Shortly after President Hosni Mubarak of Egypt was forced from power, radical Islamists, with their long beards and rigid views, joined in street protests in Cairo. That sight quickly stoked the same Western fear that for decades helped justify support for Middle Eastern dictators: Democracy might allow radical Muslims to come to power.

But that perception — still widely held in the West — missed a transformation that was taking place. Those same radical Islamists, who once embraced an ideology that rejected participating in societies they deemed un-Islamic, including their own, were now engaged with their fellow citizenry. Peacefully engaged.

“We believed that the use of violence was the only path to change because every other door was shut to us,” said Gamal El Helali, 49, a member of a once-militant organization, the Islamic Group, who had been jailed for 10 years in Egypt. “The revolution opened the door to peaceful change.”

For the Arab Middle East, few moments in modern history have so clearly marked the end of one era and the start of another as the attacks of Sept. 11, 2001, and the Arab Spring movement of 2011. In fundamental ways, both helped define the image of Muslim Arabs, to themselves and to the world. Both shook the nature of governance, politics and pluralism in the Arab world, and both created an unsettling uncertainty about the future.

But that is where the similarities part.

“When 9/11 took place, the overarching feeling was a feeling of decline, of incapacity to change our situation,” said Amr Hamzawy, a political scientist who is forming a secular, liberal political party in Egypt. “But now it is a different story. We are living up to the challenges and paying the price.”

The Sept. 11 attacks were in part inspired by a radical ideology and belief that the fundamental problems plaguing Arab and Muslim people could be resolved by attacking foreign powers, those propping up dictators, promoting Western culture, oppressing Islam and corrupting civilization.

The Arab Spring has turned that formula inside out, negating premises fundamental to a world that bore and nurtured Osama bin Laden. Arab majorities, still harboring resentment toward Western policies, are first looking inward to promote change, blaming their own leaders for decades of political, economic and cultural decline. There is a degree of societal introspection taking place, one that was pointless in totalitarian societies that discouraged, and often punished, civic participation.

“9/11 is irrelevant right now,” said Tamer Tantawi, 31, an oil company executive in Egypt. “I have much more important issues to be concerned about, like the developments in Egypt, the revolution, what the new constitution will look like, who the next president will be. Domestic affairs have become far more important than 9/11.”

At the same time, the call for change is being advanced — with historic success — primarily by peaceful protests. Though in Libya the uprising escalated to a civil conflict and in Syria thousands of people have been killed by government forces, the successes in Egypt and Tunisia have convinced at least some radical Islamists that they should give the democratic process a chance. The result could ultimately be disorienting to Western notions of stability and security if the revolutions lead to a more Islamist-oriented Middle East — but one that is less violent, at least in terms of its embrace of terrorism to advance a political agenda.

“There is a newfound conviction that protests, strikes and civil action are more effective than fighting and force,” said Marwan Shehadeh, an expert on radical Islamist groups and ideology based in Amman, Jordan.

The Muslim Brotherhood, which long ago disavowed violence, has participated in the political process for years in Jordan and Egypt. But now, Mr. Shehadeh said, those who identify as jihadis, so-called Salafis, are also participating. The result, he said, will force a contest of ideas between the moderates and the radicals who for decades were able to sell their line of thinking to an audience made receptive by repression and the failure of the political process to produce change.

“In Jordan, for example, there is change in the vision and practice of the jihadi Salafis in that they now believe in peaceful action,” he said, acknowledging that the new approach could still be undermined if they fail at the ballot box, or are marginalized by new governments. “They have gone out in several peaceful marches.”

In many ways, the Arab Spring has recast the Arab world from what emerged after 9/11. Paradoxically, the attacks by Al Qaeda helped to reinforce the status quo they were aimed at overturning, giving breathing room to Arab strongmen who relied on fear and repression to preserve their authority. The West continued to subjugate concerns for human rights and democracy to the fear of terrorism.

“We’re talking about two different worlds — one has strengthened the regimes and secret systems and dictatorship and acted exactly contrary to the demands of democracy and freedom,” said Abdulkhaleq Abdullah, a political science professor at United Arab Emirates University. “And the other has fundamentally toppled dictatorships that have been around for decades and has brought the Arab freedom moment, which is the moment we are living.”

The Arab uprisings have recast the region in less tangible ways, too. In terms of identity, Al Qaeda and 9/11 helped transform the Arab into the contemporary bogeyman, with Arabs displacing the Soviets of the cold war era as the prototypical Hollywood villain. Terrorism cemented an image of Arabs as violent, many experts said, and among many Arabs it fostered insecurity and a troubled self-image. When dealing with anyone from the West after the attacks, many Arabs and Muslims said they felt as if they almost always first had to prove a negative, that they were not terrorists.

The Jasmine Revolution, which toppled the Tunisian dictator, Zine el-Abidine Ben Ali, and the subsequent movement that toppled President Mubarak have at least offered an alternative narrative. But as important, the popular uprisings have burnished the self-esteem of many people in the region, offering an antidote to the systemic feelings of inferiority and victimhood, many people said.

“I am not ashamed to say I’m Egyptian today,” said Amgad Shebl, 35, a sound engineer from Cairo. “We were able to gain our respect as a nation.”

And with that rise in self-respect, there is already an expectation, not just that their governments must listen and abide by their views, but also that the West must cast aside stereotypes and preconceptions.

“I think the average Western person must re-evaluate many stereotypes about Arabs,” said Alaa Al Aswany, a best-selling Egyptian author and social critic. “For example, the stereotype that veiled women are helpless or that being veiled means you’re not an independent woman.”

Mr. Aswany said he realized that the Arab Spring was the opposing bookend to the Sept. 11 attacks not long ago, during a weekly salon he holds in Cairo. His French translator, Gilles Gauthier, approached him. “Osama bin Laden,” the translator told Mr. Aswany, “did not die yesterday, but he was killed on the 25th of January.”

That was the day the Egyptian revolution began.