Berlin — Frederick II of Prussia rides again. His statue, erect in the saddle, has been rescued from oblivion and moved to the center of East Berlin's broad Unter den Linden. And Communist Party boss Erich Honecker today can even be heard calling him, once again, ''Frederick the Great.''
On the other side of the 21-year-old wall of concrete, barbed wire, and tank traps, West Germans of all ages and backgrounds recently flocked to see the first post-World War II exhibition of Prussian artifacts.
The German people, whom President Reagan comes to visit this month, have reached a delicate, sensitive moment in their national revival. There is ferment on both sides of the great national divide. In the East, it is stifled, almost inaudible. In the West, widespread, often raucous.
Where are we heading? What is our identity? Who are we?
These questions are troubling West Germans all across the political spectrum. Outsiders who prejudge the answers, however, or automatically assume that a revival of much-feared German nationalism is around the corner, may do more harm than good.
''It is a process of normalization,'' says one of West Germany's leading politicians, former Federal Justice Minister Hans-Jochen Vogel, who now heads the Social Democratic Party's forces in Berlin. ''Our friends should not misunderstand it. We are in a period of revitalization of history.''
But the sort of national identity that carries Britain through years of torment in Northern Ireland, through the patriotic fervor of the Falklands conflict, is denied the Germans. Twelve years of Nazi excesses (from 1933 to 1945) blasted a gaping hole in the nation's history and sense of identity. And today the substitutes are proving fickle.
For West Germans, the initial ersatz nationalism of the Common Market has faded. Interminable European Community wrangling has taken its toll of youthful idealism.
The financial nationalism of a powerful deutsche mark, too, has lost its glitter. Recession, nearly 2 million unemployed, and today's questioning of more-is-better ethics have seen to that.
The nationalism of anticommunism has been eroded by an Ostpolitik that has brought far more tangible benefits to West Germans than did detente to most Americans. And while the commitment to the West remains deep and strong--the polls showing 80 percent steadily favoring support for NATO --the almost reverential respect for the United States has suffered varied blows.
Vietnam and Watergate left their mark. Early Reagan administration rhetoric added to concern about American judgment and reliability, playing into the hands of the radical minority who would shift their country toward a more even-handed position between East and West.
The result of these combined events is a sort of slumbering unease, an almost undefinable anxiety that seems to permeate society from top to bottom. And into this mental vacuum have slipped the growing peace movement--and the ''green'' parties with their claims to guardianship of both the environment and political morality.
The immediate target of the peace movement, supported by the Greens and Protestant churches, is NATO's planned deployment of new nuclear missiles to counter the Soviet SS-20s. Many West Germans, not just the young, question whether new missiles mean more security . . . or merely more targets. Beyond that, many of them doubt the whole morality of the nuclear age. They will be marching by the thousands June 10 in Bonn and (more rowdily) here in Berlin June 11.
Television cameras and satellites will flash the banners into American living rooms. And the anti-American aspects of the basically antinuclear theme will vastly outweigh the silent majority's invisible pro-US sentiment. (Some 73 percent of West Germans rate the US favorably, according to one recent poll, while only 46 percent of Britons, for instance, hold the same favorable view of the US.)
This situation is deeply frustrating for many West Germans. And the Christian Democrats' pro-West rally June 5 is not expected to readjust the propaganda impact on American watchers.
What the TV cameras also are unlikely to show is the parallel questioning quietly under way on the other side of the German divide. It is in the very nature of the totalitarian regime in East Berlin that it assumes credit for being the ultimate authority on peace even while it tries to stamp out its own peace movement.
Centered in the churches, the East German movement is a much more subtle version of its Western counterpart. Apart from one lone demonstration, no marches or banners there. Similar doubts about nuclear missiles become instead the subject of oblique sermons or of shoulder badges (now also banned) displaying the Soviet swords-into-plowshares statue at the United Nations.
In addition, East Germans, though much better off than most of their East-bloc comrades, are having to tighten their belts. They are in debt to the West and Moscow. They face food and energy shortages. They have clamped down on the imports that once provided a safety-valve for envy of their big, Western brother next door. The regime is hemmed in politically and economically.
Perhaps, then, the very tentative groping for historical roots to be found on both sides of the border is not so surprising. The 500th anniversary of Martin Luther's birth provides another such opportunity next year. (The East Germans seem to see no irony in their communist chief himself chairing the committee to commemorate the Protestant Reformation's towering figure.)
But this common revival of the past should not be misread. Reunification remains an ultimate possibility for many Germans. But it is certainly not a foreseeable objective. It has no impact on West German policy. Nor is the great majority of West Germans prepared to pay the price: neutrality, at best.
Hence, to overreact to West Germany's modest and still confused adjustment in its sense of balance and identity risks being counterproductive. That would more likely increase, rather than lessen, West German-American frictions. And that, in turn, could fuel much more dangerous potential changes which are currently still well out of sight.
The postwar rebuilding of West Europe is largely done. The forces of material gain are losing their allure. Europeans are looking for new goals, new ideals, a fresh view of the future.
Divided, at the core of Europe, Germans find the outlook especially bewildering.