One thing can be said in defense of human error: At lest it's human. Human errors may be the only human things that machines will never be able to duplicate.

Maybe this is why there's something strangely comfortingly about goofs and bloopers on television. Even if they're machine-made, humans have to do the scrambling to restore order. And we're reminded at such times that there are indeed actual people lurking behind the prefab programming and the bionic laughter.

It's something much of television would let us forget.

When both the sound and the picture fail in television, the resulting void is called "dead air." We got a fairly heavy blast of that during the recent New York blackout that momentarily incapacitated the mighty networks and sent local stations into tizzies.

In Washington, WTOP comforted viewers with such pre-taped messages as, "Ladies and gentlemen, we are experiencing temporary difficulty with the audio-visual portion of our program." Portion? That's like saying, "Nothing is wrong, expect for everything."

Initially people amy have reacted with faint panic to this development. It was a little like being on the Metroliner to New York and, as is common, having the train stop with a thud just as you get within sighting distance of the city. Nobody tells you what went wrong or when, if ever, you'll again know the thrill of being trampled in Penn Station.

The least we expect of television is that it keep yammering away, however senselessly, because as a piece of furniture the average television set isn't all that scintillating. After a moment's silence or two, however, as if a loud smog had just lifted. So this is what life was like before television. Peace, it's wonderful!

Watching stations and networks slip and slide around in the effort to neutralize anything unforeseen can be more amusing than any plastic-perfect TV program. It was downright funny when, during the telecast of a horror movie on NBC Monday night, an ABC baseball game suddenly appeared. Someone had pushed the wrong button; let's find that someone and thank him for enlivening a pretty dull evening.

In the heyday of live television, of course, mistakes were more common and even more entertaining. Nearly everyone knows the story of the "corpse" who crawled away on-camera during the telecast of a live TV murder mystery.

A volunteer from the audience recruited for a live commercial on "Art Linkletter's House Party" once raved over the whiteness of the towels in front of her, testifying to the effectiveness of Rinso. Linkletter pointed out to her that the towels were in fact blue. "But," the woman blurted, "they told me to say 'white'."

Or there was the time Lon Chaney Jr. thought he had walked into the dress rehearsal for a live TV drama. He has script in hand and was reading the stage directions aloud, as well as the dialogue: "Now I walk over here to the telephone, then I pick it up and say -" Unfortunately for Lon, he was on the air. This was no dress rehearsal.

Give an old-time TV director a drink or two and you'll hear many such stories. They bring back a time when TV seemed closer to us as we watched it and closer to actual human experience. Videotape has destroyed much of that sense of sharing. That may help explain why critics who love TV have tended to overpraise the weekly live satire of "NBC's Saturday Night."

The program has hardly been a bedlam of fluffs, but there have been perilous moments. On a show hosted by Buck Henry last spring, the opening act called for a husky jock from the studio audience to jump on Henry as he stood on the stage. Unfortunately, nobody told the guy to jump off Henry. The sketch ended and Henry was expected for another routine in antoher part of the studio. But he was being forceably detained.

And so the screen went black for a few seconds and we had a breath of dead air. Finally Henry became disentangled and the show went on. Producer Lorne Michaels agonized about this later, but in fact, that dead air had been riveting in its way. You just couldn't tune out with such a provocative lull staring you in the kisser, and it proved that the show really truly was live and hadn't had every tiny flaw squeezed out of it by a tape editor or computer.

There was a time when even announcers were live, sitting in booths with their microphones, before stations started recording all announcements on tape cartridges. Those announcers could make mistakes, but so can egnineers. It's hardly uncommon now to hear that "Money movie will continue" right in the middle of the six o'clock news. Someone has put on the wrong tape.

During the live years, announcers contributed something personal to routine programs. Washington's WTTG was unreeling a particularly sloppy-boppy jungle potboiler one Saturday afternoon, when the station-break announcer couldn't resist pointing out that the film featured "Indian tigers in the heart of darkest Africa."

People who grew up with Chicago TV in the '50s may never forget insistent pitchman Marty Faye, who made obnoxiousness into an art form and was forever interrupting movies with spiels for used cars and vacuum cleaners. At least good old insufferable Marty had the intergrity one day to begin his movie-time commercial by saying, "This is the worst motion picture I have ever seen."

Through the years, such acts of creative spontaneity and personal communication have been largely eliminated from television, but at least we still have the occasional outrageous blunder to make the medium a little more fit for human consumption.

And a burst of dead air now and then doesn't hurt, either, unless it comes at an especially crucial moment in "Charlie Angels" or a Presidential talk show.

Dead air adds more than surpirse to television: it adds mystery as well. What happened? Who did it? And why? Maybe some day we'l see for real the little title card that greeted a pair of hapless TV viewers in a classic New York cartoon. They sat watching numbly as a sign on the screen declared. "We have temporarily lost the will to continue."