Abstract
The thesis of this paper is that the causal theory of mental content (hereafter CT) is incompatible with an elementary fact of perceptual psychology, namely, that the detection of distal properties generally requires the mediation of a “theory.” I shall call this fact the nontransducibility of distal properties (hereafter NTDP). The argument proceeds in two stages. The burden of stage one is that, taken together, CT and the language of thought hypothesis (hereafter LOT) are incompatible with NTDP. The burden of stage two is that acceptance of CT requires acceptance of LOT as well. It follows that CT is incompatible with NTDP. I organize things in this way in part because it makes the argument easier to understand, and in part because the stage-two thesis—that CT entails LOT—has some independent interest and is therefore worth separating from the rest of the argument.