Title. Probabilities of Conditionals and Conditional Probabilities -- Revisited
Abstract. Lewis' (1976) triviality argument against The Equation (also known as Adams' thesis) rests on an implausible assumption about the nature of (epistemic) rational requirements. Interestingly, Lewis (1980) later rejected this assumption. In his discussion of the Principal Principle, Lewis makes a weaker and more reasonable assumption about the nature of rational requirements. In this paper, I explain how to apply the insights of Lewis (1980) to repair Lewis (1976). This leads to a more reasonable rendition of the equation -- one that is (a) immune to triviality and (b) a better candidate for a (bona fide) rational requirement.
