Our sensory and motor capacities depend on more than just the workings of the brain and spinal cord; they also depend on the workings of other parts of the body, such as the sensory organs, the musculoskeletal system, and relevant parts of the peripheral nervous system (e.g., sensory and motor nerves). It seems natural to think of cognition as an interaction effect: the result, at least in part, of causal processes that span the boundary separating the individual organism from the natural, social, and cultural environment. One thing to say that cognitive activity involves systematic causal interaction with things outside the head, and it is quite another to say that those things instantiate cognitive properties or undergo cognitive processes. Bridging this conceptual gap remains a major challenge for defenders of the extended mind. Situated cognition is a many-splendored enterprise.