Jivastikaya is the psychic order of existence and cetana or consciousness is its chief characteristic. Individual jiva is the SELF, ultimatic Reality of which is self-evident. It is the central conception of Jain thought.
Life and consciousness are co-extensive. Wherever there is life, there is consciousness, and the vice versa, But there are degrees of explicitness or manifestations of cetana in different organisms. In the lowest class of organisms, it is very much latent; while in human beings, it is very much manifest. It is entirely distinct from all inanimate existence.
Characteristic qualities viz. colour, odour, etc. inherent in physical existence have no relevance in the case of jiva, and hence, it cannot be cognised by sense-perception.
Cetana manifests itself in several ways: intuition, perception (cognitive elements), emotions, will, attitude and behaviour, awareness of pleasure and pain.