These ecumenical characterizations each include the four basic elements and are designed to make the characterization more inclusive. MDC’s insistence on the regularity of mechanisms is abandoned, for example, to accommodate mechanisms that work only once or that work irregularly (Skipper and Milstein 2005; Bogen 2005; see also Section 2.1.2 below). Bechtel and Abrahamsen’s emphasis on the “functions” is abandoned to accommodate mechanisms that serve no end and to distance mechanism from this loaded term so often opposed to mechanism (although see Craver 2001a; Garson 2013; Maley and Piccinini forthcoming; see also Section 4.5 below).