How now shall we habitual detractors of "docudrama" justify our indecent enthusiasm -- and Hollywood's -- for a movie that takes gross liberties with Mozart's life and death, and still grosser ones with the character of his rival Salieri?

Well, what is permitted to Jove is not permitted to mere beasts. "Amadeus" is so lordly a prank with history as to render its distortions morally irrelevant. It recalls the liberating view of Emerson, that foolish consistencies are mere hobgoblins.

One imagines that neither writer Peter Shaffer nor director Milos Forman would have wasted valuable time fretting over such issues, any more than Shakespeare chewed his nails in anguish as he reshaped the Richard III or Macbeth or Julius Ceasar he found in the pages of Holinshed or Plutarch.

Drama selects its raw materials with shameless arbitrariness, having an eye to epitome rather than literalism. Its task is to play variations on universal themes; and that theme in "Amadeus" is the absoluteness of art, and indeed in this instance the most absolute of arts, music.

By portraying Mozart, with passable justice, as a foul-mouthed, sensual but endearing 18th-century punk, and his rival Salieri as a prig, "Amadeus" makes a paradoxical point: The greatest art often springs from improbable sources (roses from dunghills) and is its own justification.

For years after Mozart's tragically early death, rumors buzzed about Vienna that Salieri, court composer to the Emperor Joseph II, had poisoned him. Shaffer isn't the first to exploit the story: Pushkin and Rimsky-Korsakov based an opera on it, "Mozart and Salieri," 87 years ago.

In Shaffer's retelling, Salieri is a competent professional musician who, in a twist on the Faust legend, has bargained his soul for musical inspiration. He promises to be a good boy -- as the world estimates good boys -- if only God will make him His instrument. God grants the favor, but only up to a point: the point that divides professional competence from genius.

Encountering the impish genius Mozart, Salieri finds God's fickleness and favoritism hard to swallow. Indeed, for the conventionally moral, the dunghill- rose connection is always a painful reminder that man's ways and whims aren't invariably God's.

Having unblinkingly faced that truth, "Amadeus" faces another, minor by comparison but dramatically useful: that great art is frequently at variance with academic convention.

In "Amadeus," academic opinion is embodied in several amiable fuddy- duddies around the court. (One of the story's strengths is the humanity it accords to all.) These arbiters of taste have the upper hand. They are shown giving the inventive Mozart no end of grief over such trifling issues as the "morality" of setting an opera in a brothel, over the mixing of ballet and opera; over the appropriate libretto language, whether Italian or German.

Whether or not any such tyranny of musical convention thwarted Mozart, it is as central to the story of art's absolute license as is Salieri's soured bargain with God. Academic rigidity is shown driving Mozart to folk opera, to "vulgar" audiences and tastes, as the background for his imperishable "Magic Flute."

"Amadeus" is a brilliant yarn, a powerful fable, compounded of truth, half-truth, harmless invention and dubious historical nonsense. Indeed, the fictitious Antonio Salieri may live longer than the historical one, yet the film and play have done the latter some service: Orchestras and classical-music stations are reviving his music.

As nearly as old medical puzzles may be solved by inference from dim evidence, it seems likely that Mozart died young of Bright's disease (which strikes the kidneys), not of poison -- and certainly not of weariness or fright induced by Salieri dressed as the ghost of his demanding father and pushing him to finish the "Requiem."

"Amadeus," then, pretends to be nothing other than what it is -- an exalted tale woven from historical scraps that makes enduring points about God, man and music. Makes them so well, in fact, that its key thematic point becomes its own excuse for existing: If you're good enough you can rewrite the conventions.

Even the Motion Picture Academy got that point.