Discussion should be one of the most important things in the world, for it is almost our only arena of thinking. It is here that all the jumble of ideas and impressions that we get from reading and watching are dramatically placed in conflict. Here only is there a genuine challenge to put them into some sort of order. Without discussion intellectual experience is only an exercise in a private gymnasium. It has never been put to the test, never had to give an account of itself. It is some such motive that impels people to discussion; though they are too often content with the jousting of pasteboard knights. But a good discussion is not only a conflict. It is fundamentally a coöperation. It progresses towards some common understanding. This does not mean that it must end in agreement. A discussion will have been adequate if it has done no more than set the problem in its significant terms, or even defined the purpose that makes such a setting significant. You turn up things in your mind that would have remained buried without the incision of some new idea. The effort to say exactly what you mean, sharpening your idea to the point that will drive home to others, is itself invigorating. A good discussion tones up your mind, concentrates its loose particles, gives form and direction. When all say exactly what they mean, then for the first time understanding--the goal of discussion--is possible. Discussion demands a mutual trustfulness, a mutual candor. But this very trustfulness makes discussion vulnerable. It is particularly open to the attack of the person who sees in the group a forum. The physical signs of such a misinterpretation are familiar. The eye becomes slightly dilated, the voice more orotund. The suggestion develops into an exposition, the exposition into an apologia or recrimination. Discussion is slain. Another enemy is the person who sidetracks a sentence and then proceeds in a leisurely way to unload its freight into his own wagon. But in a good discussion the traffic is kept constantly moving in both directions along a rather rigid line of track, and the freight arrives somewhere. Some people have a fatal gift of derailment. Wit is perhaps the most common means. Discussion has no greater enemies than those who can catch an idea and touch it off into a puff of smoke. Wit should salt a discussion but not explode it.