YSA 04.06.22 Scriptural Topic with Hersh Khetarpal
Definition of the three bodies -
Karana sarira or the causal body is merely the cause[1] or seed of the subtle body and the gross body. It has no other function than being the seed of the subtle and the gross body. It is nirvikalpa rupam, "undifferentiated form". It originates with avidya, "ignorance" or "nescience" of the real identity of the atman, instead giving birth to the notion of jiva.
Sukshma sarira or the subtle body is the body of the mind and the vital energies, which keep the physical body alive. Together with the causal body it is the transmigrating soul or jiva, separating from the gross body upon death.
Sthula sarira or the gross body is the material physical mortal body that eats, breathes and moves (acts). It is composed of many diverse components, produced by one’s karmas (actions) in past life out of the elements which have undergone panchikarana i.e. combining of the five primordial subtle elements.