Although many critics have noticed the prevalence of negation in Faulkner's prose, not enough attention has been paid to the unique function and logic of pairing negated statements with positive ones. This essay posits that the rhetorical figure of dirimens copulatio ("not x, but y") is raised to the organizing principle of Faulkner's Absalom, Absalom! This strategy of negating a prior statement to shape and clarify a positive one is not only locally employed at crucial moments in the novel, but it also characterizes the novel's wider structure of presenting a sequence of competing and exclusive claims. This essay considers the logic and poetics of dirimens copulatio and discovers that it, in Faulkner's use, employs metalinguistic negation (negating on the basis of assertibility, not descriptive truth). Tropological consideration of dirimens copulatio also reveals it as illustrative of the asymmetrical dynamism underlying interrelations among the novel's central tropaic registers. By applying the conclusions about the metalinguistic logic and tropaic function of dirimens copulatio to the wider narrative's narratological, political and authorial stakes, I show how dirimens copulatio enables an imbalanced fusion of the novel's racial, legal, sexual, and political ontologies.