Lying and Certainty

In the philosophical literature on the definition of lying, the analysis is generally restricted to cases of flat-out belief. This chapter considers the complex phenomenon of lies involving partial beliefs – beliefs ranging from mere uncertainty to absolute certainty. The first section analyses lies uttered while holding a graded belief in the falsity of the assertion, and presents a revised insincerity condition, requiring that the liar believes the assertion to be more likely to be false than true. The second section analyses assertions that express graded beliefs, exploring how mitigation and reinforcement can alter the insincerity conditions for lying. The last section considers the case of lies that attack certainty (knowledge-lies), understood as attempt to alter the hearer's graded beliefs