Doctor: How to find the...? How to get to the ātman, the inner body?
Prabhupāda: Yes, that is the first instruction in the Bhagavad-gītā, that first of all, try to understand what is the person. So because we have no eyes to see, indirectly dehino 'smin yathā dehe kaumāram... (BG 2.13). Na hanyate hanyamāne śarīre (BG 2.20). Antavanta ime dehā nityasyoktāḥ śarīriṇaḥ (BG 2.18). So many things. Nainaṁ dahati pāvakaḥ. So many indirect way because we cannot directly perceive.
Doctor: Nainaṁ chindanti śastrāṇi nainaṁ dahati pāvakaḥ (BG 2.23).
Prabhupāda: What is called? Definition by negation. Nainaṁ chindanti—negation. So that you can have some idea.
Doctor: Of what it is.
Prabhupāda: It is not material. Because matter, chindanti, any matter it can be destroyed. It can be cut into pieces, it can be melted in fire, it can be moistened. So when we cannot understand things, it is given in the definition of negation.