In the Tattvartha Sutra, jīva is presented as the conscious principle, the sentient substance whose defining mark is upayoga, the activity of awareness. It is eternal and distinct from matter, not composed of physical atoms, yet it undergoes changing modes due to its association with karma. By its very nature it possesses consciousness and the potential for liberation, and in its pure state it is said to have unobstructed knowledge, perception, bliss, and power. Worldly experience—pleasure and pain, delusion and clarity—arises as this conscious substance becomes bound with karmic matter.

From this perspective, all living beings are manifestations of jīva, and the Sutra classifies them in several interrelated ways. A fundamental division is between bound souls (baddha or saṃsārī jīva), which are enmeshed in karma and subject to birth and death, and liberated souls (mukta or siddha jīva), which are completely free from karmic bondage. Liberated jīvas no longer transmigrate and abide in a perfected state, possessing unobstructed knowledge, perception, bliss, and power, while bound jīvas continue to wander through various forms of existence.

Among bound souls, one of the most prominent classifications is by the number of senses. One-sensed beings (ekendriya) possess only touch and include earth-bodied, water-bodied, fire-bodied, air-bodied, and plant-bodied lives. Two-sensed beings (dvi- or dvindriya) have touch and taste; three-sensed beings (trindriya) add smell; four-sensed beings (chaturindriya) add sight; and five-sensed beings (pañcendriya) possess all five senses. Humans, many animals, celestial beings, and hell beings fall into the five-sensed category, though their spiritual condition may differ greatly.

The Sutra further refines this picture through classifications by mobility, mind, birth, and realm. Immobile beings (sthāvara) are one-sensed, while mobile beings (trasa) possess two to five senses. Some beings are described as endowed with mind (samanaska), having a rational or deliberative faculty, while others are without mind (amanaska), acting more instinctively. Birth itself is analyzed into types such as womb-born, egg-born, sprouting, and spontaneous generation, and five-sensed beings are also grouped by realm as humans, animals and other non-human creatures, celestial beings, and hell beings.

Taken together, these classifications show a vision in which the same fundamental reality—conscious jīva—appears in a vast spectrum of embodiments and capacities. Every soul, whether one-sensed or five-sensed, mobile or immobile, rational or instinctive, shares the same essential nature and the same ultimate potential for liberation. The intricate taxonomy of living beings thus serves not merely as a catalog of life-forms, but as a map of the many conditions through which consciousness journeys while obscured by karma, and from which it may ultimately emerge free.