Alexander Robert Pruss (born January 5, 1973) is a Canadian philosopher, mathematician, Professor of Philosophy and the Co-Director of Graduate Studies in Philosophy at Baylor University in Waco, Texas. His best known book is The Principle of Sufficient Reason: A Reassessment (2006). He is also the author of the books, Actuality, Possibility and Worlds (2011), and One Body: An Essay in Christian Sexual Ethics (2012), and a number of academic papers on religion and theology. He maintains his own philosophy blog and contributed to the Prosblogion philosophy of religion blog.