 Another feature shared by (1)–(5) is that they all fail to meet a condition—discussed by C.D. Broad in his 1925—that an attribute must meet if it is to carve out a class of entities. If neutrality is to be a kind-forming attribute, it “must be a simple attribute, i.e., it must not be analysable into a conjunction or disjunction of other attributes” (Broad 1925: 23). If one accepts this kind of homogeneity constraint on neutral entities, all five criteria of neutrality proposed above fail to pick out a set of entities that are sufficiently simple or homogeneous to form a kind.