It seems to me that there is a mechanistic cognitivist account of the shark implicit in TSRM's account. The idea is that the shark detects the electric field F, then infers (perhaps on the basis of an implicit assumption that if there is an electric field F, then there is probably something edible) that there is something edible. By cognitivist lights, inference can be mechanistic, since inference is the kind of thing a computer can do and computers are mechanistic devices. This is the account TSRM are evidently trying to forestall in the following passage:
To predicate of the shark (a) 'detects electric field of type F' and (b) 'takes to be an edible thing' is not to refer to two different states of affairs, one (viz. (b)) that is reached from the other (viz. (a)) by an inference. Rather, it is to make reference in two ways to a single state of affairs of the shark-niche system.So, here is what seems to me to be the lay of the land. It seems to be common ground to both cognitivists and TSRM that the shark detects the electric field F. Then, the issue that separates them is how this detection relates to taking there to be a fish present. The cognitivist answer is that the detection of the field and taking there to be a fish present are related by inference; one is among the premises for a conclusion of the latter. The TSRM answer is that the detection of the field and taking there to be a fish present are identical.
What I have been challenging is the adequacy of the TSRM account.
Andrew won't like the cognitivist answer, but that's not the same as claiming that I don't have one or that there isn't one.