Ferdinand Ulrich (1931-2020) was a German Catholic philosopher and professor at the University of Regensburg. Andrew Shivone is President of St. Jerome Institute, Washington, DC. Robert Van Alstyne, SJ, is a priest of the USA West Province of the Society of Jesus and a doctoral candidate in philosophy at Boston College. D.C. Schindler is professor of metaphysics and anthropology at Pontifical John Paul II Institute for Studies on Marriage and Family, Washington D.C.