what are the benchmarks by which parity of causal contribution is to be judged? Here is the wrong way to answer this question. First we fix the benchmarks for what it is to count as a proper part of a cognitive system by identifying all the details of the causal contribution made by (say) the brain. Then we look to see if any external elements meet those benchmarks. Why is this the wrong way to go? Because it opens the door to the following style of anti-EM argument: we identify some features of, say, internal memory that are not shared by external memory, and we conclude that since the parity principle is not satisfied, EM is false. (Wheeler, 2010, pp. 30-31).There actually seems to me to be a lot going on here.
First, no one (Rupert, Adams, or Aizawa, in particular) want to fix the benchmarks by identifying all the details of the causal contribution made by the brain. At most, Rupert, Adams, and Aizawa want to fix the benchmarks by identifying all the cognitive details of the causal contribution made by the brain.
Second, it seems to me perfectly fine to ask, "If one were to fix the benchmarks by reference to the cognitive details of the brain, then would we find these same cognitive details realized in brain-body-world combinations?" The answer might be "no", but that does not mean that there is anything wrong with the question.
Third, bear in mind that, on the assumption that these fine causal details are multiply realizable, then it would not beg the question against EC. If the details are multiply realizable, then it is in principle possible they are realized outside the brain. Fineness of detail per se does not cheat the advocate of EC.
Fourth, and here is where Wheeler ultimately gets the conclusion he wants. He can say that, even though Rupert, et al., are right that the fine causal contribution is not extended (what a preposterous idea!), there is this other kind of causal contribution -- call it "coarse causal contribution"-- that is extended.
Yet, it is misleading to suggest that Rupert, et al. are asking "the wrong question". They are not begging the question. They are not asking an absurd question. The only thing is that it does not lead to the conclusion that Wheeler wants, namely, that there is some extended cognition.
So, I disagree with Wheeler's subsequent analysis:
To be clear, the Rupert-style argument under consideration is not suspect in virtue of being anti-EM, rather it is suspect because it begs the question against EM by assuming that II what counts as cognitive should be fixed by the fine grained profile of the inner. Such question-begging can be avoided, and Rupert's criticism resisted, if we adopt the following alternative strategy for saying what the benchmarks are by which parity of causal contribution is to be judged. First we give an account of what it is to be a proper part of a cognitive system that is essentially independent of where a candidate element happens to be located with respect to the internal-external boundary (however that boundary is to be determined). Then we look to see where cognition falls - in the brain, in the non-neural body, in the environment, or, as the EM theorist predicts will sometimes be the case, in a system that extends across all of these aspects of the world. (ibid., p. 31).But, Rupert, et al., are not begging the question on fine grained details. They are just asking a question to which the consensus answer now seems to be, "That kind of cognition does not extend". Moreover, by "extracting" one's benchmarks for cognitive parity from the brain exemplar does not prejudice the location of other realizations of that exemplar.