BOTH THE BLACK and white students could tell he was a visitor on campus because he sat at the wrong table. Blacks seldom ate in that part of the cafeteria. They usually carried their trays to the "black section," in an adjacent room.

There were no printed signs, no written rules to alert him to the practice. The visitor could be forgiven for his ignorance. He would learn in time.

That is the way things are done at Duke University in Durham, N.C., at Cornell University in Ithaca, N.Y., and at many other predominantly white campuses across the country, where 72 per cent of the nation's 948,000 black college students attend school.

Twenty years ago, most of those black students would have attended black institutions, if they had been able to enroll at all. But then official race barriers began to tumble at colleges and universities during the 1960s, a period marked by considerable turmoil. At some bastions of higher learning, like the University of Alabama at Tuscaloosa, whites fought to keep blacks out. At others, like Cornell, the new black students demonstrated, sometimes violently, for more black faculty, more black administrators, more black students, more black facilities.

Today the campuses are "quiet." At least the loud, overt racial hostility of the 1960s has faded in many places. But it has been replaced by something else, by a strained and separate peace that makes one wonder about the dream of racial harmony in America, about whether, after the court edicts have been issued and the laws adopted and the army of enforcers grown weary, there is really a desire or a will for racial harmony after all. Pride and Prejudice

THE DOUBTS return over and over again when one visits colleges and universities, talks with faculty members and administrators and the students who are to be tomorrow's society shapers, tries to fathom the multiple factors contributing to today's separate racial peace.

There is, for example, "culture friction" - literally two cultures rubbing each other the wrong way. The kinds of music played over campus radio stations and on cafeteria jukeboxes can lead to disputes between the races. Or, as happened last Sept. 30 on Duke's main campus, "culture friction" can come when a black fraternity and a white fraternity attempt to hold separate events - a "step (marching) show" and a "celebrity auction" - in the same place at the same time.

There is "culture shock" - the overwhelming sense of isolation, fear and inadequacy many black college students say they feel when they come to a predominantly white campus, especially if that campus is in an isolated, predominantly white area.

There is pride and prejudice - sometimes indistinguishable from one another. They show themselves in what whites call "tradition" - usually meaning all-white fraternities, sororities and campus clubs - and they frequently show up in what blacks call "black solidarity" - usually meaning black student coalitions, associations and unions, black yearbooks, black newspaper, "black studies" and sometimes "black homecomings."

There are "special education programs" for minority students. Many blacks say these programs hurt as much as they help, getting them into the university on the one hand and stigmatizing them as "inferior" on the other. It is difficult, if not impossible, they say, to enter interracial social relationships from a position of weakness.

There is sheer economics - the tuition crunch. More colleges are finding it difficult to provide large numbers of students with financial aid. Many white, middle-income families, some with two or more children in college, are having a hard time keeping their children in school because of increased costs. The white parents are appealing to the colleges and universities for help. Many black students from lower-income families are afraid the schools will provide that help - at their expense.

There is "careerism" - the fierce, often myopic competition for grades, degrees and jobs that consumes many blacks and white alike. A black graduate student in the Department of Agriculture and Resource Economics at the University of Maryland in College Park remarks: "I don't have time to socia lize with the white person. I don't even want to relate to the white person. I just want to get my piece of the rock from him and get the hell out (of the university)."

A white undergraduate student at Duke, pressed by a friend, a transfer student from Italy, to explain her refusal to eat or talk with blacks, replies: "I never thought about it. I don't have time to think about it now. I have a chemistry exam tomorrow.

There are old taboos against interracial dating and loving. The taboos die hard bot only at Southern campuses. Similar feelings exis at schools like the University of California at Los Angeles, Cornell and state universities in lowa and Maryland, even though interracial couples can be seen with more frequency on those campuses.

There is the "reverse discrimination" issue. The pending Supreme Court case in which Allan Bakke claims he was unconstitutionally denied admission to the University of California's Davis medical school because he is white has helped polarize blacks and whites on other campuses.

"Nobody wants to be branded as a racist.[but] it appears that anyone who dares to speak out against discrimination against whites is termed as such, "two white Cornell students. Peter Coleman and Marc Fine, wrote recently in the student newspaper.

Ron Robinso, president of Cornell's Black Student Coalition, replies: "This [letter] shows that when writes whites are asked to give up some of the things they've enjoyed because of past discrimination, the [white] liberals become conservatives. You can't shake hands and pal around with people like that. You can't even start talking about socializing until you address the problem of oppresion."

Finally, there is peer pressure - ostracism. Blacks who attempt to "mix" with whites frequently find themselves cut off from other black students. The same can happen to white who cross racial lines.

At Duke, student T.C. Adams says he is troubled by the segregation that exists the classroom setting. "It bothers me because I came to this university to study to become an administrator," states Adams, who is one of about 400 blacks among the school's 8,600 undergradute and graduate students. Adams is also chairman of the undergradute Black Student Alliance.

"When I leave here, I would have gained nothing to help me deal with other cultures," he says. "These [cultures] could be Jewish, suburban, white or whatever . . . I've missed dealing with people on a very basic level. We've experienced knowledge [in class] together, but outside of that atmosphere, casually talking, that's what I've missed. It's that kind of experience that gives you an idea of what people are all about."

Ironically, many white Duke students complain that they are missing the same thing. Some have come together with blacks in weekly meetings to discuss "the problem." But most of the students, blacks and whites, are moving through the university oblivious to one another.

The reasons for the social separation at Duke appear to have more to do with peer pressure than anything else. Fraternities and sororities abound and function as tightly knit groups. There are 17 white fraternities and 10 white sororities, three black fraternities and two black sororities. There are no laws barring admission on account of race. But, as one student put it. "There is a general understanding: Don't mix."

The Harvard Exception.

HARVARD IS THE exception to many academic rules, an unrepresentative American campus, and it is no different in this case. Less strained race relations are evident at Harvard, where there are about 560 blacks - 6 per cent - among the school's 6,246 undergradutes.

Black militancy, which marked Harvard campus life in the late 1960s, is all but dead. The dashikis and large Afros have been replaced by moderate hair lenghts, crew-neck sweaters and the Brooks Brithers jackets associated with the Harvard life.

Martin Kilson, a black professor of government noted for his attacks on "self-segregation" by blacks, contends that part of the change has come about because Harvard does not "thinker with its admissions standards," does not lower academic requirements and therefore has few blacks "who can't deal with culture shock."

"I have this theory," says Kilson. "Schools that never tinker with their boundaries [standards] for admission get a more homegenous black student group. The more homogenous the group, the more likely it is to disperse within the overall university community. The more heterogenous the group - especially if it was admitted through tinkering with the boundaries [of admission] - the more likely it is to substitute an exclusionary facade to cover up feelings of fear inadequacy."

"I'm certainly optimistic that things are getting better here and at other Northeastern schools," he adds, implying that campus race relations are also affected by region. "Things are not moving fast enough to suit my taste, but they are moving."

Indeed, black Harvard students are finding their way into previously all-white campus organizations like the schools daily, the Harvard Crimson, the Harvard-Radcliffe Democrats and the once exclusive "final clubs," Harvard's version of fraternities.

However, as indicated by Gary Martin, president of the school's Black Student Association, what is taking place in race relations at Harvard is more of a strategy than a trend. It is preparation for "infiltration" into government and business jobs - positions of power that could be used to help the rest of the black community, Martin states.

An incident last year shows the Harvard blacks will come together when their interests are threatened. The Harvard Lampoon published a cover showing a black Harvard student shining the shoes of white "John Harvard." The blacks did not laugh. Neither did they loudly demonstrate their displeasure, as they might have done several years ago. Instead, they presented a petition with about 600 names to Archie C. Epps 111, black dean of students. The matter was taken up with the Lampoon and solved amicably, Martin says, "We still feel that blacks are in a disadvantaged position, and that kind of thing just . . . serves to inhabit our advancement," he explains.

The incident, though handled quietly, prompted creation of a faculty-student committee to review the black-white situation at Harvard. A preliminary report is due in the spring, a final report next fall.

According to Martin, blacks on campus are maintaining their black identity while pursuing wider goals. "There's a lot more substance and less show," he says. "Discrimination is a lot more subtle now, and we have to be much more sophisticated to deal with it."

However, the racial situation at Harvard - the apparently free contact between blacks and whites - is seen as something of an aberration, a deviation from what is generally taking place. Even a die-hard integrationist like Kilson admits that.

"There isn't all that much [racial] tension, but you have to remember we're talking about Harvard College and the most educable black students in the country." Kilson says, "These are not the typical Negro college students." "White Folks Do Not Like Us"

Precisely, says Katrina Hazzard, a black graduate student at Cornell, about 300 miles west of Cambridge, Mass.

Harvard is an elite school that has the luxury of picking the top black and white students. Blacks and whites at Harvard tend to get along better because the real difference between them is skin color. Hazzard notes, echoing a view of others [blacks and whites] who claim familiarity with the Harvard experience. "The more Africanisms you maintain, the more you insist on your blackness, the poorer you are, the more difficult will be your life on a white campus," Hazzard contends.

Cornell is also an elite school - academically demanding and costly, about $7,000 annually for tuition, fees and living expenses. Of the 16,979 students attending Cornell last December, 670 were blacks.

At first glance, Cornell appears to be racially peaceful - certainly more peaceful than it was in April, 1969, when protesting blacks took over Willard Straight Hall, a student activity and dining center, and emerged brandishing guns.

Today, black and white students emerge from classes in animated discussion, an occasional interracial couple can be seen going about their business on campus and the racist grafitti of a decade ago seem to have disappeared from lavatory and other campus walls.

But both black and white students, and their racial counterparts in the university administration and faculty, are quick to warn that the calm is deceptive and capable of crumbling from a tuition increase, a potential change in the method of awarding financial aid on a basis of merit rather than need, the outcome of the Bakke case or the failure of the university concert committee to book black artists.

"I'm pretty optimistic about [improved race relations] right now . . . but I see some [disruptive] things in the wings which are always back there," cautions Cornell Provost David Knapp.

"The one thing we blacks consistently is that the white folks do not like us and not want us," says Hazzard. "If the blacks had a day of absence at Cornell, nobody would miss us."

Whites at many campuses disagree. Instead, they increasingly see themselves as being put upon by blacks and have become pore vocal in expressing their resentment. In the 1960s, for example, the white-dominated school papers in the University of California system generally supported black demands. But now things have changed.

Most of the nine school papers serving the system, including the ones on the Berkeley and Los Angeles campuses, have come out squarely in favor of Bakke. At both schools white radicals and minority students have staged demonstrations against the pro-Bakke editorials. The demonstrations included burnings of issues in which the editorials appeared.

Sally Garner, editor of the UCLA Daily Bruin, says white students now are more willing to challenge blacks on their opinions, and that angers some blacks. "It's a change in attitude between our generation and the one before us. "We simply don't see it the same way as minorities, and we're not afraid to disagree with them."

Her positions has led many black student leaders to denouce the Bruin as a racist publication. But she regards the charge as a scare tactic and has vowed to ignore it.

" 'Racism' is like the new word around here. It's like a few years ago when they were calling everyone 'fascist.' It's a term that everyone uses, and there's no way of substantiating it," she says.

Maybe so. But at UCLA's black student association office, a visitor can see photos of anti-black grafitti. The black student officials say their office has been the target of pretty vandalism several times during the year. And they say they fear the rise of white student rights organizations within the university.

The new racial tension has not helped change black-white patterns existing at UCLA and other universities for the past five or six years. For example, anyone walking on the UCLA campus, a few miles west of downtown Los Angeles, can see evidence of separation between the races - with a difference.

Whites and Asians - the latter group being far more numerous than blacks at UCLA - commingle easily. Blacks - walking on the quad, eating lunch, studying in the library - tend to stay to themselves. The Schoolhouse Door

MUCH OF THE same thing happens between blacks and whites at the University of Alabama. Gov. George C. Wallace has long since left the schoolhouse door, but the racial fears that put him there in the first place are about as strong and evident as they were on that June day 14 years ago.

Item: Blacks not expressing a roommate preference frequently find themselves with a white roommate - for a white. On the day set aside for room swaps, almost all of the interracial roommates select new mates of the race. Parent pressure causes most of the separations, according to a university counselor. "You always make those changes [demanded by parents], but it goes against your grain," she says.

Item: Black and white fraternities and sororities are as racially separated - voluntarily, of course - as they are at many other predominantly white universities. W. Baker Crow, a 22-year-old senior from Birmingham who is treasurer of the University of Alabama's intrafraternity council, believes things will stay that way at his school. "That's just the South," he says. "Tradition. It's been that way over the years."

When blacks inquire about white fraternities. Crow advises: "You can sign up, but you probably won't get a bid . . . We never try to run them [blacks] off, we just point them in the direction where we think they would be happier." No one knows of any whites who asked for those same directions - to the four fraternities and four black sororities which arrived on campus in the last five years.

Item: One university official remembered a recent case of a black girl pledging for a white sorority. The official says she was struck by the black girl's "overwhelming naivete in thinking she could be a part" of the white group.

Interracial dating at the University of Alabama C. Suzanne Kennemer, a sophomore from Kansas, puts it simply: "Down here, it really upsets people."

She remembers the comment of a friend who fumed at seeing a black man white woman together at a dance. According to Kennemer, the friend said: "He ought to be whipped and she ought to be shot, because any Southern woman should have more respect for herself."

There are 1,500 blacks among the 15,500 students attending the University of Alabama. Many have banded together in a black student alliance. They have found safety in numbers, and their insistence on "solidarity" can sometimes be overwhelming, according to blacks and whites on campus.

But the blacks say the "solidarity" is necessary to "survive" at the university. Their counterparts on other predominantly white campuses say the same thing. Many whites and blacks seem to prefer the arrangement.

"It's like an invisible wall," says Vaughn M. Stewart, president of the student government association. "If there were public conflicts you could, perhaps, see some changes coming. But everyone seems content . . . kind of the silence before the storm." More of the Same?

SO WHAT of it? What does this augur for our society? What kind of policies can the nation expect when many of the current crop of "the best and the brightest" are moving through college oblivious to, or angrily aware of, one another?

The kind of policies we already have, says Kenneth Clark, the black sociologist noted for his work in race relations, education and urban policy. "These students are being trained to take their racial views with them into society. They're being trained to carry on a segregated society. Rather than trying to learn to counter the status quo, they're being trained to keep it going."

"Why are you so surprised by what you find on the campuses?" asks Samuel Halperin, director of George Washington University's Institude for Educational Leadership. "I just think people still tend to seggregate themselves in every place except work. The stage we are at now is that you look for a lot of goodwill and non-discrimination, but not integration. The majority of people still tends to keep to themselves. With balcks and whites, it's ging to take a lot longer. We're just lots of years away."