Abstract
The disagreement between defenders and opponents of extended cognition is often framed in terms of constitution. The underlying principle of this discussion is what I will call the co-location principle: cognition is located where its constituents are located. The crucial question is under which conditions something is to be counted as a constituent of cognition. I will formulate three criteria of adequacy that an account of constitution must satisfy to be applicable to the dispute on extended cognition. I will evaluate different accounts of constitution as to whether they satisfy the criteria of adequacy. Three different accounts of constitution can be identified in the literature on extended cognition, which I will call property-based constitution, diachronic constitution, and mechanistic constitution. I will show that none of the accounts satisfies all three criteria. Thus, the search for the mark of constitution does not seem to be a promising strategy for defending extended cognition. I will briefly sketch a new strategy of how to deal with this situation.