It seems to me that in all these cases, so far as we are not merely talking of _facts_, but of true _ideas_, that the "idea" which we truly say to be true at one time and false at another, is merely the idea of a _sentence_--that is, of certain _words._ And we do undoubtedly call _words_ "true." The words "I am at a meeting of the Aristotelian Society" are true, if I use them now; but if I use the same words to-morrow, they would not be true. The words "George III is king of England" were true in 1800, but they are not true now. That is to say, a given set of words may undoubtedly be true at one time, and false at another; and since we may have ideas of words as well as of other things, we may, in this sense, say the same of certain of our "ideas." We may say that some of our "ideas" (namely those of words) are true at one time and not true at another. But is it conceivable that Professor James _merely_ meant to assert that the same _words_ are sometimes true at one time and false at another? Can this be _all_ he means by saying that truth is mutable? I do not think it can possibly be so. No one, I think, in definitely discussing the mutability of truth, could say that true ideas were mutable, and yet mean (although he did not say so) that this proposition applied _solely_ to ideas of words. Professor James must, I think, have been sometimes thinking that _other_ ideas, and not merely ideas of words, do sometimes change from true to false. And this is the proposition which I am concerned to dispute. It seems to me that if we mean by an idea, not merely the idea of certain words, but the kind of idea which words express, it is very doubtful whether such an idea ever changes from true to false--whether any such idea is ever true at one time and false at another.