He was a visiting professor at the University of Minnesota, the University of Cape Town, the University of California at Los Angeles, Princeton University, and Yale University. A former Phi Beta Kappa National Lecturer, he delivered the Cardinal Mercier Lecturer at the (Flemish) University of Leuven in 1995 and the Reynolds Lecture at Baylor University in 2005. He also served on numerous scholarly committees and congresses worldwide and is the only person ever to have been elected president of all the following professional organizations: the American Philosophical Association (1984), the Philosophy of Science Association, the Metaphysical Society of America (1974) and the American Catholic Philosophical Association. He served as the chair of the History and Philosophy of Science Section of the AAAS, as a member of the executive committees of the History of Science Society, the Council for Philosophical Studies, and the Society of Christian Philosophers, and as a member of numerous scholarly and scientific committees, congresses, and panels. A fellow of the American Academy of Arts and Sciences, the International Academy of the History of Science, and the AAAS, he was an honorary fellow of St. Edmund's College, Cambridge, and was awarded honorary degrees by the National University of Ireland at Maynooth, Loyola University (Chicago), Stonehill College, and University of Notre Dame.