The concept of soul or Atman has been one of the fundamental doctrines of almost all Indian philosophies. Some of the Indian schools treat Atman as the Primordial element of the universe. According to them, the whole cosmos has emerged from one entity i.e. the Supreme Being (Paramātman or Brahman). The Jain philosophy regards that the world of our experience is either a living entity or the entities left by the living ones. It is, according to Jainism, because earth, water, air, fire etc. are not devoid of consciousness.
Jain philosophy describes conscious substance from several points of view, such as, metaphysical, cosmological, spiritual, psychological and biological, etc. In Jainism, due to this multi-dimensional character of conscious substance many important theories have come into being. All of them cannot be dealt with within one chapter. In present work only a few biological issues have been taken-up. Besides, some important concepts that had been longstanding problems before the Eastern and Western philosophy as well as Psychology, have been discussed with reference to the Bh.S in particular.