MDC (2000) describe mechanisms as working from start- or set-up conditions to termination conditions. They insist that it is impoverished to describe the phenomenon as an input-output relation because there are often many such inputs and outputs from a mechanism and because central features of a phenomenon might be neither inputs nor outputs (but rather details about how the phenomenon unfolds over time). Darden, appealing to the example of protein synthesis, often associates the phenomenon with the end-state: the protein (Darden 2006). Craver (2007), following Cummins (1975) and Cartwright (1989), often speaks of the phenomenon roughly as a capacity or behavior of the mechanism as a whole.