Stanley H. Rosen, 84, of Philadelphia, a scholar and emeritus professor of philosophy, died Sunday, May 4, of pneumonia at Cathedral Village in Roxborough.

Dr. Rosen was an influential writer and teacher known for his thinking and writing on Plato, Heidegger, Hegel, and Nietzsche.

He served on the faculty of Pennsylvania State University for 38 years and Boston University for 14 years before retiring to Philadelphia to be near family.

He was the author of 20 books, recipient of numerous honors, and a former president of the Metaphysical Society of America.

"For those of us who knew him well, his death is a remarkable loss," David Roochnik, chair of Boston University's philosophy department, wrote on the university's website. "He was an extraordinary person and thinker, and we will cherish his memory."

Mr. Rosen was born in Warren, Ohio. The son of Jewish immigrants from Eastern Europe, he went to high school in Cleveland Heights, Ohio.

He earned a bachelor's degree from the University of Chicago in just nine months. Instead of following the college curriculum, he read and wrote. His first book, Death in Egypt, a volume of poetry, came out of that period.

From 1950 to 1955, Dr. Rosen pursued graduate studies in the philosophy department at the University of Chicago.

In 1956, Dr. Rosen joined the philosophy department at Penn State. His family moved to State College.

In 1994, after almost four decades at Penn State, Dr. Rosen joined the Boston University faculty as the Borden Parker Bowne Professor of Philosophy. He spent 14 years there before retiring as emeritus professor in 2008.

As the Etienne Gilson Lecturer for 2003, Dr. Rosen delivered a series of six lectures in Paris. In French, they were published by Presses Universitaires de France.

Dr. Rosen was a prolific writer up until his death. Two volumes of his essays were published in 2013, and another book came out this year. In addition to his books, Dr. Rosen wrote 125 articles and book chapters.

Surviving are his wife of 58 years, Françoise; sons Nicholas D. and Paul M.; a daughter, Valerie R. Wilson; four grandchildren; and two brothers.

Services were private.