Solving Frege’s Puzzle∗

Our actions are a product of mental states that represent how the world is, how we want it to be, and so forth. Such is central to our conception of ourselves as rational agents. I suppose it is possible that this conception is simply wrong. Perhaps there are, as eliminativists have argued, no such things as beliefs and desires. Or perhaps there are, but these states are merely relations to uninterpreted formulae in some internal computational system. I am going to set such questions aside here and assume that our ordinary conception of our ourselves is not wholly mistaken. The question I want to discuss concerns the role played in this conception by the notion of representation, that is, by representational content. The question is: How must we understand the contents of mental states such as beliefs and desires if those states are to play the causal and explanatory roles envisaged for them?1 The question can be illustrated as follows. According to Frege (1984b, pp. 144–5), the reference of a sentence is its truth-value. Frege did not, however, take the content of a sentence to be its truth-values and, relatedly, he did not regard beliefs as relations between thinkers and truth-values. Such a view would widely be regarded as patently absurd. But why? One answer is that such an account fits poorly with our intuitions about the truth-values of sentences that attribute beliefs. If beliefs were relations to truthvalues, it might be said, then “N believes that S” and “N believes that P” would have the same truth-value whenever S and P had the same truth-value. Since each of us surely has at least one belief that is true and one belief that is false, every sentence of the form “N believes that S” would then be true. That does not accord with intuition. But this is a poor sort of objection. There is no reason to suppose that our ∗A somewhat shortened version of this paper appeared in the Journal of Philosophy 109 (2012), pp. 132–74. 1 The puzzle in which we’ll be interested can be formulated in various terms, and whether one wants to think of it as concerning psychological explanation, intentional laws, or mental causation is not, I think, critical for the discussion here. I’ll usually talk in terms of explanation, as that is how I’ve tended to think of it myself, but I’ll speak in other terms when that seems convenient.