Debate brings in that unequaled form of incentive for all action which psychologists call “social pressure” and which here means nothing more than the desire to excel a fellow-being in some line of endeavor. When debating we concentrate, and we do so without conscious effort. We are too interested in defeating our opponent to wander from the subject. We are forced to think rapidly. Not least of all, we are compelled to think articulately. But with all its advantages, debate is one of the most potent sources of prejudice. In the heat of controversy, we adopt any and every argument that comes handy. Every statement of our opponent is considered only in the light of how it can be refuted. We are willing to use almost any objection against him, so long as we believe he will see no flaw in it. It is of utmost importance that we find how to avoid these pitfalls. The first thing we must do is to adopt a complete change of attitude toward an opponent’s arguments. Whenever we meet with a fact which we would not like to cite in a debate; because, to put it mildly, it would not help our side; we should carefully investigate that fact. We should consider whether if true it changes the aspect of things. We should get rid of the idea that in order to vindicate our side we must answer every contention our opponent advances. For this opponent of ours will very likely be a man in full possession of his senses; at least some of his arguments will be rational. When they are, we should be willing to acknowledge it. Their truth does not necessarily make his side right. His arguments may be irrelevant; they may be outbalanced by some other reason or reasons. Attempts to prove too much are liable to put us into the position of the lawyer whose client is alleged to have been sued for putting a hole in a borrowed umbrella. The lawyer proved first, that his client did not borrow the umbrella; second, that there was a hole in it when he got it; third, that there was nothing the matter with it when he returned it.