why can only humans attain moksh

In Jainism, moksha (liberation) is the soul’s release from all karmic bondage. The key point is not which species or beings can become free, but how a soul purifies itself of karma and diminishes craving and ignorance.

What actually makes moksha possible

• A soul attains moksha by shedding all karmas through right belief (samyak darshan), right knowledge (samyak jnana), and right conduct (samyak charitra), along with sustained practice such as disciplined ethics, meditation, nonviolence, and austerities.
• Once all karmas are shed, the soul rises to the pure immortal realm of siddhas (liberated beings) and remains there free from the cycle of birth and death.

Is it true that only humans can attain moksha?

• Jain teaching emphasizes that human birth is especially conducive to moksha because it provides the right conditions to practice the three gems (samyak darshan, jnana, charitra) and to perform the strenuous austerities needed to purge karma.
• However, moksha is not restricted to humans in a absolute sense. A soul can, in principle, become liberated from any life-form if it accumulates the right purity and discipline and sheds all karmas. In practice, human birth is considered the most favorable and reliable vehicle for achieving this, which is why most liberated souls are said to have gone through a human life.

What about the role of women, and differences between Digambara and Śvetāmbara views?

• Digambara and Śvetāmbara traditions differ on the question of whether women can attain kevala jñāna (omniscience) and moksha. Śvetāmbara sources generally hold that women can attain liberation (though they may need rebirth in a human form to complete certain spiritual steps). Digambara sources traditionally emphasize that a male body is required to attain kevala jñāna and moksha, implying women must take birth as men to reach the final stage.
• Both traditions agree that liberation is possible for those who purify their souls and adhere to correct conduct; they simply differ in details of the path and the gendered prerequisites in their canonical interpretations.

In short

• Moksha is possible for any jiva who completely purifies itself of karma through right faith, right knowledge, and right conduct.
• Human life is especially favorable for achieving that purification, which is why Jain teachings say humans have the best chance to become liberated.
• There are doctrinal differences between Digambara and Śvetāmbara regarding gender and the precise prerequisites for final liberation.

If you’d like, I can explain specific sutras or stutis that discuss moksha in more detail, and note how Digambara and Śvetāmbara viewpoints differ on those texts.