In this dissertation I address three philosophical problems in the philosophy of biology united by the underlying, and interlocking, issues of the explanatory role of teleological, normative, and representational concepts in biology. In the first chapter, I argue that extant accounts of functions have foundered on a problem I dub the Dysfunction Dilemma, and I offer a way to move forward. Functions are of philosophical interest because the concept plays an important explanatory role in biology, and other sciences, but is apparently teleological and normative –an item’s function is its end, purpose, or goal, and a dysfunctional item is one that fails to realize a particular norm, performance of its proper function. Extant accounts of funct...