Let's face it; unformation is funformation. There is something perversely satisfying about learning things one has no earthyly need to know. And if television supplies anything in abundance, it's that. Not a chocolate sundae; just the whipped cream and the cherry.

So why debate whether "Tom Snyder's Celebrity Spotlight," yet another hour of chi-chi chi-chat from the starzy set, serves any worthwhile purpose? Why, if that were the criterion for television programming, the set would be dark 150 hours a week. The fact remains that Snyder's show -- the second in a series airing tonight at 10 on Channel 4 -- does as classy and vital a job as possible at accomplishing nothing.

The program, featuring talks with Cher, Jack Lemmon, Chevy Chase and Loni Anderson, has a charm peculiar to kindred fluff like trash-sports, fastfood, non-news, People magazine and Mr. Bill. Tom Snyder take so readily to television that you get the feeling he zips it up and sleeps in it at night. t

On the first in this series of occasional specials. Snyder came off as a hit too worried that a slightly cheeky question to one of his guests might mean he would never get invited over to the star's house for dinner. On tonight's edition, he is less of a puppy dog and more of a Doberman pinscher.

To judge by the standard set by the very inimitable Barbara Walters in her interview shows on ABC, Snyder's hour still ranks as insufficiently embarrassing, much the way the recent TV movie "Scruples" was insufficiently disgusting. Perhaps Snyder is out to prove that this sort of thing can be done with dignity -- but that may be like turning professional hockey into a gentlemanly tiff.

Certainly, though, producer Andrew Friendly and director George Paul have given Snyder fancy and yet tasteful trappings; this is probably the best looking and least cheesy program of its kind ever done.

And now for the real hot poop. Cher, wearing earrings that look like barracudas, says, "I'm very shy," concedes she has had a "drug problem," recalls the first time ex-husband Sonny saw her in a bathing suit, complains that she's too famous to do what she wants, and makes the understatement of a lifetime: "I'm not the greatest singer in the world."

Shots of Cher recording in an L.A. studio confirm that her vocalizing continues to sound like the cries for help of a trapped miner.

Jack Lemon is fairly eloquent on the subject of what an actor -- a real actor -- does for an audience and for himself. Lemmon says nothing that could lower the opinion of anyone who admires and respects him.

Then there is the opposite extreme, Chevy Chase, a model of arrogance, solipisism and ingratitude. "Saturday Night Live," which catapulted him into a number of spotlights, is really not very good anymore,, Chase says, and he rarely watches it. He denigrates the work of former co-star John Belushi, a more gifted comic actor than Chase will never be, and claims that "Foul Play," a disreputable comedy in which Chase appeared, was "a bigger hit" for him than "Animal House" was for Belushi.

The contention is preposterous.

On the other hand, it might be refreshing to find that Chase is so unguarded and unpackaged as to be so ungracious. On the other hand, he seems clearly to be a cad as well as a ham. But of all the incongruous things, he does have some advice for Sen. Edward Kennedy that sounds absolutely correct.

Loni Anderson talks about her original hair color, her religious upbringing, and how she gets "hugged by grandmothers" at supermarkets for the way she plays the resident bombshell on "WKRP in Cincinnati." George Paul's close-ups of her are sensational.

Celebrities, celebrities! Will there be enough celebrities for the '80s? Will that factory in El Segundo that manufactures them be able to keep up with the demand? Will Merv and Mike and Johnny and Tom have an ample supply at all times, so that we can learn new things we never needed to know? It follows as the night the day that there will be plenty of celebrities because celebrities are created by being put on television.

It all starts with a role in a daytime or prime-time program or even, these days, a commercial. Then you graduate to the game shows -- starting in the lower right-hand corner of "The Hollwood Squares," then over to Merv's furniture, and on to Johnny's couch. If all goes well, Tom Snyder or Barbara Walters will eventually certify you a celebrity, or "60 Minutes" will either label you an institution or indict you into the hall of infamy.

One could deplore it all easily enough, but it's too late for that, and Snyder's brisk, respectable and attractive show tonight is a reminder that idle chatter from the glitzocracy can provide more surpise and remotely human interest than the typical prime-time Hollywood doddle. In television, unformation is still a better deal than untertainment.