Proponents of formal syntactic description respond by citing implementation mechanisms. Externalist description of mental activity presupposes that suitable causal-historical relations between the mind and the external physical environment are in place. But surely we want a “local” description that ignores external causal-historical relations, a description that reveals underlying causal mechanisms. Fodor (1987, 1994) argues in this way to motivate the formal syntactic picture. For possible externalist responses to the argument from implementation mechanisms, see Burge (2010b), Rescorla (2017b), Shea (2013), and Sprevak (2010). Debate over this argument, and more generally over the relation between computation and representation, seems likely to continue into the indefinite future.