HUMAN BEINGS, WE ARE TOLD, make use of only a small portion of their brainpower, and there is no telling what we could do if we could only operate at full strength. I'm sure all of this is true, but recognizing my limits, I have tried to concentrate only on things that I really need to know, and not clutter my mind with trivia or things it could never master anyway. Whole areas of math and science, for example, I've left to others. Likewise for such things as the internal workings of automobiles and the rules for cricket.

And there are certain things about Washington that I've happily left to others to chronicle or, at least, worry over. One of these has been Washington's "old society," called either cave dwellers or cliff dwellers or cliffhangers or something like that. I long ago nominated Washington's various private clubs for membership in that same category. Thus, I have never distinguished very much between the Metropolitan Club, the Cosmos Club, and the Federal City Club and the University Club and the F Street Club and the Touchdown Club, although I'm sure each and every one would be horrified to be lumped together with the others. The only club I've ever really worried about is our neighborhood swimming club, which is, if you must know, not a club at all but a recreation association which excludes you only if the membership list is full or if you have not paid your annual dues. Near, it is. Exclusive, it is not.

My decision not to care about these various aforementioned clubs was reached lightly, and I have never regretted it for a day. On occasion, however, one of these terribly soigne clubs pops into the news for doing something so bizarre or so outrageous that even those of us who don't give a hoot about them the rest of the year have to get interested. Who, for example, could forget the, ahem, 'incident' at Congressional Country Club in which a perfectly respectable physician -- you don't get into Congressional unless you're perfectly respectable -- up and killed a goose on the golf course?

It had been awhile, though, since any of the clubs had done anything equally entertaining for Washington newspaper readers but, thank heavens, the Cosmos Club is the one that admits you on the basis of accomplishment and achievement in the arts, sciences, public service and genetic selection.

Some years ago the Cosmos Club made the news by not admitting Carl Rowan, the distinguished journalist who was then serving as deputy assistant secretary of state. His achievements in the arts and public service categories were wiped out, however, by his lack of judgment in the genetic selection category. Rowan picked the wrong genes and was born -- you guessed it -- black.

The Cosmos Club has subsequentlly admitted blacks as members and women have been allowed in as guests, but now -- wouldn't you know it -- a group of radicals in the club want to change the rules and admit women to membership. This bold stroke for mankind has not only set off a steaming controversy within the membership, it has set each and every one of the club's 16 past presidents on their collective ear. So much so, in fact, that they have written the members to alert them to the danger and to let them know that they, the Past Presidents United to Preserve the Cosmos Club, are at the ramparts. And let me tell you that while they are claiming to preserve one of the great "gentlemen's clubs of the world," there is nothing gentlemanly about that letter. They are accusing the radicals of inaccuracies and irrelevancy, of fuzzy thinking, of working from within to destroy, of being threatening and of trying to transform the prestigious institution into a mere luncheon group.

They say that if the club goes ahead and admits women -- it has twice refused to do so -- it would mean costly renovations to the clubhouse and "epic" confusion among male and female guests and members. And, to top it off, it would mean a "breaking of faith with the Founders and the many generations of members who have loved their men's club, who have supported it with devotion and unremunerated laabor and have bequeathed money and other treasures." The presidents conclude that the subversive elements, also known as "Concerned Members," "have every right to form the kind of club they espoused; but it is our position that they should make the effort outside the confines of the Cosmos Club." So there.

Well, the Concerned Members -- and I might tell you that I recognized a lot more of their names, (such as Arthur Goldberg, Alan K. Campbell, John W. Gardner, Patrick Hayes), than the names of the past presidents -- have sent a questionnaire polling the membership on this issue, and while some 700 answers came in within four days, no one yet knows the verdict, since the club has not consented to monitor the tabulation. So we will all just have to control ourselves and wait patiently for the outcome.

I, of course, am absolutely on pins and needles over the whole thing, as I'm sure the rest of Washington is. But if there is anyone out there who, perish the thought, could care less, he should at least give a small thanks for the Cosmos Controversy. It's certainly a lot more entertaining and a lot less worrisome than waiting around to see who is going to be named to the Reagan cabinet.