Schopenhauer, On the Fourfold Root of the Principle of Sufficient Reason [p. 154]: “Indeed, there are ideas which never find words, and alas these are the best.”
But how does he know that these are the best? By definition he doesn't. But he can't write "...and alas I suspect that these are the best", because this would be a comment upon his own suspicions--about himself and his desires--rather than an observation about certain ideas. Of course, in the whereof-we-cannot-speak game, there are only our own projections, desires, yearnings, which is no good for Schop's purposes. Insufficient.