Anthology of Alter Egos : CHANGING THE PAST <i> by Thomas Berger (Little, Brown: $18.95; 292 pp.; 0-316-09149-9) </i>

Literary culture and polite society are governed by many assumptions honored in theory but ignored in practice. One such would have it that hating people is as wrong as eating them. The civilized ideal is to comprehend all and then forgive; even so, polls show that a majority of people favor capital punishment.

Thomas Berger is a hater, or to put it more genteelly, a misanthrope. A misogynist too, for that matter, often of the street corner variety whose dirty jokes all spring from the same wishful premise: “There’s only one thing they want, and they can’t get enough of it.”

Certainly on the evidence of the female characters in his latest novel, “Changing the Past,” Berger’s estimate of the sexual mores and stratagems of womankind mirrors Lear’s: “Down from the waist they are Centaurs, though women all above.” (Act IV, Scene VI).

In the first and most extended of several such scenes, high-school freshman Jack Kellog finds it “simultaneously horrifying and thrilling” to be fondled by his Centaurette classmate Betty Jane Hopper, who “far from being the Sunday schoolgoer of . . . innocent assumption . . . was a shameless whore.”

But lechery is only one item on Berger’s bill of indictments against the human race, and when he is not cranking out ribald fancies of innocent males corrupted by female concupiscence, his invention and invective are both much livelier, and sometimes even deadly.

He is at his best when he imitates the summary narrative style of biography, rather than in extended dramatic scenes for which he lacks the marksman’s eye and craftsman’s patience of Tom Wolfe in his no less misanthropic but so much more persuasive “The Bonfire of the Vanities.” But at its own natural hastening pace, “Changing the Past” can carry the conviction and impact of a newspaper obit or one of the “true histories” of Daniel Defoe.

Formally, “Changing the Past” is a fantasy about a New York copy editor who is offered the opportunity to erase the life of tame probity he has been leading (a life recently darkened by the discovery that his only son is dying of AIDS) and to try on larger destinies for size.

He becomes, in turn, a real-estate tycoon, a stand-up comic, a famous novelist and a radio psychologist whose wife is elected President. Each of these alternate lives proves dissatisfying and, eventually, disastrous. Yes, Berger seems to be assuring his readers that “you may travel far and wide, mid pleasures and palaces, but finally there’s no face like your own.”

The notion is not original to Berger: J. M. Barrie handled it with memorable flair in his 1917 drama, “Dear Brutus.” In Berger’s handling, this fantastic premise is little more than a pretext for publishing three quite independent novelettes as a novel. The alternate lives of copy editor Hunsicker seem neither to spring from his character nor to illuminate it, and even in the way he shows Hunsicker experiencing his revised lives, Berger is inconsistent.

In his first new life, Hunsicker jumps into the skin of a contemporary (mid-’80s) millionaire skirt-chaser, spends a few hours riding around in his new identity but unable to grab hold of the steering wheel of his will. The next three incarnations are handled without any reference to the passenger-like Hunsicker and tell cradle-to-grave stories of the three different louts who have nothing in common but the same surname, Kellog, and a general tendency to make the worst of their opportunities.

So forget the frame, as Berger mostly does. The separate stories are enjoyable, especially the first, a vitriolic account of the rise and fall of a Mafia-sponsored nightclub comic, Jackie Kellog. He attains national celebrity when he’s taken under the wing of a Sinatra-like crooner, Tony Gamble, who offers him this advice on the art of stand-up comedy:

“Do what you been doin’, only nastier. Draw blood, you know? People love that. Be a good contrast for when I come on with the ballads. People like to laugh, and they like to cry. That’s what we do, kid, get the feelings out of them. You might say we’re kinda doctors.” He threw back his head and chortled. “Or whores!”

Berger’s own theory of humor is not much different from Gamble’s--jokes are weapons, and laughter the baying of a pack of predators. Berger knows whereof he speaks, since he is himself a skilled comedian and cruel satirist. One would expect, then, that he would do as thorough a job of demolition on the literary world in his account of the hapless novelist, John Kellog, but John is a much less ambitious target, a writer with little talent except for satisfying the insatiable sexual appetite of agents and editors.

His novels are romans a clef sopping with self-pity. As a character, he is less plausible than the comic Jackie, and as a target of satire, less representative. Berger’s story might have been satisfying if he had followed John’s practice of basing his inventions on real life. Venom is not effective against straw men.

The third Kellog is a bogus “doctor” purveying advice about sex on daytime radio. C. V., though briefest of the three, is best suited to Berger’s gift for rapid-fire narrative invention, since each of the callers to the talk show can sketch out his or her own brief outline for another Bergeresque comedy of terrors. Watching their woes mount to preposterous heights of woefulness is a little like looking over the author’s shoulder as he sketches out the plot of a novel.

Berger, like his comic and his talk-show host, is an improviser. He writes quick, clear, uncomplicated prose and spins out plots that have the ring of modern-day commedia del arte (which is probably the reason his novels “Little Big Man” and “Neighbors” translated so well into movies). One happy consequence is that Berger is prolific, with seven novels since 1980. A less happy consequence is that his performance is erratic. When he’s on a roll, he can be great fun, but when he’s not, he lacks the patience to patch out a lack of immediate inspiration with mere hard work. In “Changing the Past,” he’s on a roll no more than half the time, but half of Berger’s roll is not only better than none, it’s delicious.