The speculative faculties are the choicest of all the powers of the Soul. Acquaintance with the world is conveyed to the rational soul by the External and Internal Senses. In particular a full account is given by Ibn Sina of his theory of the Internal Senses, or the sensuous-spiritual faculties of representation, which have their seat in the brain.
Medical Philosophers commonly assumed three Internal Senses or stages of the representative process: 1. Gathering the several sense-perceptions into one collective image in the fore part of the brain; 2. Transforming or remodelling this representation of the general Sense, with the help of representations already existing, thus constituting apperception proper, in the middle region; 3. Storing up the ‘apperceived’ representation in the Memory, which was held to reside in the hinder part of the brain. Ibn Sina, however, carries the analysis somewhat farther. He distinguishes in the anterior portion of the brain the Memory of the Sensible,—or the treasure-house of the collective images,—from the General or Co-ordinating Sense. Farther, he makes out Apperception,—the function of the middle region of the brain,—to be in part brought about unconsciously, [[141]]under the influence of the sensible and appetent life, as is the case also with the lower animals, and, on the other hand, to take place in part consciously, with the co-operation of the Reason. In the first case the representation preserves its reference to the individual thing,—thus the sheep knows the hostility of the wolf,—but in the second case, the representation is extended to the Universal. Then, in the hinder part of the brain, the Representative Memory, or store-house of the representations formed by combined Sensuous Impression and Rational Reflection, follows as a fifth power. In this way five Internal Senses[4] correspond to the five External Senses, although with quite another reference than the five Internal Senses of the Faithful Brethren. The question which is raised—as to whether one should farther separate Recollection, as a special faculty, from Memory,—remains unanswered.
6. At the apex of the intellectual powers of the Soul stands the Reason. There is indeed a Practical Reason also, but in its action we have been only multiplying ourselves mediately: On the other hand, in Self-Consciousness, or the pure recognition of our essential nature, the unity of our Reason is directly exhibited. But instead of keeping down the lower powers of the Soul, the Reason lifts them up, refining Sense-Perception, and generalizing Presentation. Reason, which at first is a mere capacity for Thought, becomes elaborated gradually,—in that Material which [[142]]is conveyed to it by the external and internal senses,—into a finished readiness in Thought. Through exercise the capability becomes reality. This comes about through the instrumentality of experience, but under guidance and enlightenment from above,—from the ‘Giver of the Forms’, who as Active Spirit imparts the Ideas to the Reason. The Soul of man, however, does not possess any memory for the pure ideas of Reason, for memory always presupposes a corporeal substratum. As often then as the Rational Soul comes to know anything, that knowledge flows to it on each occasion from above; and thinking Souls do not differ in the range and contents of their knowledge, but in the readiness with which they put themselves in communication with the Spirit over us, in order to receive their knowledge.
The Rational Soul, which rules over that which is under it, and comes to know the higher by means of the enlightenment given by the World-Spirit, is then the real Man,—brought into existence, but as unmixed essence, as individual substance, indestructible, immortal. On this point the clearness of Ibn Sina’s teaching marks it off from that of Farabi; and, since his time, the assumption of the individual immortality of the human Souls, which have come into being, is regarded in the East as Aristotelian, and the opposite doctrine as Platonic. Thus a better understanding prevails between his philosophy and the accepted religion. The human body and the whole world of sense furnish the Soul with a school for its training. But after the death of the body, which puts an end to this body for ever, the Soul continues to exist in a more or less close connection with the World-Spirit. In this union with the [[143]]Spirit over us,—which is not to be conceived as a complete unification,—the blessedness of the good, ‘knowing’ souls consists. The lot of the others is eternal misery; for just as bodily defects lead to disease, so punishment is the necessary consequence of an evil condition of Soul. In the same way too, the rewards of Heaven are apportioned according to the degree of soundness or rationality which the Soul has attained in its life on earth. The pure Soul is comforted amidst the sufferings of Time by its prospect of Eternity.
The highest is of course, reached only by a few; for on the pinnacle of Truth there is no room for the many; but one presses forward after another, to reach the source of the knowledge of God, welling forth on its lonely height.
7. To express his view of the Human Reason, Ibn Sina employs and explains poetical traditions,—a favourite proceeding in the Persian literature. First and foremost our interest is awakened by the allegorical figure of Hai ibn Yaqzan. It represents the ascent of the Spirit out of the Elements, and through the realms of Nature, of the Souls, and of the Spirits, up to the throne of the Eternal One. Hai presents himself to the philosopher in the form of an old man with an air of youth about him, and offers his services as guide. The wanderer has been striving to reach a knowledge of Earth and Heaven, by means of his outer and inner senses. Two ways open out before him, one to the West, the way of the Material and the Evil, the other to the Rising Sun, the way of Spiritual and ever-pure Forms; and along that way Hai now conducts him. Together they reach the well of Divine wisdom, the fountain of everlasting youth, where beauty is the curtain of beauty, and light the veil of light,—the Eternal Mystery. [[144]]
Hai ibn Yaqzan is thus the guide of individual, thinking Souls: he is the Eternal Spirit who is over mankind, and operates in them.
A similar meaning is found by our philosopher in the frequently remodelled late-Greek legend of the brothers Salaman and Absal. Salaman is the World-Man, whose wife (i.e., the World of the Senses) falls in love with Absal, and contrives by a stratagem to wile him into her arms. But before the decisive moment, a flash of lightning comes down from heaven, and reveals to Absal the wantonness of the action which he had nearly committed, and raises him from the world of sensual enjoyment to that of pure spiritual contemplation.
In another passage the soul of the philosopher is compared to a bird, which with great trouble escapes from the snares of the earth, traversing space in its flight, until the Angel of Death delivers it from the last of its fetters.
That is Ibn Sina’s Mysticism. His soul has needs, for which his medicine-chest provides no resource, and which the life of a court cannot satisfy.