An Essay on the Logic of Warrant

Warrant' is whatever distinguishes knowledge from mere true belief. 'Fallibilism' is the view that false beliefs can have warrant. This dissertation evaluates a novel argument for Fallibilism. Chapter 1 introduces a puzzle about warrant, and uses it to generate the 'Best Solution Argument' for Fallibilism. This puzzle is the fact that the following three popular claims are incompatible: Infallibilism – Only true beliefs can have warrant. Egalitarianism – False as well as true beliefs can support knowledge. Preservationism – Inference does no more than preserve warrant. According to the Best Solution Argument, while Egalitarianism and Preservationism are plausible, Infallibilism is unjustified. Chapter 2 defuses two arguments for the nonexistence of warrant. The first, due to Stephen Hetherington, misconstrues 'externalist' and 'internalist' requirements on knowledge. The second, due to Michael Huemer, contains a questionable premise unsupported by available arguments. Chapter 3 argues that Infallibilism is unjustified. Most of this chapter assesses the two strongest arguments for Infallibilism. The first, rooted in work by David Lewis, infers Infallibilism from the oddity of 'concessive knowledge attributions.' I defend a novel account of epistemic possibility, and use it to develop a Fallibilist-friendly explanation of the relevant oddity. The second – the 'Luck Argument' – is due to Trenton Merricks and Linda Zagzebski. After improving this argument, I assess the two main objections to it. While the first fails, the second drives the Luck Argument's proponent to a questionable semantic theory for counterfactuals. Chapter 4 defends Egalitarianism. After making a prima facie case for it, I disable three objections to Egalitarianism. Two proceed from work on the 'Gettier Problem,' while the other proceeds from work on evidence by Peter Unger and Timothy Williamson. Chapter 5 considers Preservationism. After establishing an initial presumption in its favor, I evaluate three objections to Preservationism. Two proceed from recent work on memory and testimony, while the other invokes putative counterexamples. While the first two objections fail, the third succeeds. Chapter 6 draws two conclusions from previous chapters' findings. First, neither Infallibilism nor Fallibilism constitutes an adequacy condition on theories of knowledge. Second, Foundationalism about knowledge and warrant should be reconceived in terms of justification.