When I was 13 years old I was chaperoned here and there, along with two sisters of about the same age, about the greater environs of London. My music teacher, whom I loved and still do, was by my side when I went to the counter of a little souvenir shop in Stratford-Upon-Avon and paid out three or four shillings for Shakespearean sundries I had picked out. An elderly lady took my money, withdrew from the display case a tiny one-square-inch edition of ''Romeo and Juliet'' and, smiling, gave it to me. A gift. I took the sixpence she had just before given me in change and deposited it in her hand: a reciprocal gift. Once outside, I received a kind but resonant rebuke from my music teacher. I had done an offensive thing, she instructed me. A gift is a gift, she told me. I must learn, she said, to accept gifts. They are profaned by any gesture of automatic reciprocity.

Many years later I read, in some biography or other of Abraham Lincoln, about an episode that had briefly stalled the receiving line at the White House with corporate embarrassment. A lady in the receiving line, after taking the president's hand in formal greeting, stuck forward with her left hand a huge bundle of long-stemmed roses, depositing them in Lincoln's hand. The president -- and the receiving line -- were immobilized. Abraham Lincoln smiled. And said, ''Are these really for me?''

''Yes,'' the guest replied, beaming.

''In that case,'' Lincoln said, ''I can think of nothing that would give me more pleasure than to present them to you.''

The flowers were returned; there were smiles all around; the lady took back her roses, smiled in turn, and the line moved on. That is a singular exception to my music teacher's injunction about the social sin of reciprocal gifts. Few people, in public life or private, have managed -- could manage -- such extemporaneous grace.

Many years went by. And then the other day I received on my trusty electronic MCI a message from a friend, a computer expert. He said that the retrieval system I had yearned for, which would permit me to locate individual book titles in my library via my computer, had been completed. He had worked on it (in the interstices of his busy schedule) for more than a month. ''It is yours,'' his message read, ''as a belated Christmas present.'' I flashed back on MCI (that is the only hazardous aspect of that wonderful system, the temptation to the on-the-spot reply) that I insisted that he send me a bill for professional services. One minute later, my mind traveling back to the little souvenir store at Stratford, in utter dejection I shed the grown-up equivalent of tears at my gaucherie.

The unrequited gift is, in Burke's phrase, one of the unbought graces of life. The effort there and then to repay scars the transaction: what is left is a fatally deglamorized event. The spontaneous or, for that matter, the long-contemplated appreciative gesture is X-rayed into desiccated atomic parts.

The universal offense, remarked by Ortega y Gasset as the mark of the masses in revolt, is that of the Westerner -- rich and poor -- who accepts, without any thought of any debt incurred, the patrimony we all enjoy, those of us who live in the free world. The numbing thought that we owe nothing to Plato and Aristotle, nothing to the prophets who wrote the Bible, nothing to the generations who fought for freedoms reified in the Bill of Rights: we are basket cases of ingratitude. We cannot hope to repay Socrates what he gave us, but to live lives without any sense of obligation to those who made those lives as tolerable as ours are -- the lack of gratitude to our parents who suffered to raise us, our teachers who labored to teach us, the scientists who prolonged our lives when our appendix burst -- is spiritually atrophying.

We cannot repay the gift of the Beatitudes. But the failure to recognize that we all owe a huge debt that can only be requited by our puny efforts to attempt, in our parlous way, to repay the gifts we inherit marks us as the masses in revolt: against our benefactions, our benefactors. To fail to feel gratitude, when walking through the Metropolitan Museum, or when listening to the music of J. S. Bach, isn't to profane the generosity of the little old lady behind the counter at Stratford-Upon-Avon, but to decline to express, however clumsily, our gratitude for the fruits of genius, for the generosity that gave us the lives we lead.