What can preemption do?

Abstract Evidential Preemption occurs when a speaker asserts something of the form “Others will tell you Q, but I say P,” where P and Q are incompatible in some salient way. Typically, the aim of this maneuver is to get the audience to accept P despite contrary testimony of others, who might otherwise be trusted on the matter. Phenomena such as echo chambers, conspiracy theories, and other political speech of interest to epistemologists today, all commonly involve evidential preemption, so the question arises: What effect, if any, does evidential preemption have on the audience's epistemic situation? In a widely discussed paper, Begby ( Philosophy and Phenomenological Research , 2021, 102 , 515) argues that evidential preemption can change the audience's epistemic situation in such a way that future testimony that Q, which would otherwise have been persuasive, can be rationally discounted to a significant degree. If so, evidential preemption is not a mere rhetorical flourish, but rather results in a rationally insulated belief that P. Since evidential preemption is a common feature of echo chambers and conspiracy theories, this would be a disturbing result. We bring good news: it is not so, at least not in the way Begby suggests. If evidential preemptions can change one's epistemic situation in a worrying way, it is a mystery how.