Clark and Chalmers’s paper has triggered a vigorous and continuing debate. Nonbelievers concede that numerous tight causal couplings between minds and environments exist, but they deny that it therefore makes sense to speak of an extended mind instead of a mind in a person that closely interacts with an environment. All things considered, they argue, thoughts remain in persons—never in objects like notebooks, however closely dependent a person could become on them. (Myin, 2010, p. 590).Saying that we deny that it makes sense to speak of an extended mind is not exactly how I think Adams, Aizawa, or Rupert put the matter. Instead, it is that the existence of tight causal couplings does not warrant the conclusion that the mind extends.
And, Adams, Aizawa, and Rupert admit that extended cognition is possible; only it does not appear to occur in the cases described advocates in the EC literature. So, the last part has to be read carefully. It is a bit strong maybe to say simply that thoughts remain in persons--never in objects like notebooks. On the other hand, the whole sentence has a correct parse, I think, if one is takes it to mean that thoughts do not extend in virtue of close causal couplings.
But, one should bear in mind that there are other arguments for EC, beside the close causal coupling sorts of arguments.