Language and thought

We can attribute intelligible thoughts to someone on the basis of their behaviour, or on the basis of what they say about them.

In the case of behavioural attribution, we always have Kripkean ambiguities. If someone explicitly claims to believe something, we can only doubt whether they do by doubting whether they are an honest and competent interlocutor. This doubt, if it is radical, cannot intelligibly be expressed in any conversation with them, since it is exactly whether we can have a conversation with them that we doubt.

A belief attribution can be incoherent for different reasons. The belief might be incredible, in the context of the behavioural evidence. It might be incoherent in the conversational context - e.g. a self-attribution of the kind instantiated by Moore's paradox: If someome persistently appears to claim to have a belief which we cannot intelligibly attribute to them, our conversation with them breaks down - we no longer know what they are talking about.

I think there are beliefs that cannot be attributed to anyone because to have the mental equipment to have the belief would also make the belief incoherent. A belief that it isn't possible to talk might be like this. Someone who had this belief would have to (a) understand what people thought they were doing when they spoke to one another and (b) believe that they were failing.

It would only be possible to meet criterion (a) if one knew how to talk. We might think this could be like knowing how to cast a horoscope, without believing the outcomes. But to know how to talk is to know, very generally (with a certain acceptable error rate), what is true and false - what it is appropriate and inappropriate to say. (b) cannot be an appropriate thing to say in any playable language game, so a person who knew how to talk (in the relevant context) would also assert that (b) was false. Someone who believed it wasn't possible to talk, but knew how to 'mimic' talk in this way, would sound as though they believed it was possible to talk - they would sound just like everyone else.

We might say 'but they would be lying'. This claim is not ruled out, but finding grounds for it is complicated by the fact that it depends upon certain interpretations which have an irreducably normative element to them. It is not simply a 'matter of fact' whether someone is an honest interlocutor or not, particularly where the evidence of their dishonesty is not acknowledged in any conversation we have with them.