It is said that Madame Geoffrin, the formidable grande dame of 18th-century Parisian culture, once refused to admit to her salon a well-known political economist. He had previously frequented her famous international gatherings, but suddenly found himself shut out. Why? ''His society is insupportable,'' she wrote to a friend. ''He states too many facts, makes assertions which are undeniable, and is always in the right.''
Poor fellow! Two centuries later, we understand his problem all too well. It seems he was behaving like a computerized data base. Packed full of technical detail, he could neither see beyond it to universal principles nor relate it to the broad sweep of human conversation. Instead, he overflowed with answers to questions nobody had asked. He was a pedant - unduly emphasizing minutiae, telling more than anyone cared to know on any given occasion.
In this age of data gathering and information dissemination, his example is instructive. For, like Madame Geoffrin's guests, we risk being overwhelmed by details. Consider that:
* This year over 50,000 books will be published in the United States - up from 18,000 in 1961.
* There are 12,010 magazines listed in this year's Ayer Directory of Publications - up from 10,688 just a year ago.
* Computer specialists estimate that there are now more than 1,700 data bases available worldwide to computer-equipped homes and offices.
The world, in other words, is wallowing in detail - ''drowning in information , but starved for knowledge,'' as social forecaster John Naisbitt observes in his best-selling book, ''Megatrends.'' At the touch of a keyboard these days we can learn more than we can possibly absorb on any subject. And while it is true that attention to detail is a hallmark of professional excellence, it is equally true that an overload of undigested facts is a sure recipe for mental gridlock.
The problem is one of excess. Not restricted to the information industry, it seems sadly reflective of the times. We are beset on all sides by excess - sometimes immoderate in our diets, often unexercised (or over-exercised) of body , prone to exceed speed limits, and extravagant in our use of wealth. Quite properly, we worry about it: Of the 15 books on last week's New York Times best-seller list, five had to do with diet and exercise, and several others with wealth.
How do we deal with such excessiveness? What's missing? A simple thing, really: the capacity to be selective.
To her credit, Madame Geoffrin knew the importance of making proper selections. She knew that the real question was not ''Where can I find out more?'' but ''What do I really want to know?'' She may have sensed that the answer to lack was not glut - and that excess, perhaps more than scarcity, needs careful management. She had something our age needs: the courage to choose, from a surfeit of offerings, the most useful.
That's the challenge facing the news media nowadays. On the surface, we debate whether to provide lots of news in brief or a few stories in depth.The fact is, however, that both courses require a tremendous winnowing of the supply of information. And the supply is growing. These days, the most valuable talent is not the ability to tell all. It is the capacity to winnow intelligently - to focus sharply on the most worthwhile ideas.
It is in that context, then, that the decision of NBC television correspondent Judy Woodruff to move to PBS's newly expanded ''MacNeil-Lehrer Newshour'' is such an interesting one. Tired of what she calls ''the quick narration, standing correspondent, and three-minute interview on the morning news shows,'' she told the Monitor's Arthur Unger recently that she looked forward to satisfying ''the craving out there on the part of a lot of people for news in perspective, for news with depth, rather than just skimming the surface.''
''News in perspective.'' That, it seems, requires the highest order of selectivity - the willingness to concentrate on a few things without stating so many facts that the reader is overwhelmed.If she and her colleagues at PBS can prove the value of such selectivity, they just might become the Mesdames Geoffrins our age so needs.