"Schematic" is among the putdowns most favored by film critics these days, but if TV critics used it they'd have to apply it to nine out of 10 shows on the air. Prime-time television entertainment consists largely of formulas, charts and veritable computer printouts.

The new entry in the Norman Lear confrontation comedy tradition, "In the Beginning," premiering on CBS (Channel 9) at 8:30 tonight, turns out to be Lear's flop "All's Fair" with the libby swinger of a reporter turned into a hip nun and the stuffy conservative columnist turned into a stuffy conservative priest. The seams show, the elements are elementary and the whole thing reeks of calculation.

Given the ritualistic limitations of the format - essentially it's the Wednesday Fights - the premeire script, by Jim Mulligan and Norman Steinberg, is a craftsmanlike job that scores a high quota of laughs. It is amusing but somehow fantastically uninteresting.

The chief combatants, Father James Cleary (McLean Stevenson) and Sister Agnes (Priscialla Lopez) - "Attila the Nun," he calls her - argue and bicker along the well-traveled liberal-conservative great divide. "The trouble with you is, you've o.d.'d on affluence," she tells him. "If she had her way, the 10 Commandments would be called the 10 Suggestions," he says of her.

Sis wants to open a "social service center in the poorest part of town" and Msgr. Benoit (the very agreeable Jack Dodson) wants Father Cleary to help run it, even though he complains, "I don't know the first thing about poverty" and offers the monsignor a sweet deal on a Cadillac Seville as a bribe to get him off the assignment.

The characters tend to be either too good or too bad to be true. Sister Agnes has her act so oppresively together andcomes off so perky and spunky that it's a bit of a drag. She even knows judo, and threatens a hoodlum at the sociial center with, "One false move and you'll be singing soprano."

Perhaps because the nun's dialogue is saltier than in traditional depictions, and because Father Cleary is portrayed as infinitely fallible, a certain air of controversy will spark interest in the series, but it's a pretty feeble spark. When Sister Agnes prophesies with Father Cleary that "we'll have our occasional disagreements," we know all too well just how occasional they will be - every Wednesday, same time, same station, same show.

'Vega$'

There are formulas for synthetic candy and there are formulas for chemical fertilizer, and perilously similar to the latter is the recipe that brings us "Vega$," dollar sign theirs, a new ABC action series premiering at 10 tonight on Channel 7.

Robert Urich stars as smirky Las Vegas private eye Dan Tanna, who, because of new TV violence limitations, tends to bark more than bite. "I'd love an excuse to take you apart," he tells an extortionist, and then, putting a gun to the man's left nostril, adds, "You're slime; I'll kill you and you'll seep right back into earth."

Tanna drives a nifty old red T-Bird, wears tight blue jeans, has unrestricted access to beautiful women, and corners crooks and creeps, as he did on the high-rated two-hour movie version of "Vega$" last spring, mainly by striding toward them (and the camera) somewhat in the manner of Dirty Harry.

An attempt is made to leaven all this with levity, and the premiere, which is mostly about a gorgeous blackmailed model, also has a running gag about a missing lion. Cute. The supporting cast includes not only Tony Curtis, who deserves to be reduced to this, but Will Sampson, the towering Indian of "One Flew Over the Cuckoo's Nest," who plays Tanna's stoical flunky - a sort of not-very-gabby Gabby Hayes. He does not deserve to be reduced to this.

"Vega$," though eminently worthless, is expected to be one of the hits of the new season. If not and it were to be canceled, it would seep right back into earth, wouldn't it?