THOSE OF US who are not entrepreneurs keep throwing out ideas from which entrepreneurs then make money. A columnist in Britain once invented a mythical organization called Rent-A-Crowd, from which one was supposed to be able to hire people to demonstrate against the bomb or abortion or whatever. Much to his amazement, and a little to his chagrin, an entrepreneur then created an actual company which offered just such a service indiscriminately to causes of the left or the right.

If I were an entrepreneur now, I would put my money into hats. Hats are coming back. For women, and for men. Big hats, and little hats. In 18 months, give a week or two, we will all be wearing hats.

My evidence is only that of a journalist who must, as an editor once said to me, work mainly by osmosis. "He absorbs his information largely through his pores." A few months ago, I began to hear all kinds of people, male and female, talking wistfully about hats. I found this so interesting that I asked others if they would like hats to come back. With two exceptions from crotchety men, the verdict has been unanimous. What is more, everyone has talked enthusiastically about hats, describing a hat they had once worn, or one they would now like. They make it seem as if hats have biographies.

Hats are gracious, of course, and they are attractive and, as many people have said, they are simply fun. But they are also more. There is no other article of clothing which we can use so expressively. One can look up from under it, or tip it to the back of one's head; pull the brim down, or curl it up, wear it jauntily at an angle, or push it firmly over one's eyes. It can be a come-on or a put-off, without a word having to be said.

It emphasizes the eyes, and beneath them the mouth, becoming a frame for the face, lifting our gaze to where character may best be seen, and holding our attention there. We say that moods "play" across our faces. A hat is a weapon of "play"; no tie or scarf or jewelry is so versatile.

Why did hats go out of fashion in the past two decades? I do not believe that John Kennedy's example was as important as is often suggested. There are fashions that owe something to personal influence, but they are usually short-lived. Nehru jackets had only brief lives. But the disappearance of the hat -- an item of dress that until the 1960s had been customary in our civilization --was clearly an event that had deeper roots, and its return will be a response to changes that are just as deep.

The most common explanation of the disappearance of the hat is that it is difficult to get in and out of cars with a hat on one's head. Perhaps there is something to this -- the spacious London taxi may partly account for the fact that hats are still worn there more than in other cities -- but such explanations always seem to be more like excuses. Obviously, if one really wanted to wear a hat, no inconvenience would deter; and anyone can move graciously in a hat even in the most confined space. Women with the widest of hats can sit elegantly in a Volkswagen.

IF WE ARE to understand it, we need to stick to the fact that a hat is unlike any other article of dress. It is a thing of gesture, with which we may express and even make a moment. Think of the squire in the Middle Ages, sinking to one knee before his lady, sweeping his cap to the ground in an act of surrender but not submission. without a hat, could his gesture have been so gracious and discriminating, or half so eloquent?

But think also of the old "pols" in their brown derbies, like Al Smith, their thumbs in their vest pockets. (And if the vest can return, why cannot the hat?) As they sat in their saloons or their smoke-filled rooms, with their hats on indoors, they could make a joint merely by tipping them to the backs of their heads. Simply with their hats, they could say: "No deal."

Whenever Disraeli was under severe attack in the House of Commons, he just slumped further and further down on the front bench and pulled his hat further and further over his eyes. Any attack will be blunted if it has to be addressed to the brim of a top hat. But equally, such a gesture is preferable to a scowl on the face. The hat makes a point without words that sting.

Franklin Roosevelt did not have only his cigarette holder and his jutting jaw. He also had a hat, and he would take it off and wave it to us. Even when he was old and sick in 1944, he drove through four boroughs of New York in pouring rain, doffed his hat and waved it. It was a much more friendly gesture than the raised arm of the Nazis or the clenched fist of the Communists or even the arms of Richard Nixon held above his head.

When hats were still worn in movies, a man and a woman would return to one or the other's home, and the woman would sweep off her hat, or the man flick his across the room, as if it was a frisbee. They were gestures, as though to say that the play was over, the play that they had enjoyed, and that they were now alone and open, private and at home, to each other. There was gallantry and graciousness, and an eloquence that spoke more than words.

But hats are not only things of gesture, expressions of a mood or of a moment. They are ways in which we can express sides of our personalities which we do not normally express. All of us to some extent become who we are by selecting from the many other things that we could have been. But these hidden parts of our personalities are still there, and a hat is a way of expressing them exactly as they need to be expressed: in play.

Myrna Loy or Rosalind Russell were not the same women when they wore sweeping, wide-brimmed hats as when they wore sweeping, wide-brimmed hats as when they had little pieces of nonsense perched on their heads. The first 20 minutes of "Mrs. Miniver" were occupied by her purchase of a frivolous but expensive hat, and it is the frivolity that paradoxically, is important. The playfulness, even the exhibitionism, is a display of things we need to express.

I remember few more pleasurable days in my life than the morning that I once spent with the wives of two friends as they tried on every hat in Harrod's in London; and Harrod's is a garden of hats. For two hours, I leaned against the counter as they put on and took off every piece of finery and nonsense in the place. They were as free and wild as ponies, every side of their personalities given expression, until at last they swept out with a "We're sorry, but none seem to suit us."

Men can use hats in the same way. Out on an errand the other day, I watched an elderly man boasting of his panama which he said his daughter had bought for him in Guatemala. An elderly man in a panama is spry. He might be spry without it, but not with such effect. Can one think of Maurice Chevalier without his boater, as he sang "Thank Heavens for Little Girls?" A boater to twirl, a panama to tip, "do something for us," as more than one person has put it.

BUT IN THE END, the need for a hat can be brought down to one consideration. It gives the time and the opportunity for courtship, not only between the sexes, although most obviously so, but in all our relationships. Even the most mundane of our relationships ought to have an element of courtship: of approach, of tentativeness, of inquiry. A hat enables us to say, "However well you know me, you don't know the whole of me; and you need to take the trouble to know me today, for I may be different from yesterday." It is not so much that it makes our relationships more formal as it makes them more spacious, it gives the opportunity for hesitancy and curiosity, for reserve as well as spontaneity.

Hats are the opposite of the creed of the last decade: of letting everything "hang out." They are a request to be allowed to be sometimes private and withdrawn even in the most direct or intimate of relationships. They are a way of saying that not everything can be told at once or face-to-face, that occasionally some hesitancy is needed.

We have grown to think that, the more outspoken we are, the more truthful we are being. But this is a falsehood, and we are at last beginning to see through it. A hat may be a frame, but it is also a sanctuary, from which we can insist that, in order to reveal, it is sometimes necessary to conceal; that those who are most immediately and most insistently "open" are often those who never really are open; that, if someone wishes to know one, he or she must practice the ways of courtship, not occasionally but regularly.

So let us wear our hats, learn again how to doff them, how to sweep them from our faces, how to retreat behind them; and let Danbury, Conn., return to its proper business, and reap the profit.