请教braid the cathedral如何解释？

乖乖

It is said that the mass media are the greatest organs for enlightenment that the world has yet seen; that in Britain, for instance, several million people see each issue of the current affairs program, Panorama. It is true that never in human history were so many people so often and so much exposed to so many intimations about societies, forms of life, attitudes other than those which obtain in their own local societies. This kind of exposure may well be a point of departure for acquiring certain important intellectual and imaginative qualities, width of judgment, a sense of the variety of possible attitudes. Yet in itself such exposure does not bring intellectual or imaginative development. It is no more than the masses of a stone which lies around in a quarry and which may, conceivably, go to the making of a cathedral. The mass media cannot braid the cathedral, and their way of showing the stones does not always prompt others to build. For the stones are presented within a self-contained and self-sufficient world in which, it is implied, simply to look at them, to observe-fleetingly-individually interesting points of difference between them, is sufficient in itself. 这是整段的原文，事实上，能查的单词都查了。但是整个都云里雾里的。不知道是什么意思。 是说什么呢？有高手能不能翻译下？