Tonight's "Bill Moyer's Journal," at 9 on Channel 26, is a conversation with Jacob Timerman, the Argentine intellectual and publisher who was imprisoned, tortured and finally deported from his own country by military officials there.

Timerman's reflections on the method and effect of the torture have been fairly well circulated now, and a book has been published; but once this repeated information is out of the way, Moyers follows Timerman through a calm but chilling analysis of not only the political situation in Argentina but the way that Timerman thinks the world is turning

He describes the present regime in Argentina as virulently anti-Semitic ("They are Nazis . . . a murderer's regime") and strongly criticizes the Reagan administration for its stand on, or its brushoff of, human rights issues. Apparently "human rights" under the Carter administration was more than the buzz-phrase some of us thought, because Timerman credits the Carter policy with helping get him out of jail.

"Your present policy is the same as the Soviet Union," Timerman tells Moyers. "The Soviet Union's official stand, on human rights, is: We shouldn't interfere with anybody. Everybody does whatever they want. And this is what you are doing now."

Wait; it gets worse. "Are you saying history is repeating itself?" Moyers asks. "Yes," Timerman replies, "history is repeating. But what worries me [is] that silence is repeating. . . .

"You are trying now in Washington to go back to the silence of the years of Hitler," Timerman says. "This quiet diplomacy, this silent diplomacy -- this is a way of silence; what you are trying to do is to say that it is better to have an anti-communist, a killer, than to have human rights and a democracy in Argentina." The only thing Secretary of State Alexander Haig cares about, Timerman says, "is anti-communism. And that was the position of Hitler. This is why the world was silent when Hitler came to power."

The view of the world that emerges from this discussion is of a planet on the brink of a thousand explosions. "My dear Mr. Moyers," Timerman says, "international terrorism is all connected. All of them are connected -- in one way or another."

The hour is not strident or shrill, however, and there is a human story being movingly told. Timerman recalls how one of his torturers in Argentina took time off one day to ask his advice on what career the man's young son should pursue, as if the two were chums. When Moyers points out that Israel is supplying arms to the anti-Semitic regime in Argentina, as is the Soviet Union, Timerman exclaims, "What to you want me to do -- commit suicide, here in front of the cameras?"

Moyers is, as usual, the straightforward questioner, emotionally and intellectually involved but never a grandstander. He also helps translate some of Timerman's heavily accented English; when he says what sounds like "cows," Moyers points out that Timerman is trying to say "chaos." 'September Song'

WJLA-TV celebrates Senior Americans Month and continues its commendable "Assignment 7 Special" series with "September Song," a predominantly thoughtful and worthy hour, at 8 tonight on Channel 7.

The first half of the program, shot on film by the tireless and talented Paul and Holley Fine, focuses on three area elderly people who've refused to sit down and grow old. Louis Price, 87, volunteered for the foster grandparents program at a local day-care center. Dorothy Whipple, 80, retired from the medical profession but continues to counsel medical students at Georgetown University.

And Brooke Johns, 87, once the star of a local kiddie show called "Uncle Brooke's Farm," keeps busy with his own restaurant and with entertaining fellow members of the post-60 set at nursing homes. "I'm a selfish old son-of-a-gun," he says roguishly. "I don't want to grow old. I'm not going to."

So far, so -- well -- far. But the second half of the program, a studio discussion among elderly citizens and representatives from the National Council on Aging, goes a bit thick on the nicey-nicey sauce. Host Paul Berry introduces the segment by saying he has "some very, very lovely people" for us to meet, just as he opened the film segments by saying he had "three very special folks we want you to meet tonight."

Far be it from anyone to doubt their very lovely specialness, but the program's tone toward the aged is so rapt and delicate that it becomes a patronizing and demeaning attitude of its own. This hour's heart may be in the right place, but its tongue occasionally ties itself in a knot. 'The American Family'

Here's another crisis for you: "For Better? For Worse? The American Family," a Capital Cities syndicated special that explores alterations in the structure of the family unit at 8 tonight on Channel 5. Host Robert MacNeil, on loan from PBS, says, "What we know is, The American family is undergoing a profound change."

The rest of the hour looks at the changes as personified by young couples in Somerville, Mass., who get group counseling before walking down the aisle; habitues of a New York singles bar who say they don't have the values their parents did; a mind-boggling mass divorce court in San Diego, Calif. (answer six questions, pay $57.40 and you're in Split City); and a family crisis center in Pittsburgh, where a social worker declares, "There are people outside the walls of that house who impact on that house daily." Are these people throwing themselves at houses in Pittsburgh?

Examples of how social programs have sprung up to deal with the changing attitudes toward marriage and raising children sometimes come off, on this program anyway, as just institutionalized whimpering. When the bearded owner of the singles bar begins a sentence with "The pressures in our society are so great," you may want to screeeeeeam. There is much, talk of relationships ("I'm in a relationship now," says a divorced man) and of expressing Our Feelings.

At a workshop for the children of divorced parents, the young tots put on a puppet show to expess their feelings, and the adolescents put on a radio show to express their feelings. And the parents, sitting attentively in chairs, applaud each performance to express their feelings. Hey, what is this? Show business? Feel business? The fact that so many groups and centers have sprung up to deal with private matters in a public way suggests that the hippie commune idea of the '60s has survived and been adopted by the old messed-up middle class.

"American Family" is not particularly comprehensive or definitive, but it is a respectable hour of fitful insight, whether taken at face value or as a symptom of the very problems it is trying to document. 'The Robert Klein Show'

NBC reportedly kept tonight's Robert Klein special on the shelf for six months before giving it an air date. We all know that networks are riddled with jackanapes and miscreants, and it would be oh-so-gratifying to report that they had overlooked a gem. Unfortunately, their reticence is justified by the special itself, in which potentially light and bright comic ideas are somehow given the weight of the Ile de France.

"The Robert Klein Show," at 10 tonight on Channel 4, opens promisingly. Klein asks for questions from the audience and soon is all but buried under pointed inquiries about a certain Suzanne Pierce whom he dated once in high school and then cruelly forsook.

But the mocking self-indulgence soon congeals into just plain self-indulgence. Klein's mezzo-soprano wife. Brenda Boozer, is trotted out to do vocal exercises on which Klein ineffectively comments. In other sketches, a caller to a radio hot line says, "I've got a pencil up my nose." Judd Hirsch stalks stonily through a dull taxicab routine and, as a star dog's agent, takes a lunch with his client to tell him "Where's Bowser?" has been canceled.

Two bright spots: Andrea Martin, of NBC's hilarious and resourceful "SCTV Network/90" (whose third show airs at 12:30 tonight, after Carson) as Edith Prickley, macho woman, and as Indira Gandhi, peddler of hair dye; and Arnold Stang -- yes, Arnold Stang -- who doesn't seem to have aged an inch since he was a capital stooge to Uncle Miltie and others in the TV '50s. Arnold is as funny on purpose as the Charlie Daniels Band, performing "God Bless America Again," is unintentionally.