A Philosophically Conservative Rejoinder to What Is Marriage? What Is Marriage? Man and Woman: A Defense, authored by Ryan T. Anderson, Robert George, and Sherif Girgis, is widely recommended as the foremost defense of “one man/one woman” marriage based on natural law principles. The book has undoubtedly been influential, even to the point of being cited by Supreme Court Justice Samuel Alito in his United States v. Windsor dissent. Significantly, the book does not rely