This oneness of the active intellect, or reason, is the essential principle of the Averroistic theory, and is in harmony with the cardinal doctrine of Mohammedanism the unity of God. The individual, or passive, or subjective intellect, is an emanation from the universal, and constitutes what is termed the soul of man.
Aristotelianism, introduced by Alfarabi, Avicenna and Averroes among the Arabs, and Ibn Daud and Maimonides among the Jews, dominated all speculative thought, and the old Kalam was obsolete and forgotten. Gersonides no longer regards the Kalamistic point of view as a living issue. He ignores it entirely. His problems as we have seen are those raised by the Averroistic system.
The indignation of that saint knew no bounds when Christians became the disciples of an infidel, who was worse than a Mohammedan. The wrath of the Dominicans, the order to which St. Thomas belonged, was sharpened by the fact that their rivals, the Franciscans, inclined to Averroistic views; and Dante, who leaned to the Dominicans, denounced Averroes as the author of a most dangerous system.
A similar accusation, as is well known, was brought against the primitive Christians by the fashionable society of Rome. The influences of the Averroistic philosophy were apparent in many of these sects.
The latter insisted on the unity of the intellect for the human race, thereby destroying individual immortality, and this Averroistic doctrine, adopted by some Masters of Arts at the University of Paris, was condemned among other heresies, and refuted in the writings of Albertus Magnus and Thomas Aquinas. Maimonides does not discuss these problems in detail in his "Guide."