"Tragedy of a Ridiculous Man," now playing at the K-B Janus 3, may be useful as a standard of bafflement in contemporary moviegoing. There's no point in trying to make sense of the inexplicable, exasperating plot, which purports to observe the reactions of a self-made businessman, played by Ugo Tognazzi, whose son is kidnaped for ransom. Director Bernardo Bertolucci airily dismisses the mystery at the fadeout, declining to explain anything as matter-of-fact as who kidnaped the son, what happened to him and how he happens to return. The premise seems to interest Bertolucci only as a pretext for abusing the Tognazzi character, who entertains the idea of refinancing his business with the ransom money after he's led to believe that his son may have been murdered in captivity.

At best, one could surmise that Bertolucci was groping with a theme of generational antagonism or moral corruption, but the struggle is expressed in a form too tentative and symbolic to justify attention.

Watching "Ridiculous," one is acutely conscious of Bertolucci's reliance on the arbitrary. Indeed, it's led him up an esthetic dead end. The "spontaneous" characteristics in a Bertolucci scene have become predictable and ineffective--cliche's. They may remain his cliche's, the bizarre or overemotional flourishes that have come to be associated with Bertolucci, but they've ceased to express anything fresh or fascinating about the characters. Someone has a breakdown. Someone goes into a dance. A man and woman grope at each other in sudden lust. Someone gets slapped. It's all there, degenerating into terminal shtick.

For old time's sake, you may want to see Anouk Aimee, who turns up as the suspiciously busy wife, avid to liquidate her husband's assets. As a documentary sidelight, the husband's business--cheese manufacture in Parma--is good for a few interesting glimpses of how things are made and organized in a clean, efficient factory. The oddly spooky young actress, Laura Morante, who plays the factory worker who claims to be the kidnaped son's girlfriend, may be recommended as an erotic curiosity. Moreover, she and Tognazzi are involved in one of Bertolucci's goofiest improvisations ever, a scene that resembles nothing so much as a Foto Funnie from National Lampoon. The camera discovers them in a mood of brooding contemplation. Morante breaks the silence by declaring, "You make me feel uneasy and p---ed off." Tognazzi stares at her. Impulsively, she lifts her sweater over her head, revealing a centerfold set of breasts. She glares at Tognazzi, who responds by exclaiming, "God, what t--s!" Bertolucci lingers over this magical moment of revelation as Morante continues to fume with her breasts on display and Tognazzi continues to stare in admiration. End of scene. Ridiculous is putting it mildly.