 Cummins (1975) criticized both Hempel and Nagel on the grounds that the proper target of explanation of biological function claims is not the presence of a trait, but the capacities of biological organs and organisms. Sophisticated capacities can be analyzed in terms of the contributions that their components make to those capacities. For example, the heart of a bilaterian animal pumps blood, which in this way contributes to the capacity of the organism to deliver oxygen and nutrients to its tissues. The heart itself can be further decomposed into parts (chambers, valves, etc.) which each play different functional roles in contributing to that organ’s capacity to pump blood. Among philosophers, this approach to functional analysis is most associated with Cummins (1975), although biologists have advanced similar ideas, sometimes independently (Hinde 1975; Lauder 1982), and indeed the approach can be traced much further back, as the quotation from William Harvey in the introduction suggests. Cummins’ ideas about functional analysis have been incorporated in recent discussion on mechanisms in the biological sciences (see the entry on  mechanisms in science).  For instance, Craver (2007) explicitly draws on Cummins (1975) in his account and is important for moving teleological descriptions down to the molecular level (see also, Craver 2001, 2013). 