 Block and Stalnaker argue in some detail that the likely candidates for what to hold constant all give the wrong results. Consider how we might find the diagonal proposition associated with Oscar’s belief that water is wet. Suppose that a belief is, or is associated with, a mental analog of a sentence. We will suppose that, like a sentence, a mental token can be identified separately from its meaning. Then Oscar’s mental token, like the sentence “Water is wet,” could, in some possible mental language, mean that dogs have fur. Now if in diagonalizing we consider all possible worlds centered on someone who possesses the same mental sentence as Oscar’s water-sentence, regardless of its meaning, we get a diagonal proposition that is much too unconstrained to serve as a narrow content. We surely do not want to say that the narrow content of Oscar’s belief that water is wet has the value True in a world that contains no remotely watery substance, but in which dogs are furry and the mental token in question means that dogs are furry.