cross-pollination

[L]ike people, ideas have social lives. They__e one way when they__e by themselves, and another when they__e surrounded by their peers. Crammed together, they grow more uncertain, more interesting, more surprising; they come out of themselves and grow more appealing, and funnier. You wouldn__ want all of intellectual life to be that social--we couldn__ make progress that way. But there__ a special atmosphere that develops whenever truly different ideas congregate, and, on the whole, it__ too rare.