 There are two significant consequences of this sort of analysis. First, with substances, it is standardly supposed that you are a member of the kind or not and there is no middle ground: you are a horse or you aren’t. (Because there is no opposite or contrary to horse, the only negative option a contradictory.) Again we can contrast this with other opposites: there is a middle ground between long/short, inside/outside, loud/quiet; and some things avoid the opposition altogether, e.g., my coffee mug is neither loud nor quiet. Casting a category as substantial, then, limits the available categories for classification. For example, suppose we understand ‘male’ substantively. If males are a substance kind, then everything is either male or not-male, with no middle-ground. But if, in practice, ‘not-male’ actually functions as a way of picking out females, then it would seem that everything must be either male or female, and there can be no space for genuine categories of people who are intersexed, or other-sexed, or for refusing to sex people at all. One strategy, then, for undermining the idea that a category is substantival is to highlight the multiplicity of individuals and categories “in between” the primary category and its implicit opposite. Category proliferation—the generation of a continuum or genuinely “mixed” categories—can loosen the grip of substantival assumptions (Butler 1987; Lugones 1994; Haraway 1988; Zack 1995).