Hume's Pivotal Argument, and His Supposed Obligation of Reason

Abstract:Treatise 1.4.1 argues that whenever we assess our probability of error, "we are oblig'd by our reason" to consider also the probability of error in that assessment, leading to a fatal regress which—but for irresistible nature—would extinguish all belief. The argument plays a huge role in the Treatise, and has recently attracted many defenders, rejecting the previously standard objection that iterated reflection need not imply reduction of probability. This paper, however, presses a more fundamental objection—that there is no obligation of reason to iterate in the first place—something obscured by the failure of previous analyses to focus on specific examples. Unlike the Treatise, Hume's Enquiry of 1748 is richly illustrated with examples, making it likely that he himself would have encountered these problems. And there are traces in the Enquiry of a fundamental change of view, corroborating the significance of this argument for his philosophical development.