From Neil Simon, a fairy-tale farce?

Fools, Staring John Rubenstein. Comedy by Neil Simon. Directed by Mike Nichols. Once upon a time there was a stage and screen playwright named Neil Simon. So prolific was he that it sometimes seemed there must be several Simons: one to write comedies like "California Suite" which he would later adapt for the screen , another to create original movie scripts like "Seems Like Old Times," another to write the books for musicals like "They're Playing Our song."

The hand of yet another Simon could be detected in such offbeat oddities as "God's Favorite" (drawn from Job) and "The Good Doctor" (drawn from Chekhov). This was no simple Simon.

In "Fools," at the Eugnene O'Neill Theater, the protean Mr. Simon reveals a new and slightly different comic facet: a bent for fairy-tale farce, yokel jocosity, and rustic morality play.One detects the far-flung influences of Lewis Carroll and Sholom Aleichem, not to mention the Marx Brothers and W. S. Gilbert.

The fairy tale for young and old tells how Leon Tolchinsky (John Rubinstein), a highly qualified and even more highly motivated young teacher, comes to take up his post in the long-ago Ukrainian village of Kulyenchikov. Unbeknownst to Leon, the village is under a curse of stupidity. Unless he can instill the rudiments of education in the local doctor's dumb but beautiful daughter (Pamela Reed), the curse will remain. Like all good fairy tales, "Fools" boasts a villain in the person of a wicked count (Richard B. Shull), whose family originated the curse.

Under Mike Nichol's direction, "Fools" is acted with intense, make-believe sincerity by the agile and eloquent Mr. Rubinstein and his colleagues. Miss Reed personfies wide-eyed innocence as the eager-to-learn heroine. The comic stalwarts of the fantasy include Gerald Hiken as a lost-sheep shepherd, Harold Gould and Mary Louise Wilson as the heroine's daffy parents, and Florence Stanley as a village vendor who mistakes flowers for fish and milks her cow upside down because the cream comes to the top.

In this kind of deliberate looniness, it is not always easy to tell whether some of the feebler plot ploys are part of the comic design or merely attempts on Mr. Simon's art to bail himself out of what is basically a one-joke situation. In any case, the preview audience on the night of my visit to Kulyenchikov not only tolerated "Fools" gladly but greeted the harmless, sometimes frantic antics with roars of appreciative laughter. They also went home with a moral that might run something like this: Ignorance isn't bliss, and it's folly to be stupid.

John Lea Beatty has provided the production with the kind of slightly teetering storybook scenery that belongs in topsyturvydom. Patricia Zipprodt designed the long-ago rustic costues and Tharon Musser has thrown helpful light on the triumph of academics. Besides playing the man who rescued Kulyenchikov from stupidity, Mr. Rubinstein composed some lively incidental folk music in the Russian manner.