Extended mind, functionalism and personal identity

In this paper, I address one recent objection to Andy Clark and David Chalmers's functionalist argument for the extended mind thesis (EM). This objection is posed by Kengo Miyazono, who claims that they unjustifiably identify the original cognitive subject with the hybrid one in order to reach their conclusion about the mind extension. His attack consists of three steps: (a) distinguishing hybrid from traditional cognitive subjects based on the systems reply originally directed at Searle's Chinese room argument; (b) pointing out that the conclusion of the functionalist argument for EM must be rephrased to state that there are hybrid, and not extended, systems with widely realized mental states; and (c) arguing that functionalist EM cannot justify the assumption about the identity of these two kinds of subjects without circularity. I argue that Miyazono's main argument is ill-founded but that it, nevertheless, points out one important issue, namely, that we need further justification of the identity assumption, without which EM loses much of its flavor. Thus, I am going to challenge Miyazono's argument, provide a reinterpretation of the argumentation in the EM debate, defend the possibility of wide and extended selves, and offer a justification of the identity assumption, which I find crucial not only for vindicating EM but also for differentiating EM from other similar theses, such as the thesis about group minds.