and posterior non-existence (which we should respectively call future and past existence), mutual non-existence (as between a jar and cloth), and absolute non-existence (as fire in water).
Though largely concerned with these categories, the Vaiçeshika system aimed at attaining a comprehensive philosophic view in connection with them. Thus while dealing with the category of "substance," it develops its theory of the origin of the world from atoms. The consideration of the category of "quality" similarly leads to its treatment of psychology, which is remarkable and has analogies with that of the Sānkhya. Soul is here regarded as without beginning or end, and all-pervading, subject to the limitations of neither time nor space. Intimately connected with soul is "mind" (manas), the internal organ of thought, which alone enables the soul to know not only external objects but its own qualities. As this organ is, in contrast with soul, an atom, it can only comprehend a single object at any given moment. This is the explanation why the soul cannot be conscious of all objects simultaneously.
The Nyāya system is only a development and complement of that of Kaṇāda, its metaphysics and psychology being the same. Its specific character consists in its being a very detailed and acute exposition of formal logic. As such it has remained the foundation of philosophical studies in India down to the present day. Besides dealing fully with the means of knowledge, which it states to be perception, inference, analogy, and trustworthy evidence, it treats exhaustively of syllogisms and fallacies. It is interesting to note that the Indian mind here independently arrived at an exposition of the syllogism as the form of deductive reasoning. The
