Bonn — ''We can't go on the way we've been going with the environment; we must find a new way,'' declared university nutrition student Monika Fabian. She had already voted for the ecologist-nuclear pacifist Greens by mail ballot. She was knitting as she listened at one of those Green Party bull sessions, to proposals for combating acid rain, buying France's excess electricity in lieu of building more German power plants, and imitating Japan in life time employment (if not in grindstone work ethic).
Yes, she thought the Greens did represent West German youth in both their environmental and missile protests. ''The established parties just try to justify the old ways and cling to them. But from a Christian standpoint, one should be responsible for life and the earth rather than destroy them.''
Surprisingly, perhaps, conservative voter Hans X. agreed the Greens and the antinuclear movement are valuable representatives of today's youth. He, like the majority of passengers on the early morning Cologne-Hamburg train, was a military recruit who had spent his customary weekend at home, thanks to the free railroad travel offered to draftees.
He found unrealistic the peace movement's hope that unilateral Western restraint on arms would induce the Soviet Union to reduce its weapons. But he thought the antinuclear challenge to ''mindless arming and more arming'' was a healthy thing, as was the Greens' challenge to mindless pollution.
In contrast to 50 to 80 percent of West German youths between 15 and 25 years of age, polled by German Shell Oil Corporation in 1981, Berlin University political scientist Richard Loewenthal does not have uncritical sympathy for the Greens, the peace movement, squatters, or other protest groups. Loewenthal, with decades of experience in intramural Social Democratic battles, is leery of the Greens' leftist protest - and of the Social Democrats' current campaign to steal the Greens' clothes.
He has consistently warned against the danger in some students' cynicism about democracy, their intellectual preference for equal distance between East and West, and their ''spirit of total criticism'' toward West German and Western institutions.
He rejects, however, conservative suspicions that leftist youth movements of today are repeating the flaws of pre-Nazi rightist youth movements during the 1920s by not clearly rejecting violence, by wallowing in cultural despair, by glorifying nature in an antimodern backlash, and by yearning for a special (unified) German status morally superior to both East and West.
What Professor Loewenthal does hope is that youthful discontent with the existing world can quicken traditional Western values. But he is uneasy about the transformation of the utopian student revolt of the late '60s and early '70s to today's ''belief in catastrophe.'' He resists the despair and nihilism so ''obstructive and damaging to the evolving interpretation and further development of Western values.''
So who's right? Were the 400,000 who demonstrated peacefully in Bonn against new US missiles in October 1981 carrying the banner of the future? And are the students identified as left extremists by the equivalent of the FBI - fully one-third of elected university student government delegates - doing so? Are political-science students who daub walls with ''NATO out'' slogans more typical than 80 percent of law students whose goal, says Bonn law student and Green supporter Martin Rubbert, is money?
More broadly, are these young people the post-materialist idealists who will save the German soul? Or are they a pampered generation that has been handed so much peace and prosperity that they now think only of demanding ever more rights and never of owing duties to society? Do they so take for granted the Northern Hemisphere's rapid economic growth from 1950 to 1973 that they become cross and blame the West German system when their own rising expectations of social benefits now collide with recession?
In a way, these are the eternal questions that might be asked about the advancing generation in any Western society. And yet these - like so many other questions about this vigorous, introspective nation - are fraught with special urgency for being German questions. And they are fraught with special traps for the observer in the contradictory nature of so much of the evidence.
So far, the best attempt to form a pattern out of the kaleidoscope has been a polling of attitudes of 1,077 youths between 15 and 25 years by the German Shell oil company youth research foundation. The major findings were:
* 58 percent view the future with pessimism.
* 52 percent reject the established political parties.
* But 99 percent are not attracted to extremist parties of either right or left.
In addition, the study found working-class youth to be considerably more conservative than better-educated youth in attitudes toward protest movements.
Asking the questions a bit differently, another poll, the EMNID poll, found an even greater mistrust of the state and the traditional parties. Some 69 percent of the 25-and-under crowd queried in 1981 deemed parties other than the Greens incapable of solving today's problems.
These and a number of other indicators point to a growing ''post-adolescent'' subculture, more or less in the American style, that is distinct in mores, fashion, and language from the ''real'' adult world. There may not be the same cult of youth as in America. In this more rigid society, there are certainly not the same opportunities in business, government, or academia for the meteoric rise of brilliant and brash young stars. Economic prosperity, however, together with a great expansion of the university system and comprehensive student grants , has nurtured a self-contained student world that is new in Germany.
For many students this is still a period of prudent conformity. Germany does not have the American credo of the no-questions-asked second start. And in this still rather homogenous society Hans X., for example, is not going to jeopardize his future career by getting into his dossier any tourist trip to Eastern Europe.
For many other youths, though, the period of suspension before they join the hemmed-in adult world of constant compromise is one of political and philosophical experimentation. This might mean the kind of idealism about ecology or peace that Professor Loewenthal hopes will revitalize democracy. Or it might mean leftist intolerance of conservatives that is the mirror image of some conservatives' intolerance of leftists.
The paradoxes and contradictions abound. Some of today's university-age Greens view the protest generation of '68 as having sold out to the establishment by now - and view today's high-school pupils as retreating to apolitical personal conservatism. Some high school pupils view their five-year-older siblings as having given up in their protests.
In a further anomaly, the Shell study reveals that 88 percent of young people anticipate owning their own house at some point in the future. Particularly in a society in which owning one's own home has long been a conscious symbol of conservatism, this finding would seem to call into question the real depth of enthusiasm for protest - and, for that matter, the real depth of that proudly displayed pessimism. Can these apparently conflicting attitudes and evaluations be resolved by some explanation of maturing ages? Do yesterday's radicals become today's conservatives?
Sometimes yes, sometimes no. The '68 protesters who proclaimed a ''long march through the institutions'' may by now be young lawyers or MPs and own their own houses. But they are changing the institutions they have joined. Quite a few of those young lawyers are active in civil rights rather than corporte law - and are running as Green candidates in the 1983 election.
Under this pressure the Social Democratic Party is undergoing a visible Greening this year. And the conserva-tives are competing with the Social Democrats in writing tougher antipollution laws for industry.
Individuals do change, too, of course, sometimes in a remarkably short period of time. The best measure of this, perhaps, is a watchful mother's eye.
''When we arrived (back in Germany) two years ago with our two teen-age children, we were shocked and bewildered by the youth scene we encountered,'' recounts a Bonn mother. ''When I enrolled my children in their new gymnasium, a tired-faced teacher pointed down to the schoolyard, where the youngsters crowded around smoking. ''
'Look at them!' she said, 'a generation without direction, and we cannot give them any direction.'
''I formed a very harsh and negative judgment about those loads of high school youngsters who came to call on our kids, hanging around for hours, discussing their problems, of which they seemed to have too many,'' the mother continues. ''. . . Compared to us, who had such a strict education, they seemed to show little endurance, physically as well as psychologically.
''The family was for us a secure place, a fortress from which to operate in the outside world. For them, their parents seemed more like an obstacle on their way to freedom. . . . All over we heard about the many quarrels going on in families, and the parents had the same complaints: laziness, bored with school, never being home, protest against the slightest coercion (drugs).
''Many classmates of my children moved out on their parents. . . . So parents shy away from using too much pressure, in order to avoid pushing their kids onto a more dangerous path, in order not to lose them.''
After two years the son's graduation approached. ''Discussion about what to do afterwards became hectic. It was pointed out that the central principle of competition and achievement upon which our modern industrial society is built is inhuman and wrong. . . . Some said one should escape. Go to Australia, join a sect, make music. And some thought the radicals were right: 'No one will stop or listen to us before we take to the barricades. We must destroy what destroys us!' ''
For a group of 18-year-olds, the focus of discussion soon became the draft. Seven out of 10 friends wanted to get out of Army duty, for reasons ranging from pacifism to ''better red than dead.''
Graduation came and went. Six months later the parents compared notes.
''One of the loudest voices against the draft, Peter [not his real name], had to join the Army and is serving in a unit nearby. He finds it quite OK. . . . Gunter entered the Navy. As a member of a helicopter crew with rescue missions, he sounds as if the entire northern section of our defense is firm under his crew's control. Lothar, long-haired, do-no-good Lothar is . . . becoming a great pianist and plays already in Army concerts. Two of the boys are studying. One may receive conscientious objector status in the future.
''So it seems that what concerned us so much were just the protesting years of our children,'' she concludes. ''Has not every young generation questioned the world of their parents? Maybe we find it so odd because our protesting years were oppressed by the circumstances of that time (under Hitler). Had we taken the kids too seriously? Or did they reflect, after all, the mood of the young generation?''
Neither the one nor theore consistent than their elders. They are neither heroes nor rogues. They are ordinary people being buffeted by swift change, an unprecedented nuclear threat, and an unprecedented environmental threat. They are reacting, sometimes honorably, sometimes selfishly. As always, they are a threat to the older generations - and a hope as well. Facts on West German youth Population under 21 years: 28 percent Unemployment:
Total: 12 percent
Youth under 20 years: 9.9 percent Education:
Number of students at universities: 1,058,845
Literacy rate: 99 percent
Amount of compulsory education: 10 years Military:
Draft: 15 months
Eligible for draft: men between 18 and 28
Number of conscripts needed each year: 225,000
Registered conscientious objectors as percent of eligible draftees: 10 percent
Backlogged applications for CO status: 90,000
(at December 1982) Source: German Information Center; West German Embassy; Statistical Yearbook of the Federal Republic of Germany Next: Neutrality and reunification with East Germany