Clare Boothe Luce has not so much lived her life as written it as an epigram. She was born with the gift of intelligence and the curse of seeing the world as ludicrous.

"Without a tragic view of life, you can't find it as funny as I do," she said last night. "The difference between a pessimist and an optimist is that the pessimist is better informed."

Last night, five weeks after her 80th birthday, the wit and the beauty were holding up well at a verbal "Self-Portrait at the National Portrait Gallery." Those of the about 300 guests who came expecting a drawing room dialogue from the famous playwright of "The Women" were not disappointed.

Neither were those who came to hear the Republican politician and diplomat who was a member of Congress from Connecticut and an ambassador to Rome. Today she is a consultant to the National Security Council, a member of the Foreign Intelligence Advisory Board, and an amazing combination of a grande dame and an enfant terrible.

Paying tribute to her past and her present was an appreciative group that included three CIA directors, two past and one present--William Colby, Richard Helms and William Casey--the Librarian of Congress Daniel Boorstin, the Architect of the Capitol George White, former Nixon secretary Rosemary Woods and Luce biographer Sylvia Morris.

In fine form, shimmering with sequins, wearing enough pearls to decimate a bed of oysters, Luce ranged with Marc Pachter, the National Portrait Gallery's historian, over her various starring roles with words about the costars and the bit players in the road company of her life. She spoke much about the cheers and a bit about the boos.

She neatly dug a grave for the long-standing rumor that George Kaufman had written parts of "The Women," her biggest hit. "He used to say, 'Do you think that if I'd written a play that made $3 million, I would've put her name on it?' "

When she was in Congress, she said, "someone was always saying that my husband Henry Luce, owner of Time-Life had his staffers write my speeches for me. But it all balanced out, sometimes people said I wrote his editorials for him."

Listening to her last night, it is doubtful that anyone would dare write anything for her. Looking at Secretary of Defense Caspar Weinberger, sitting on a front seat at the discussion, she gave a mild example of the sort of thing that made many enemies in her career. She chastised Weinberger for popularizing the phrase "build-down."

"The secretary is a great patriot," she said, "but he would certainly do the country a favor if he would get rid of 'build-down.' "

She said she learned at a party recently that former senator William Fulbright had never forgiven her for the time she corrected his use of imply and infer. And she told about the congressman who told one of her verbal victims not to mind her because "her real vocation is writing. She attaches meaning to the use of words."

Luce told of a time she met her match. "When 'The Women' was a success in London, I was brave enough to ask Sylvia Astor to introduce me to George Bernard Shaw. I wrote out in my mind what I was going to say."

But when she was shown into Shaw's study, he ignored her for so long she forgot her speech. "I just blurted out, 'Mr. Shaw, if it weren't for you, I wouldn't be here . . .' He looked at me and said, 'And what is your mother's name?' "

Pachter asked Luce which of her many roles she preferred. She said the most wonderful was to be mother to her daughter, who was killed in a car accident at 19. Luce said she mourned the grandchildren she might have had.

And in a characteristic shift, from dark to light, she went on to say she was proudest of learning scuba diving after she was 50.

"I took a certain pride in that President Eisenhower gave me 14 missions to accomplish as ambassador to Italy. And I accomplished 15--I persuaded Italy and Yugoslavia to settle their territorial dispute. I believe it is the only border disagreement since World War II solved short of war."

Luce admitted that her first ambition was to be a playwright despite her subsequent diplomatic career. In conversation after the formal dialogue, she said she has a play "gestating. But you know the kind of life we lead often acts as an abortion to the creative impulse."

It is said that no woman can be too thin or too rich. Last night, it seemed that Luce, who is thin and rich, could have ruled the world--if she had not also been too beautiful and too witty.