A popular way for irrealists to explain co-identification—thinking and talking ‘about the same thing’ when there is no such thing—is by appeal to causal, historical or informational chains, networks or practices. Recently, however, this approach has come under attack by philosophers who contend that it cannot provide necessary and/or sufficient conditions for co-identification. In this paper I defend the approach against these objections. My claim is not that the appeal to such practices can provide necessary and sufficient conditions for co-identification, (...) but rather that it is a mistake to seek these in the first place. -/- . (shrink)