Let it be noted that on the same day Susan Sontag outraged an audience of self-proclaimed (and self-deluding) intellectuals of the New York left by belatedly discovering that "Communism is fascism, the most successful variant of fascism," a continent away a high school senior arose to confront her history teacher. "Don't give us that liberal bull expletive deleted ," said the bright student to the flustered teacher here in the supposed citadel of West Coast radicalism.

The millennium had not arrived, nor did that moment mean that wisdom finally had settled over the intellectual centers of America from coast to coast. But record these twin happenings as a small sign of a refreshing new realism that is dominating thought in the nation today.

The University of California campus at Berkeley, vanguard of so many movements that swept the country during the heyday of university activism in the last generation, is a prime example.

A few weeks ago the university released results of a survey of its incoming freshmen, showing that new students exhibit "a kind of selective conservatism," according to Austin C. Frank, the university's director of student research.

Among the findings:

There has been a surge of interest in raising a family among new students and a gradual return to quite traditional values, such as concern for law and order. Students strongly favor cracking down on criminals, for instance.

At the same time there has been a sharp drop in the number of students who favor legalizing marijuana. Fewer than half today would support it. That represents a major change from similar student surveys at Berkeley during the 1970s.

Many of today's new students say they want to enter well-paying professions and make a lot of money. Fewer than in past years say they believe the wealthy should pay more taxes.

When it comes to their self-defined political identification, another significant shift is being recorded. Twenty percent of today's Berkeley freshmen regard themselves as conservatives, a figure that has been rising in recent years. The ranks of those who think of themselves as liberals have been declining. Today 35 percent of the new group classify themselves as liberals.

The largest number of students say they are in the middle of the road politically. Only the smallest of percentages place themselves on the political extremes of "far left" and "far right."

Another Berkeley survey enlarges the portrait, this one involving the use of drugs and alcohol among the entire student body.

Gone are the days when drugs dominated the campus, if those days ever really existed as so widely and popularly depicted.

Although drug use has received the most public attention here since the 1960s, when Berkeley became imprinted on the national consciousness as the center of student protest, now the most serious and frequent problem is alcohol abuse. The same is true on other national campuses.

At Berkeley 93 percent of the students drink alcohol. A fourth of them say they drink several times a week or daily. Slightly less than half of the students say they have ever used marijuana. As for cocaine, the chi-chi drug favored in affluent salons in such places as Los Angeles, New York and Washington, only a fourth report ever having used it.REALISM 6

And the great majority of students who use either marijuana or cocaine say they take them quite sparingly. The usage figure comes out to between one and 45 times a year for those drugs. Only 9 percent of students who say they smoke marijuana say they smoke "several times a week or daily." Fewer than 1 percent use cocaine at that kind of frequency.

Drinking is by far the bigger problem at Berkeley. The university has a new alcohol awareness program to help students understand use and abuse of drinking. It was prompted by results of the survey, which showed that almost a quarter of the students may have some problems connected with drinking.

Nor is the campus the only sign of political change at Berkeley. The city, probably among the most liberal in America, is moving back into the mainstream. Last year the left suffered a setback when its slate of all four city council members was defeated by a moderate one. And just last week the citizens of Berkeley went to the polls and rejected a proposal to increase city services cut in the wake of Proposition 13's slashing of municipal revenues.

Taken together, all this adds up to evidence of major change, a kind of mellowing of the mood, as it were, of this lovely American campus. That portrait is true, but it's also deceptive.

Beneath the surface of what appears to be a normal student body in a typical campus environment of the 1980s, a campus tempered by experiences and now shunning political extremes of right and left, Berkeley bears the scars of extremism and past political polarization. From Chancellor Ira Michael Heyman on down, faculty members and administrators live with the memory of a period that came close to destroying one of the world's great centers of learning. Some of those old problems still afflict this great university.

A year ago, on Charter Day, a small group of protesters disrupted a ceremony at which Heyman was being inaugurated. Employing the old techniques--shouted obscenities, sieg heils and bullying tactics--they tried to drown out the speakers. Now Heyman ponders whether to hold a similar public Charter Day ceremony, and worries aloud about the subversion of the real principle of free speech and expression that the protesters supposedly still pretend is their ideal.

What has happened, as Heyman says, is that remnants of the radical groups are so isolated from the norm of campus thinking and acceptance that they are driven increasingly to more extreme actions to gain attention.

Extremism, though, is not the real problem at Berkeley. Here, as on other American campuses, the main question facing students and administrators alike comes down to one of money in a time of severe budget restraints.

Already stirrings of protest against Reagan administration policies are being felt at Berkeley. That question and others, such as American involvement in El Salvador, are being approached with an admirable absence of rhetoric and a high degree of seriousness. After spending a week meeting with students, faculty members and administrators, a visitor comes away with a strong and positive impression about the currents flowing through Berkeley today.

Unlike the stormy past, the debates here are proceeding with less sound and fury and more realism. They are less dramatic, but in the long run perhaps more significant.