There is no argument that the mind extends

On the basis of two argumentative examples plus their ‘parity principle’, Andy Clark and David Chalmers argue that mental states like beliefs can extend into the environment. I raise two problems for the argument. The first problem is that it is more difficult than Clark and Chalmers think to set up the Tetris example so that application of the parity principle might render it a case of extended mind. The second problem is that, even when appropriate versions of the argumentative examples can be constructed, the availability of a second, internalist parity principle precludes the possibility of inferring that the mind extends. Choosing which parity principle we ought to wield would involve deciding beforehand whether or not the mind can extend. Thus, Clark and Chalmers beg the question by employing their parity principle rather than the internalist one. I conclude that they fail to provide a proper argument to support the extended mind thesis.