An examination of Hull's claims about the nature of interactors, replicators and selection, with special attention to how the genetic material realizes the first two types, and a critique of Hull's attempt to apply the theory of natural selection to the explanation of scientific change, and in particular the succession of theories. I conclude that difficulties attending the molecular instantiation of Hull's theory are vastly increased when it comes to be applied to memes.

This Ph.D. thesis provides a pilosophical account of the structure of the evolutionary synthesis of the 1930s and 40s. The first, more historical part analyses how classical genetics came to be integrated into evolutionary thinking, highlighting in particular the importance of chromosomal mapping of Drosophila strains collected in the wild by Dobzansky, but also the work of Goldschmidt, Sumners, Timofeeff-Ressovsky and others. The second, more philosophical part attempts to answer the question wherein the unity of the synthesis consisted. I argue (...) that it exemplifies a weak of form of explanatory unification. (shrink)