 In contrast, most classical explications of reduction developed in the philosophy of science treat the reduction relation to be primarily instantiated by representational entities, such as theories or models. Building on these two lines of thought, one can, following Van Gulick (2001), draw a distinction between representational and non-representational relata of the reduction relation, and accordingly between representational and ontological reduction. Intuitively, the conditions on an appropriate model of ontological reduction require the identification of a specific sort of intrinsic similarity between non-representational objects, such as properties or events. In contrast, the conditions on an appropriate model of representational reduction require the identification of a specific sort of intentional similarity; if one representation reduces to another, it does so because of a similarity in what, and maybe how, these representations represent.