Why Explaining An Idea Is Essential For Clear Understanding
From 'On Friendship' by Francis Bacon Paragraph 6 (1625)

The second fruit of friendship is healthful and sovereign for the understanding, as the first is for the affections. For friendship maketh indeed a fair day in the affections from storm and tempests; but it maketh daylight in the understanding out of darkness and confusion of thoughts; neither is this to be understood only of faithful counsel, which a man receiveth from his friend; but before you come to that certain it is, that whosoever hath his mind fraught with many thoughts, his wits and understanding do clarify and break up in the communicating and discoursing with another, he tosseth his thoughts more easily, he marshalleth them more orderly, he seeth how they look when they are turned into words; finally, he waxeth wiser than himself, and that more by an hour's discourse than by a day's meditation. It was well said by Themistocles to the King of Persia, that speech was like cloth of Arras, opened and put abroad, whereby the imagery doth appear in figure [full outline], whereas in thoughts they lie but as in packs. Neither is this second fruit of friendship, in opening the understanding, restrained only to such friends as are able to give a man counsel; they indeed are best, but even without that, a man learneth of himself and bringeth his own thoughts to light, and whetteth his wits as against a stone, which itself cuts not. In a word, a man were better relate himself to a statue or picture than to suffer his thoughts to pass in smother.