Fifteen years ago, Sharon Street and Richard Joyce advanced evolutionary debunking arguments against moral realism, which purported to show that the evolutionary history of our moral beliefs makes moral realism untenable. These arguments have since given rise to a flurry of objections; the epistemic principles Street and Joyce relied upon, in particular, have come in for a number of serious challenges. My goal in this paper is to develop a new account of evolutionary debunking which avoids the pitfalls Street and Joyce encountered and responds to the most pressing objections they faced. I begin by presenting a striking thought experiment to serve as an analogy for the evolution of morality; I then show why calibrationist views of higher-order evidence are crucial to the evolutionary debunking project; I outline a new rationale for why finding out that morality was selected to promote cooperation suggests that our moral judgments are unreliable; and I explain why evolutionary debunking arguments do not depend on our having a dedicated faculty for moral cognition. All things considered, I argue, evolutionary debunking arguments against moral realism are on relatively secure footing – provided, at least, that we accept a calibrationist account of higher-order evidence.