In any fairly large and talkative community such as a university there is always the danger that those who think alike should gravitate together where they will henceforth encounter opposition only in the emasculated form of rumour that the outsiders say thus and thus. The absent are easily refuted, complacent dogmatism thrives, and differences of opinion are embittered by the group hostility. Each group hears not the best, but the worst, that the other group can say.