  We have seen enough to appreciate the main ontological differences that divide reductive and non-reductive realists, and even some of the differences that divide non-reductivists among themselves. As we indicated earlier, in the later Middle Ages these differences tend to emerge in the context of the debate over whether relations are identical with their foundations. As we also indicated, however, we have to be careful not to assume that how philosophers answer this question provides an infallible guide to their positions. For although reductivists typically affirm that relations are identical to their foundations, and non-reductivists typically deny it, there are some reductivists who side, at least verbally, with the non-reductivists on this question. Thus, the later Harclay, as we are interpreting him, is a reductive realist—he not only rejects the existence of sui generis relational properties, but maintains that in paradigmatic relational situations, substances are related by their ordinary, non-relational accidents. Nonetheless, Harclay denies that relations are identical with their foundations, since he thinks this would amount to saying that relations can be straightforwardly identified either with ordinary accidents taken by themselves or with pairs of such accidents taken jointly.