BEIRUT, Lebanon — In his first address in two months, President Bashar al-Assad of Syria on Monday offered a national dialogue that he said could usher in change to a country where his party and family have monopolized authority for four decades.

Deep skepticism greeted the proposal, and even some who were sympathetic to the leadership said they doubted that Mr. Assad was ready to surrender absolute power, at least for now. But as the country wrestles with its gravest crisis in a generation, the question remains: If the government is in fact sincere, whom would it talk to?

An opposition abroad, without set leaders or programs, which sought to organize in meetings in Turkey and Europe, has ruled out engaging the government. Many activists who claim to speak for those in the streets shaken by three months of protests are too afraid to surface. Even opposition figures in Damascus who have talked with officials lately said Monday that they would not attend the dialogue Mr. Assad outlined until security forces ended their crackdown.

The government, which long equated almost any dissent with sedition, has suggested it may choose whom it will speak to; Mr. Assad mentioned the possibility of more than 100 people, though the government has yet to say who they may be.