 At least some of these problems can be resolved by taking the very act of asserting a specific similarity between a model and a target as constitutive of the scientific representation. Giere (1988: 81) suggests that models come equipped with what he calls “theoretical hypotheses”, statements asserting that model and target are similar in relevant respects and to certain degrees. He emphasises that “scientists are intentional agents with goals and purposes” (2004: 743) and proposes to build this insight explicitly into an account of representation. This involves adopting an agent-based notion of representation that focuses on “the activity of representing” (2004). Analysing representation in these terms amounts to analysing schemes like