It will be remembered that, at the beginning of Chapter XXI, four theories of truth were distinguished, of which I advocate the fourth, which is the correspondence theory. The third, that of coherence, was discussed and rejected in Chapter X. The second, which substitutes "probability" for "truth", has two forms, in one of which I can accept it, while in the other I must regard it as mistaken. In the form in which it merely says that we are never quite certain that a given proposition, expressed in words, is true, I accept it; but in the form in which it contends that the concept "truth" is an unnecessary one, I reject it. It seems to me that " 'p' is probable" is strictly equivalent to " 'p is true' is probable", and that when we say " 'p' is probable", we need some probability that this statement is true. I see no reason why an advocate of probability, as all that is practically attainable, should reject "truth" as it appears in the above statements. I shall therefore not controvert Professor Reichenbach's views, since I believe that, by a small modification, they can be rendered consistent with my own.