extended work, De Concordantia Catholica, which he had completed at Basle. In 1440 (having already written on the Reform of the Calendar) he began his imposing series of philosophical writings with the De Docta Ignorantia, to which the De Conjecturis was added in the following year. These were succeeded by smaller treatises entitled De Quaerendo Deum, De Dato Patris Luminum, De Filiatione Dei, De Genesi, and a defense of the De Docta Ignorantia. His most important work is the third of the four dialogues of the Idiota ("On the Mind"), 1450. He clothes in continually changing forms the one supreme truth on which all depends, and which cannot be expressed in intelligible language but only comprehended by living intuition. In many different ways he endeavors to lead the reader on to a vision of the inexpressible, or to draw him up to it, and to develop fruitfully the principle of the coincidence of opposites, which had dawned upon him on his return journey from Constantinople (De Visione Dei, Dialogus de Possest, De Beryllo, De Ludo Globi, De Venatione Sapientiae, De Apice Theoriae, Compendium). Sometimes he uses dialectical reasoning; sometimes he soars in mystical exaltation; sometimes he writes with a simplicity level to the common mind, and in connection with that which lies at hand; sometimes, with the most comprehensive brevity. Besides these his philosophico-religious works are of great value, De Pace Fidei, De Cribratione Alchorani. Liberal Catholics reverence him as one of the deepest thinkers of the Church; but the fame of Giordano Bruno, a more brilliant but much less original figure, has hitherto stood in the way of the general recognition of his great importance for modern philosophy.
Human knowledge and the relation of God to the world are the two poles of the Cusan's system. He distinguishes four stages of knowledge. Lowest of all stands sense (together with imagination), which yields only confused images; next above, the understanding (ratio), whose functions comprise analysis, the positing of time and space, numerical operations, and denomination, and which keeps the opposites distinct under the law of contradiction; third, the speculative reason (intellectus), which finds the opposites reconcilable;
