In Jainism, the concept of soul (jīva) and its relation to the body is very specific. According to Jain philosophy, every living being possesses a soul, and the soul pervades the entire body it inhabits. The soul is formless, but it spreads throughout the body it occupies, conforming to its shape and size.

If a living body (such as a plant or an animal) is cut into pieces, Jainism teaches the following:

• Each piece that is capable of independent life will have its own soul. For example, if a worm is cut into two and both parts survive and move independently, each part is considered to have its own jīva.
• If a non-living object (like a rock) is cut, Jainism considers rocks as non-living, unless they are classified under "ekendriya jīva" (one-sensed beings, such as earth-bodied beings). In the case of a living earth-bodied being (prithvikāya), when it is broken, each fragment which is still capable of sustaining life will have a separate soul pervading it.
• The original soul does not cover both pieces. When a living being is divided, the original soul departs from the body part that cannot sustain life. If both parts can sustain life, new souls may occupy the separated parts, or each may continue with its own soul.

Key Jain Principle: The soul pervades only the body it currently inhabits and does not extend into separated parts if they are no longer capable of sustaining life. Each living, independent body has its own soul.

References:

• Tattvartha Sutra (Dravyasamgraha, Sutra 17-18)
• Jainism: The World of Conquerors by Natubhai Shah
• Jain Philosophy and Practice I by JAINA Education Committee