THE GREAT DIVIDE; By Studs Terkel; Pantheon Books; $18.95; 50 pages.

After the clear voices that fixed the Great Depression and World War II in our minds - set down respectively in "Hard Times" and "The Good War" - many of the voices in "The Great Divide" are an unresolved mumble of uneasiness, contradiction and purposes hidden from themselves.This makes Studs Terkel's record of America's thoughts about itself in the late 1980s harder going than its predecessors. The interviews are less graphic, and they lack the exhilarating self-knowledge. But this is also their success.

Terkel reports a patternless America, less afflicted on the whole but immeasurably less self-aware. If the voices in the other books clearly and movingly evoked two national catastrophes, their resonant timbre redeemed their subjects.

The national catastrophe in "The Great Divide" is the voices themselves, their blurring, the degradation of their perception.

In an illuminating preface to these 95 interviews with Americans of all classes and conditions, Terkel tries to pinpoint the difference. Above all, he says, it is a loss of memory.

Terkel quotes Jacob Bronowski's dictum that today the average person "has far more facts about the world than Isaac Newton ever did, though considerably less truth."

If in one sense, Americans are more culturally homogenized - partly through television - in another sense, they are more isolated from each other. The various solidarities of a war and a depression are less evident. There is plenty of poverty around, but it is more likely to breed guilt than defiance.

We have homelessness now, as we did in the '30s, Terkel tells us. Then, we had Hoovervilles - makeshift ramshackle communities that provided shelter and a political statement. Why are there not Reaganvilles now? he asks.

His answer is a word-shift. Once, the poor were "victims"; now, they are "losers." The dimensions of our social problems, the gulf between those who are making it and those who aren't, is as wide as ever, he writes.

"If there is a core difference between then and now it is language."

Time and again, as Terkel interviews students, professionals, businessmen and other members of the more-or-less prospering mainstream, he finds an unsettling disassociation.

It is as if prosperity were not something planned for, worked for and achieved, but the equivalent of a Bangladesh flood, sweeping its well-heeled victims helplessly along. It is a prosperity that shares a characteristic traditional to poverty; that is, a sense of helplessness about your life.

One of his more exotic finds is a man who considers himself a liberal Democrat, and pro-union. His business consists of trucking food and recreational equipment into factories that have been struck and are using scab labor. His menu features steak and lobster tails, and he finds it useful to barbecue outdoors, so that the smell will reach the pickets.

These people, you might say, are coloratura pigs. They denounce with melodic brilliance. They emit high, bell-like overtones of anger and protest, before lowering their faces back into their troughs.

Others, less aware of the ironies, mingle ready-made opinions about the need to make money with vague worries that perhaps they should be working for change.

"I think I'd like to contribute to society in some way," says an advertising copywriter. "I don't know what that would be. Right now, I just sort of give bums money on the street."

Some are desolate and touching. A recent graduate of a Catholic school goes to work as a brokerage runner and quits because he still believes there is something more important than making money, even if he doesn't quite know what it is.

Terkel tries to be hopeful where he can. At an Arkansas college, the fundamentalist student body was emphatic in condemning AIDS victims. When a film showing the victims' sufferings was put on, on the other hand, many of them wept.

The clearest views, and certainly the most moving visions, come from those outside the mainstream. There is the extraordinarily vital voice of Wilma Green, a young black woman who works organizing tenants from the office of a Chicago alderman.

It's her voice and also that of her mother, a mother who brought up 12 children, saw that they all did their homework, commanded Wilma to hold her head up despite her pregnancy at 15, and recently boasted that her daughter was "making trouble and getting paid for it."

There are Iowa farmers, eloquent about their plight, and perhaps more similar to the people in "Hard Times" than any others in this book.

"Who's going to stay up with the corporate sow?" asked one farmer's wife, commenting on the sell-off of small farms, where livestock is individually cherished, to large agribusiness firms.