This brings us to another rationale for separating erotic art and pornography that is very popular among art historians (and is somewhat reminiscent of Dutton’s expressed reservations towards eroticism in art). Art is necessarily multi-layered, it is argued, whereas pornography is one-dimensional; it has only one job to do and therefore lacks the formal and structural intricacy, the cognitive complexity, and interpretive openness of art (see, for example, Webb 1975: 6; Mahon 2005: 14; Wallace et al. 2007: 15). But while the Isenheim Altarpiece and Liberty Leading the People may indeed be very complex works, there is good reason to believe that the insistence on the simplicity of pornography is itself the result of an oversimplification. Let us examine this claim in more detail.