157. Psychology. -- Scotus applies to man the same broad pantheistic principles. His teaching on human knowledge and human nature may be summed up as follows

By the exterior sense (sensus exterior) man knows the external sense-world; by the interior sense (sensus interior) he knows the essence throughout its visible or phenomenal realizations; by reason (ratio) he knows the primordial causes of things; by intellect (intellectus) he knows God in His unchanging reality.

Scotus does not seem to have suspected, any more than his contemporaries, the difficulties involved in the problem of the genesis or formation of our knowledge. He recognizes two distinct methods or modes of knowledge: (a) the ascending way, which has its starting-point in sense-experience; and (b) the descending way (gnosticus intuitus), in which the mind, as it advances in knowledge, pursues a path parallel to that of the Divine Substance in its process of auto-formation. Here the cognitive faculty, at first unconscious of itself (intellectus), attains to self-consciousness by representing to itself (ratio) the primordial essences. This representation enables it to apprehend the realized essence (sensus interior) and the external sense-attributes (sensus exterior) of the latter. Human thought is at bottom Divine and follows the evolutions of the Divine Being. Nay more, human knowledge is limitless, for it is God Himself Who thinks in man. The rights of Reason are sovereign both in regard to Nature and to Revelation. Scotus is thus among the most daring of all the medieval rationalists.

Man is a projection of God. The absorption of God in Humanity is asserted with an audacity that is amazing: and this Humanity is of course one with the rest of Nature. By the aid of fanciful interpretations of the Scriptures, Scotus explains the whole Catholic doctrine of the Fall and of Original Sin according to Gnostic theories of symbolism. The transmission of original sin finds an easy explanation in his pantheism (cf. Odo of Toumai).

The body in its original state, "as conceived in its second nature," was free from imperfections. In our present nature we are in a violent and fallen condition (cf. Plato, Plotinus). The return of man to his first state in the bosom of God will be effected by the Redemption through Christ; and since the whole universe shares in the same substance with man, it is through Christ that the final cosmic evolution will be brought about. Thus, for Scotus, Redemption becomes a necessary condition or factor of the evolution of Nature. His teaching about the seven degrees of contemplation and the process of Divine deification, is a strange forcing of the speculations of Pseudo-Denis, and reminds us of the German mysticism of the fifteenth century.