Gaunilo : Also Gaunilón or Gaunillon . Benedictine monk of Marmoutier Abbey in Tours in the 11th century, known because in his writing "In the Name of the Fool" he was the first to criticize st. Ansemo's ontological argument about the existence of God. This did not mean that he defended atheism, but that St. Anselmo's argument had no logical rigor.