Man is a ‘thinking animal.’ Once his animal needs are satisfied and he obtains relative peace and stability in life, he starts thinking about the ‘how,’ the ‘why’ and the ‘when’ of things perceived. This thinking about the origin and evolution of things has got to be in the form of conjectures and hypotheses before being advanced as theories. Such conjectures and hypotheses again, can start only from the seen and the known before progressing towards the unseen and the unknown. It is but natural that this world in which man lives, moves and has his being (as it were), is the first to catch his attention. Such attention and thinking often leads to a broad categorisation of the created world. Of such categorisations, what can be more simple, direct and obvious than the twofold one, viz., the living and the non-living, the sentient and the non-sentient? This is exactly what the Viśiṣṭādvaita Vedānta system—of which Rāmānuja (A. D. 1017-1137) is the chief exponent—has done.
According to this system, the ultimate Reality is threefold: cit (the sentient), acit (the insentient) and Īśvara (God). The former two are dependent realities, subservient to the latter. (For details see VIŚIṢṬĀDVAITA VEDĀNTA DARŚANA.)
The acit principle, as its very name indicates, is the matrix of all that is without life and consciousness. Also called prakṛti (nature), it is jaḍa (lifeless and insentient) but capable of vikāra (modi-fication or evolution). It is avidyā (ignorance) since it is opposed to true knowledge and also called māyā since it is the cause of all diverse creations. Being insentient it is incapable of evolving by itself but does so under the controlling will of God.
According to one classification this acit has three aspects: the śuddha-sattva, the miśra-sattva and sattva-śūnya. The śuddha-sattva aspect has pure sattva guṇa (See GUṆAS.) capable of producing knowledge and bliss, and is the matrix out of which the world Vaikuṇṭha (See VAIKUṆṬHA.) has been made. It is un-affected by the karma of the individual souls and is directly under the control of God. The miśra-sattva aspect has the three guṇas of sattva, rajas and tamas. It is this which evolves as this world, contracts and obstructs the jñāna (knowledge) of the jīvas (individual selves) and sustains their bondage by producing viparīta-jñāna (knowledge opposed to their real nature). Kāla or time forms the third aspect viz., sattva-śūnya.
Whether kāla should be deemed as an aspect of acit or considered as a special power inhering in God has been a point of debate among the thinkers of the Viśiṣṭādvaita school.