The central concept of Jaina psychology is jīva (self), a living organism, a biological being, a conjoint psycho-somatic, psycho-physical, conscious entity. Every organism is an organic unity of two distinct entities jīva and pudgal (matter), soul and body. The two are distinct entities because the nature of consciousness or soul is radically different from matter and the two entities have opposite qualities. Jīva or soul is sentient, non-corporeal, conscious entity, possessing subjective attributes of cognition, feeling and volition, while matter or body is non-sentient, corporeal, inanimate entity possessing characteristic sense qualities of touch, taste, smell and colour.
Although quite a number of scientists in the West tend to make a distinction between self and non-self based on body/non-body distinction, their framework and conception differ in important respects from Jaina thought. Thus, Gerald Edelman's “biological individuality” and Antonio Damasio's “conscious self” are not quite the same as Jaina conscious entity. Damasio's so-called “conscious self” or “core consciousness” is merely “the critical biological function” or “organism's private mind” which together with its external behaviour is said to be “closely correlated with the functions….of the brain” (Damasio, 1999, pp. 12–13,15,347). According to Jainism, the nature of Jīva is chetanā (sentiency or consciousness). Life and consciousness are co-extensive. Wherever there is life, there is consciousness. Even in the lowest class of organisms, we have to posit existence of a certain degree of consciousness, howsoever latent or implicit it might be. The inner, subjective, qualitative, spiritual reality of jīva is consciousness, also called soul, while the physical, objective, external manifestations of jīva are known as dravya praṇas (the physical insignia of life).