Keeping HEC in CHEC: On the Priority of Cognitive Systems

According to the hypothesis of extended cognition (HEC, hereafter), human cognitive processing extends beyond the boundary of the human organism. 2 philosophy of cognitive science; HEC is supposed to reveal something important about human beings' core cognitive faculties and, in doing so, reshape the study of human cognition. Although many authors have reacted to HEC with reasoned skepticism, 2 HEC has able champions, Andy Clark among them. In a recent paper, " Curing Cognitive Hiccups: A Defense of the Extended Mind, " 3 Clark responds to various criticisms of HEC, targeting my concerns in particular. 4 In this essay, I clarify and expand upon my objections, arguing that Clark's defenses come up short. all page references are to this paper unless otherwise indicated. 3 I. The natural-kinds argument and the Parity Principle In " The Extended Mind, " Clark and David Chalmers (C&C, hereafter) make the following claim: If, as we confront some task, a part of the world functions as a process which, were it done in the head, we would have no hesitation in recognizing as part of the cognitive process, then that part of the world is (so we claim) part of the cognitive process (" The Extended Mind, " p. 8). This has come to be known as the Parity Principle (PP, hereafter). In " Hiccups, " Clark accuses HEC's critics of founding one of their foremost concerns on a misinterpretation of PP (pp. 165-66). 5 The criticism at issue is focused on significant dissimilarities between internally realized cognitive states and those external states purported to be cognitive. As Clark sees things, we critics wrongly take PP to entail a fine-grained similarity between internal and external cognitive states, if any of the latter there be, which explains why we are put off by the many dissimilarities. 4 This diagnosis misses the mark badly. In the paper in question, CHEC, I explicitly set out to criticize C&C's (1998, pp. 13-14) argument from natural—or causal-explanatory—kinds. According to the distinctive premise of C&C's argument, cognitive science benefits from construing its causal-explanatory kinds in such a way that many external and internal states are of the same natural kind or instantiate the same theoretically relevant cognitive property. In response, I offered C&C a choice: characterize the relevant causal-explanatory kinds in terms of fine-grained functional properties (in terms of the reaction times they support, for instance) or instead opt for a …