The role which in our present case the name “B” plays in the expression “I expect B” can be compared with that which the name “Bright” plays in the expression “Bright's disease”. Compare the grammar of this word, when it denotes a particular kind of disease, with that of the expression “Bright's disease” when it means the disease which Bright has. I will characterize the difference by saying that the word “Bright” in the first case is an index in the complex name “Bright's disease”; in the second case I shall call it an argument of the function “x's disease”. One may say that an index alludes to something, and such an allusion may be justified in all sorts of ways. Thus calling a sensation “the expectation that B will come” is giving it a complex name and “B” possibly alludes to the man whose coming had regularly been preceded by the sensation.