Could there have been unicorns?

Kripke and Dummett disagree over whether or not there could have been unicorns. Kripke thinks that there could not have been; Dummett thinks otherwise. I argue that Kripke is correct: there are no counterfactual situations properly describable as ones in which there would have been unicorns. In attempting to establish this claim, I argue that Dummett's critique of an argument (reminiscent of an argument of Kripke's) to the conclusion that there could not have been unicorns, is vitiated by a conflation of two superficially similar, though importantly different, claims. I then attempt to provide an account of the counter-intuitiveness of Kripke's position, arguing that the claim that there could not have been unicorns is best understood as a semantic, rather than metaphysical, claim. Finally, I provide a brief argument on behalf of the semantics of species terms that appears to underpin Kripke's position.