THERE HAVE BEEN TIMES -- usually in a rush of gratitude -- when I've thought human experience might be incomprehensible, if not intolerable, without fiction to tell us what we're doing and how we feel.

We see ourselves poorly, without mirrors on our hidden circuitry. Friends, remain personal mysteries. Sharing attitudes, no analyzing motives, keeps bonds tied. And love, as Antoine de Saint-Exupery told us, consists not in gazing into one another's souls, but in looking together in the same direction. Authenticating human drive and emotion is the province of art and science -- odd partners using the same tactics of observation and control. But only fiction gives us access to the deepest confusions of human character because only fiction creates and fully controls its characters. Thus, fiction may carry more truth than reality. I closed Shirley Hazzard's luminous novel grateful for as moment of ordered life.

Such moods cannot last, of course. Life is not a novel. Imagination is only a temporary refuge. But I know as surely as tears are wet that through fiction like The Transit of Venus we see into character and motive, through the precision of art, as we cannot see them in fragmentary actual experience. During the passage of The Transit of Venus we live other lives to discover more of our own.

Shirley Hazzard's novel unfolds in rural England, the Chelsea district of London, Japan, the Algarve of Portugal, New York City, Chile and Stockholm. Therefore it evokes place as a necessary condition of its style and the circumstances of its six pivotal characters. It begins at the time of the Korean War and ends with Detente. Therefore it ponders Europe drifting toward anarchy, Soviet tanks grinding into Hungary and Czechoslovakia, political murder in Latin America and soical assassination in the United States, and a relentless catastrophe laying waste Southeast Asia. Shirley Hazzard worked 10 years in the United Nations Secratariat, and left to write her critique, Defeat of an Ideal (1973). She still laments internationalism's impotence against the truncheon of dictatorship.

But the larger world of ideological competition and social hunger serves Hazzard like her ice-water lakes in Sweden, Kleenex-box buildings in New York or lacerated countryside in Britain. She is a projectionist. She focuses her characters into place. They and their climates, terrains and social contracts become one.

The essence of her narrative is that life is a sequence of chance encounters acquiring meaning chiefly through human commitment to a purpose, a belief, a passion. Her primary characters are two women, Grace and Caro, orphaned in Australia, blooming in England, and making their different ways into middle age through jobs, marriage, children, love affairs, disappointment, money, death.

Caro takes risks. Grace plays it safe. Consequently Caro gets more of Hazzard's attention. There's more to learn from her.

For 30 years Caro and Ted Tice, a radar astronomer, carry on an itinerant friendship. Ted loves Caro from the time they share rooms at the home of Sefton Thrale, grand old man of British astronomy, whose civil-servant son, Christian, is engaged to Grace Bell. Rebuffed, Ted follows Caro through her humiliating, sky rocketing, "limbo of sexual love" with Paul Ivory, a fashionable playright who marries an aristocrat for safety and who exploits others for pleasure.

Desperate, near nervous breakdown, Caro meets and marries an American international philanthropist-libertarian, Adam Vail. Ted Tice recedes into a marriage for practicality. After Vail's death Caro is finally forced to confront the evil "overwhelming self in Paul . . . his very sins were impressive to him." Paul Ivory once willed a man to death. He had taken up with Caro as an act of revenge on Ted Tice. At the close of the novel Caro and Ted meet in Stockholm. Both have changed. But Ted still sees Venus in Caro, and she has knowledge, if not wisdom. They reach for a future together. It cannot happen. In two modest sentences earlier in the novel Hazzard has foretold a calamity. Ted and Caro are destroyed.

Shirley Hazzard doesn't argue that others in her novel -- Grace and Christian, Ted's wife Margaret, Paul Ivory's poet father Rex, Christian's mother Charmian -- live or love more wisely than Caro or Ted. Her purpose is to reveal them in the act of living and to make their pleasure, anguish and confusion rise out of their personalities as they respond to change. Caro and Ted live at a swifter pace. But all of The Transit of Venus is human movement, and seen from near the highest level art achieves.

Shirley Hazzard's novel seems to me almost without flaw. Aphoristic and iridescent, her language turns paragraphs into events. Her perceptions of gesture, voice, attitude bespeak an omniscient understand of human personality. The story she tells it, for the most part, so usual as to sound irrelevant. What she brings to it is virtually everything that story alone cannot tell about human lives.