The situated cognition movement in the cognitive sciences, like those sciences themselves, is a loose-knit family of approaches to understanding the mind and cognition. Cognition both stems from and generates the activities of physical individuals located in particular kinds of environments. Cognitive extensions, like house extensions, come in a surprising variety of forms. Some are truly, massively, staggeringly transformative, and others are content to project a previously existing theme. The first dimension concerns the nature of the non-neural resources that are incorporated into extended cognitive behaviors, dispositions, and activities. Such resources may be natural, technological, or sociocultural in nature. The second dimension concerns the durability and reliability of the larger (extended) system. Human agents exhibit both a metabolic and a cognitive organization. But whereas the former depends heavily on expensively maintained and policed organismic boundaries, the latter looks prone to repeated bouts of seepage.