One very important consequence of the indefinability of good must be emphasized, namely, the fact that knowledge as to what things exist, have existed, or will exist, can throw absolutely no light upon the question as to what things are good. There might, as far as mere logic goes, be some general proposition to the effect whatever exists, is good, or whatever exists, is bad, or what will exist is better (or worse) than what does exist. But no such general proposition can be proved by considering the meaning of good, and no such general proposition can be arrived at empirically from experience, since we do not know the whole of what does exist, nor yet of what has existed or will exist. We cannot therefore arrive at such a general proposition, unless it is itself self-evident, or follows from some self-evident proposition, which must (to warrant the consequence) be of the same general kind. But as a matter of fact, there is, so far as I can discover, no self-evident proposition as to the goodness or badness of all that exists or has existed or will exist. It follows that, from the fact that the existent world is of such and such a nature, nothing can be inferred as to what things are good or bad. (§ 9 ¶ 1)