These processes, however, are nothing more than so many manifestations of love. Assimilation indicates attraction and transformation of what is external into what is internal. Growth is love of achieving more and more harmony of parts; and reproduction means perpetuation of the kind, which is only another phase of love. 3. In the animal kingdom, the various operations of the force of love are still more unified. It does preserve the vegetable instinct of acting in different directions; but there is also the development of temperament which is a step towards more unified activity. In man this tendency towards unification manifests itself in self-consciousness. The same force of "natural or constitutional love", is working in the life of beings higher than man. All things are moving towards the first Beloved--the Eternal Beauty. The worth of a thing is decided by its nearness to or distance from, this ultimate principle. As a physician, however, Avicenna is especially interested in the nature of the Soul. In his times, moreover, the doctrine of metempsychosis was getting more and more popular. He, therefore, discusses the nature of the soul, with a view to show the falsity of this doctrine. It is difficult, he says, to define the soul; since it manifests different powers and tendencies in different planes of being. His view of the various powers of the soul can be thus represented:-- 1. Manifestation as unconscious activity-- (a). Working in different directions ┌ 1. Assimilation. (Vegetative soul) │ 2. Growth. └ 3. Reproduction. (b). Working in one direction and securing uniformity of action--growth of temperament. 2. Manifestation as conscious activity-- (a). As directed to more than one object-- Animal soul. │ ┌────────────┴────────────────────┐ │ │ Lower Animals. Man. A. Perceptive powers. A. Perceptive powers. B. Motive powers (desire (a) Five external senses. of pleasure and avoidance (b) Five internal senses-- of pain). 1. Sensorium. 2. Retention of images. 3. Conception. 4. Imagination. 5. Memory. These constitute the five internal senses of the soul which, in man, manifests itself as progressive reason, developing from human to angelic and prophetic reason. B. Motive powers--will. (b). As directed to one object--The soul of the spheres which continue in one uniform motion.