Anselm's Discovery: A Re-Examination of the Ontological Proof for God's Existence

Did Anselm, in his Ontological Argument (first advanced around 1070), make one of the greatest intellectual discoveries of all time, or did he merely fall into an interesting blunder?
In his day, Anselm was criticized by Gaunilo. Subsequent philosophers have generally considered Gaunilo’s criticisms to be weighty. Descartes’s attempt to resuscitate Anselm’s argument led to Kant's supposed refutation, which most later philosophers have considered to be fundamentally sound.
Charles Hartshorne has done more than any other writer to bring back the Ontological Argument as a major problem of modern philosophical analysis, and Anselm’s Discovery is his most systematic exposition of the history of the subject. According to Hartshorne, generations of philosophers have read Anselm superficially, and have failed to see that Anselm presented two forms of the Argument, the second involving a genuine conceptual breakthrough.
Charles Hartshorne is the author of A Natural Theology for Our Time and The Logic of Perfection. He is the subject of and leading contributor to Volume XX of The Library of Living Philosophers, The Philosophy of Charles Hartshorne, edited by Lewis
E. Hahn.