Abstract
During the last ten years John Beatty, Elisabeth Lloyd and I have argued that the semantic conception of theories is, in the context of biological theorizing, a richer conception of theory structure than the syntactic ("received view") conception. Specifically, I have argued semantic conception of theory structure better represents the structure of evolutionary theory and the relationship of this theory to phenomena. One aspect of the semantic conception that is in need of greater attention is the nature of explanation on this conception. In this paper, I argue that the semantic conception provides a richer mo accurate account of scientific explanation, in particular, of evolutionary explanations. In essence, I argue that explanation involves an appeal to numerous theories in addition to the putative explanatory theory. Employment of these theories is not formally possible in a syntactic conception but is in a semantic conception.