Under sunny skies, the University of Pennsylvania celebrated its 251st commencement yesterday.

About 6,000 people received degrees at the Franklin Field ceremony. Among them was commencement speaker James A. Baker 3d, the former secretary of state and cochairman of the Iraq Study Group. He was given an honorary doctor of law degree.

The singer and songwriter Aretha Franklin, U.S. Supreme Court Justice Ruth Bader Ginsberg, and Atlanta Mayor Shirley Franklin also were given honorary degrees.

Also honored at yesterday's ceremony were Penn professor emeritus Aaron Temkin Black, director of the Center for the Treatment and Prevention of Suicide; Caroline W. Bynum, a professor of European medieval history at Princeton University; and Mildred Dresselhaus, a professor of electrical engineering and physics at Massachusetts Institute of Technology.