’s claims about life forms and our knowledge of them, relate to empirical observation and to contemporary biological science.