His mind has been supplied with a fund of simplistic generalizations about the world, phrased in terms of the garden where he has worked all his adult life. But because he presents himself as a man of good breeding (he walks and talks like the wealthy older man whose house he lived in, and wears the man's tailored suits) his simplicity is mistaken for profundity, and soon he is advising presidents and befriending millionaires.

The man's name is Chance. We gather he has lived all of his life inside the townhouse and walled garden of a rich recluse (perhaps he is his son). He knows what he needs to know for his daily routine: Where his bedroom and bathroom are, and how to tend the plants of the garden. His meals are produced by Louise, the cook. The movie provides no diagnosis of his condition. He is able to respond to given cues, and can, within limits, adapt and learn.

Early in the film he introduces himself as "Chance . . . the gardener,'' and is misunderstood as having said "Chauncey Gardener.'' Just the sort of WASP name that matches his clothing and demeanor, and soon he is telling the President: "Spring, summer, autumn, winter . . . then spring again.'' Indeed.

Chance is played by Peter Sellers, an actor who once told me he had "absolutely no personality at all. I am a chameleon. When I am not playing a role, I am nobody.'' Of course, he thought himself ideal for this role, which comes from a novel by Jerzy Kosinski. Sellers plays Chance as a man at peace with himself. When the old man dies, the household is broken up and Chance is evicted, there is a famous scene where he is confronted by possible muggers, and simply points a channel changer at them, and clicks. He is surprised when they do not go away.

Sellers plays Chance at exactly the same note for the entire film. He is detached, calm, secure in his own knowledge, unaware of his limitations. Through a series of happy chances, he is taken into the home of a dying millionaire named Benjamin Rand (Melvyn Douglas). The millionaire's wife Eve (Shirley MacLaine) establishes Chance in a guest suite, where he is happy to find a television (his most famous line is, "I like to watch.'')

Soon the rich man grows to treasure his reassuring friend. The family doctor (Richard Dysart) is perceptive, and begins to have doubts about Chance's authenticity, but silences himself when his patient says Chauncey "has made the thought of dying much easier.'' Chauncey is introduced by Ben to the president (Jack Warden), becomes an unofficial advisor, and soon is being interviewed on television, where his insights fit nicely into the limited space available for sound bites.