According to the thesis of the extended mind (EM) , at least some token cognitive processes extend into the cognizing subject's environment in the sense that they are (partly) composed of manipulative, exploitative, and transformative operations performed by that subject on suitable environmental structures. EM has attracted four ostensibly distinct types of objection. This paper has two goals. First, it argues that these objections all reduce to one basic sort: all the objections can be resolved by the provision of an adequate and properly motivated criterion—or mark—of the cognitive. Second, it provides such a criterion—one made up of four conditions that are sufficient for a process to count as cognitive.