 Clark and Chalmers (1998) provide a canonical argument for state-oriented extended mind. Otto is in the early stages of Alzheimer’s, and to facilitate his engagement with the world he writes down what he suspects will be useful information in a notebook. Reading in a newspaper that there is a particular exhibition going on at the Museum of Modern Art, Otto looks in his notebook, and finds the sentence, “The Museum of Modern Art is on 53rd Street”, and, desiring to see the exhibition, duly sets off to 53rd Street. Clark and Chalmers argue, or are commonly taken to argue, that the sentence should be regarded as one of Otto’s beliefs. Their argument is predicated on a functionalist conception of beliefs as individuated by their functional roles. The sentence plays a functional role in Otto’s psychological economy that is, if not precisely identical, similar enough to the functional role of a belief in the psychology of an unimpaired subject for the sentence to qualify as a belief. If this is correct, it means that at least one of Otto’s beliefs lies in the notebook rather than in his head. As usually understood, this view qualifies as a form of state-oriented extended mind to the extent that it identifies a mental state (a belief) with an external structure (a sentence).