  The second mark of the mental that Adams and Aizawa take to preclude systems like Otto+ notebook from counting as cognitive raises issues concerning the identification of scientific domains. If one supposes, reasonably enough, that the objects, processes, properties, etc. that fall into the domain of a particular science do so in virtue of sharing particular features, then one should expect the same for the domain of cognitive science. The parts, properties, and activities taking place in brains do seem to share important features, features that explain how it is possible to identify brains in newly discovered species, how they differ from igneous rocks, and so on. But now suppose that cognitive systems can be extended in ways that Clark, Chalmers and Wilson have argued. Such systems would now contain constituents that could not possibly fit into the domain of a single science. Extended systems might include notebooks, or pencil and paper, or tools of just about any sort. “[F]or this reason,” Adams and Aizawa argue, “a would-be brain-tool science would have to cover more than just a multiplicity of causal processes. It would have to cover a genuine motley” (2010, 76).