Answer

Jains came to know about very tiny living beings through the teachings of the Tirthankars, especially Bhagwan Mahavir, and through deep spiritual knowledge described in Jain scriptures.

Jain Dharma has taught for a very long time that life exists not only in humans, animals, birds, and insects, but also in extremely small beings that ordinary eyes cannot see.

Explanation

In Jain philosophy, living beings are classified in many ways. One important classification is according to the number of senses:

• One-sensed beings such as earth-bodied, water-bodied, fire-bodied, air-bodied, and plant-bodied beings
• Two-sensed to five-sensed beings such as worms, insects, animals, humans, and heavenly or hellish beings

Jain scriptures also describe very minute life forms, including beings that live in water, earth, air, plants, and decaying substances. Because of this understanding, Jain conduct emphasizes great care in daily life, such as:

• Filtering water
• Avoiding unnecessary harm to earth, water, fire, air, and plants
• Practicing vegetarianism and, for many Jains, avoiding root vegetables
• Maintaining cleanliness and restraint

This knowledge was not based on modern microscopes. In Jain tradition, it is understood as spiritual knowledge revealed by the enlightened Tirthankars, who had perfect perception and perfect knowledge.

Spiritual Understanding

The main purpose of this teaching is not scientific curiosity, but Ahimsa — non-violence.

Jain Dharma teaches that countless living beings exist throughout the universe, including forms too subtle for ordinary perception. Therefore, a spiritual person should live with awareness, restraint, compassion, and humility.

Takeaway

Jains knew about subtle life forms through the omniscient knowledge of the Tirthankars and the Jain scriptural tradition. This understanding became the foundation for Jainism’s very careful practice of Ahimsa.