Bobby Yip/Reuters

GUANGZHOU, China — For two decades after the Tiananmen Square crackdown in 1989, China seemed on the surface like a country where free-market and even laissez-faire principles prevailed. It looked as if a consensus had been reached on putting economic policy and the headlong pursuit of affluence ahead of ideology and politics.

That appearance of consensus, which in fact had always masked some internal divisions in the Communist Party and in Chinese society at large, is now breaking down. The question is whether this will lead to greater political openness, an authoritarian clampdown to restore the veneer of stability, or social turmoil — all possibilities that could have hard-to-predict consequences for the country’s economic expansion, and for the world’s.

The unraveling has been visible in several ways, including the large environmental protests that have occurred in nearly a dozen Chinese cities over the last year and a half. Tens of thousands of residents of each of those cities, including Dalian and Tianjin, have turned out in successful efforts to block the construction of chemical factories, smelters and power plants, as fears of pollution outweigh the promise of job creation.

The breakdown was also apparent in September, when thousands of demonstrators carried large portraits of Mao past the Japanese embassy in Beijing as tension between China and Japan mounted over disputed islands near Taiwan.

The protesters’ choice of Mao posters conveyed an undercurrent of criticism of the country’s present leaders, who conspicuously omit Mao and his collectivist ideology from most speeches these days.

And even more recently, the breakdown of the consensus was evident during four days of protests over free speech this month outside the offices here of the most famous crusading newspaper in China, Southern Weekend, also known as Southern Weekly.

The journalists were calling for the removal of a provincial propaganda chief who had rewritten a New Year’s editorial, contorting an anguished review of social troubles into a paean to the accomplishments of the Communist Party.

“It is very clear that the kind of willingness that has been there, in the name of economic growth, to brush everything under the carpet is now gone,” said Odd Arne Westad, a professor of international history at the London School of Economics.

While the police peacefully persuaded demonstrators to go home on the fourth day, it was significant that the protest lasted as long as it did.

“People were standing on the podium saying, ‘press freedom, press freedom,’ and the police did not drag them down — it shows that the police in dealing with societal conflict now respect the right of free speech, and it is a new evolution that the people feel they have the right of free speech,” said Yuan Weishi, a retired historian at Sun Yat-Sen University in Guangzhou who is also one of the best-known liberal intellectuals in southern China.

Clutching several placards covered with slogans in Chinese characters, a short-haired young man in a brown jacket bravely hovered near the newspaper’s driveway through the fourth day of the protest, despite police efforts to persuade him to leave. As police officers formed a human wall that moved back and forth to prevent him from walking over to talk to a foreign journalist, he yelled over their shoulders, “The police have no right to prevent me from speaking to anyone.”

While the Chinese Constitution guarantees freedom of speech, that freedom has only infrequently been permitted on a broad scale since the founding of the Communist state in 1949, and seldom in the centuries before that. But the growing perception that the freedom exists or should exist, particularly among young people accustomed to fairly freewheeling discussions on the Internet, suggests a fundamental shift in Chinese society.

Equally important is that young people in China today increasingly seem to feel not only that they have a right to speak out, but also that they have a responsibility to air social problems.

Mr. Westad, who was living in China before, during and immediately after the Tiananmen Square killings, noted that among the young, this sense of personal responsibility in addressing social ills in a public way was last apparent in the 1980s, before nearly disappearing in the subsequent repression and amid the “get rich quick” mentality that later emerged.

What is far less clear is whether the emerging, faint hints of pluralism in China can produce a new social consensus and perhaps even a few tentative steps toward democracy. The question is whether the dialogue will someday produce something like the Arab Spring, which Vali R. Nasr, dean of the Paul H. Nitze School of Advanced International Studies at Johns Hopkins University, describes as a series of headless revolutions — hard to decapitate, but also hard to guide, control or predict.

Sharp, conflicting divisions about China’s future were visible at the Southern Weekend protests, and could someday prove to have been an early warning of social schism.

On one side of the newspaper’s driveway were a dozen self-appointed advocates of some combination of stricter authoritarianism, anti-Western nationalism and economic isolationism. These demonstrators, representatives of a “new left” group called Utopia, castigated the newspaper’s journalists as unpatriotic. They also denounced a list of culprits that might have been lifted from a far-right blog in the West, claiming an international conspiracy of financiers, the media and the United States government.

Yet more numerous and more noisy on the other side of the driveway were the free-speech protesters, mostly young journalists and their local supporters, who also received heavy support in Chinese Internet postings. They showed personal courage in assailing a senior censor, a daring that is becoming increasingly common in China as more and more people start standing up to the authorities and often suffer few penalties for doing so — except if they call for a multiparty democracy or a review of the Tiananmen Square killings.

The advocates of greater political openness may have time on their side. Utopia demonstrators tend to be middle-aged, part of a generation whose early education was stunted by the Cultural Revolution when many schools and universities effectively closed.

The free-speech demonstrators were considerably younger and far better educated, beneficiaries of China’s huge expansion of higher education in recent years.

The educated youth of China also seem less inclined for now to support aggressively nationalistic policies toward China’s neighbors, professors and young people say. College students were numerous in a previous round of anti-Japanese protests in 2005, particularly in Guangzhou. But Japanese fashions and popular entertainment have become much more popular among young Chinese since then.

The rioters who overturned and destroyed about 100 Japanese-brand cars during demonstrations in major Chinese cities in September, before a more peaceful march in Beijing, tended to be predominantly older, blue-collar workers.

Mr. Yuan, the historian, said he perceived an evolution in the thinking of the country’s elite. “The mind-set is changing, all the way from the central government to local officials,” he said.