The mixture of political flexibility and moral certainty, of high-minded rhetoric delivered with infectious urgency, is the trademark of this man who, perhaps better than any of his peers, has managed to combine the roles of intellectual and activist in a communist-ruled country.

In the West, Michnik's reputation has grown in recent years as one of Europe's most original political thinkers, a formulator and principal defender of the nonviolent resistance to totalitarianism embodied in the banned Solidarity union.

In Poland, meanwhile, this naturally gregarious figure remains a dynamo of opposition organization: a spokesman, adviser, instigator and coordinator. He seems to spend many of his days rushing from political meetings to briefings with diplomats to underground encounters with clandestine printers and publishers.

"I consider my writing as one form of my activism," Michnik said in an interview this week. "As for the rest of what I do," he added with characteristic playfulness, "that is something the Polish police would pay a lot of dollars to know about."

Even by Michnik's standards, this week has been exceptional. On Tuesday, he lunched with Belgian Foreign Minister Leo Tindemans, who was paying an official visit to Poland. Today, he met with a delegation of trade union leaders from Chile who traveled to Poland on tourist visas to compare notes on opposition to dictatorship.

On Friday, Michnik and former Solidarity underground leader Zbigniew Bujak are due to be presented with the Robert F. Kennedy Human Rights Award by Sen. Edward M. Kennedy (D-Mass.) in a private ceremony here. They have accepted the $ 40,000 award as a recognition of the continuing importance of Solidarity's existence and its nonviolent philosophy.