Kevala jnana, "isolated" or absolute knowledge, is omniscience in Jain teaching: direct, simultaneous and complete knowledge of all substances in all their modes, past, present and future. It is not an addition to the soul but the soul's own nature, uncovered when the four destructive karmas are destroyed. One who attains it is a kevalin; a kevalin who also teaches and establishes the fourfold community is a Tirthankara.
Because knowledge is the soul's nature rather than an achievement, the Jain account differs from omniscience as discussed in other Indian schools: it is not an inference about a supreme being but a claim about what any soul is when unobstructed. It also does foundational work, since Jain scripture derives its authority from having been spoken by omniscient beings, and it supplies the standing answer to the charge that syadvada makes Jainism relativist, the kevalin's knowledge is unqualified, and qualification belongs only to the partial knowledge of everyone else.
After attaining kevala jnana a person continues to live until the remaining non-destructive karmas are exhausted, and the condition of such a being is analysed carefully. Whether a kevalin still requires food, and whether ordinary bodily functions continue, is one of the questions on which the two great Jain communities divide.
The Digambara position holds that the kevalin no longer takes food or engages in bodily functions, being sustained without them, on the ground that omniscience is incompatible with such dependence. Digambaras also hold that complete nudity is required for the highest ascetic practice, and therefore that liberation is not possible in a female body, so that a woman must first be reborn as a man.
The Svetambara position holds that the kevalin continues to eat and to function bodily, on the ground that embodiment entails such needs and that omniscience concerns knowledge rather than physiology. Svetambaras hold that women can attain liberation directly, and their tradition maintains that the nineteenth Tirthankara, Malli, was a woman, a claim Digambaras reject, holding Malli to have been male.
These are not marginal disagreements. They are the principal doctrinal markers separating the two communities, they are bound up with the question of whether any clothing at all is compatible with complete non-possession, and the disagreement about women's capacity for liberation is among the most substantive in the tradition. Both communities agree entirely that the kevalin's knowledge is complete and that omniscience is the goal.