By comparing them, we demonstrate that there is the same kind of thing with similar features in both combinations, until the things that they are getting right have been shown set beside all the ones that they don't know; once the things in question have been shown like this, and so become models, they bring it about that each of all the individual letters is called both different, on the basis that it is different from the others, and the same, on the basis that it is always the same as and identical to itself, in all syllables.