 Similarity and representation initially appear to be two closely related concepts, and invoking the former to ground the latter has a philosophical lineage stretching back at least as far as Plato’s The  Republic.[8]  In its most basic guise the similarity conception of scientific representation asserts that scientific models represent their targets in virtue of being similar to them. This conception has universal aspirations in that it is taken to account for representation across a broad range of different domains. Paintings, statues, and drawings are said to represent by being similar to their subjects, and Giere proclaimed that it covers scientific models alongside “words, equations, diagrams, graphs, photographs, and, increasingly, computer-generated images” (2004: 243). So the similarity view repudiates the demarcation problem and submits that the same mechanism, namely similarity, underpins different kinds of representation in a broad variety of contexts.