Conceptions of mechanisms due to Glennan (1996; 2002), Machamer, Darden, and Craver (2000), Bechtel and Abrahamsen (2005) have developed in opposition to the nomological approach to explanation. It is less emphasized, however, that these conceptions have also developed as alternatives to the causal perspective on explanation. In this paper, I argue that despite their distancing from the topic of causation, the mechanistic conceptions need to incorporate in their definitions of mechanisms the notion of insensitivity of causal relations that was examined by Woodward (2006).