 Rupert (2009) argues that the best way to approach this is through the identification of a cognitive system, an identification that will rest heavily on how the sciences of the mind individuate such systems. The most plausible conception of a cognitive system, he argues, counts against extended mind. Another approach argues the need for identification of a mark of the cognitive—a set of necessary, sufficient, or necessary and sufficient, conditions for a process to count as cognitive. Reaction to this suggestion can be divided into three broad camps. First, there are those who think that a mark of the cognitive is not necessary. Just as we can study biology without a mark of the biological, and practice medicine without a criterion of the medical, we can also do cognitive science without a criterion of the cognitive (Allen 2017). Second, there are those who think a criterion of cognition is required, can be identified, and counts against extended mind (Adams 2010). Third, there are those who think a criterion of the cognitive is available and it supports extended mind (Rowlands 2009, 2010).