Descartes, in the Meditations (1641), notes that "there are only two ways of proving the existence of God, one by means of his effects, and the other by means of his nature or essence.” (AT VII, 120). The latter, a priori path, represented paradigmatically by the Ontological Argument of Saint Anselm (and its offspring, including Descartes’s own version), has perennial appeal to a certain sort o...