It seems as though, however the outward circs. change, once the
word is fastened to a particular personal experience, it now retains its meaning; and that therefore I can now use it with sense whatever may happen.
     To say that I can't doubt whether [to say|I see] red is in a sense absurd as the game I play with the expression “I see red” doesn't contain a doubt of this form.
     It seems, – whatever the circumstances I always know now whether to apply the word or not. It seems, at first it was a move in a special game, but then it becomes independent of this game.
   (This reminds one of the way the idea of length seems to become emancipated from any particular method of measuring it.)