Stephen Barker was a distinguished philosopher who served as a professor in the Department of Philosophy at The Ohio State University from 1961 to 1964. During his tenure there, he advised doctoral students, including David Broiles, who earned his Ph.D. in 1963 with the dissertation 'An Analysis of Hume's Arguments Concerning the Role of Reason in Moral Decisions.'

Barker earned his bachelor's degree from Swarthmore College in 1949, a master's degree in philosophy from Harvard University in 1951, and a Ph.D. in philosophy from Harvard University in 1954. His academic career began as an instructor at the University of Southern California from 1954 to 1955, followed by positions as assistant professor and then associate professor at the University of Virginia from 1956 to 1961. After Ohio State University, he joined Johns Hopkins University in 1964 as a full professor, serving until his retirement in 2002 when he was named professor emeritus. He continued to teach in the Krieger School of Arts and Sciences' Advanced Academic Programs for several years. Barker also chaired the Department of Philosophy at Johns Hopkins from 1976 to 1979.

His research specializations included epistemology, philosophy of mathematics, history of modern philosophy, theory of knowledge, applied ethics, philosophy of science, and logic. Barker authored key publications such as Induction and Hypothesis (1957), Philosophy of Mathematics (1964, part of Prentice-Hall's Foundations of Philosophy Series), and The Elements of Logic (1964), a textbook still in use today. He edited or co-edited several other books and published dozens of scholarly articles and reviews.

Barker received major fellowships and honors, including the Sheldon Traveling Fellowship in England (1952–1953), the Santayana Fellowship at Harvard (1955–1956), and the Guggenheim Fellowship (1964–1965). He was a member of the American Philosophical Association, the Hume Society, and the North American Kant Society. Additionally, he served on the editorial boards of Professional Ethics and Essays in Philosophy.