  The extended mind hypothesis has stimulated much interest in cognitive
science. However, its core claim, i.e. that the process of cognition can extend
beyond the brain via the body and into the environment, has been heavily
criticized. A prominent critique of this claim holds that when some part of the
world is coupled to a cognitive system this does not necessarily entail that
the part is also constitutive of that cognitive system. This critique is known
as the "coupling-constitution fallacy". In this paper we respond to this
reductionist challenge by using an evolutionary robotics approach to create a
minimal model of two acoustically coupled agents. We demonstrate how the
interaction process as a whole has properties that cannot be reduced to the
contributions of the isolated agents. We also show that the neural dynamics of
the coupled agents has formal properties that are inherently impossible for
those neural networks in isolation. By keeping the complexity of the model to
an absolute minimum, we are able to illustrate how the coupling-constitution
fallacy is in fact based on an inadequate understanding of the constitutive
role of nonlinear interactions in dynamical systems theory.
