John N. Williams

I argue that Moore's propositions, for example, 'I went to the pictures last Tuesday but I don't believe that I did' cannot be rationally believed. Their assertors either cannot be rationally believed or cannot be believed to be rational. This analysis is extended to Moorean propositions such as God knows that I am an atheist and I believe that this proposition is false. I then defend the following definition of assertion: anyone asserts that p iff that person expresses a belief that p with the intention of causing relevant epistemic change in the cognition of an actual or potential audience

The preface paradox strikes us as puzzling because we feel that if a person holds a set of inconsistent beliefs, i.e. beliefs such that at least one of them must be correct, then he should give at least one of them up. Equally, if a person's belief is rational, then he has a right to hold it. Yet the preface example is prima facie a case in which a person holds an inconsistent set of beliefs each of which is rational, and thus a case in which that person has a duty to relinquish what he has a right to keep.

Moore’s paradox is the fact that assertions or beliefs such asBangkok is the capital of Thailand but I do not believe that Bangkok is the capital of Thailand or Bangkok is the capital of Thailand but I believe that Bangkok is not the capital of Thailand are ‘absurd’ yet possibly true. The current orthodoxy is that an explanation of the absurdity should first start with belief, on the assumption that once the absurdity in belief has been explained then this will translate into an explanation of the absurdity in assertion. This assumption gives explanatory priority to belief over assertion. I show that the translation involved is much trickier than might at first appear. It is simplistic to think that Moorean absurdity in assertion is always a subsidiary product of the absurdity in belief, even when the absurdity is conceived as irrationality. Instead we should aim for explanations of Moorean absurdity in assertion and in belief that are independent even if related, while bearing in mind that some forms of irrationality may be forms of absurdity even if not conversely