Adhyāya 39 — त्रिगुणविवेकः (Discrimination of the Three Guṇas) and Avyakta-Doctrine
व्यतिरिक्तं तमो यत्र तिर्यगू भावगतं भवेत् | अल्पं तत्र रजो ज्ञेयं सत्त्वमल्पतरं तथा,तिर्यग् योनियोंमें जहाँ तमोगुणकी अधिकता होती है, वहाँ थोड़ा रजोगुण और बहुत थोड़ा सत्त्गगुण समझना चाहिये
vyatiriktaṃ tamo yatra tiryagū bhāvagataṃ bhavet | alpaṃ tatra rajo jñeyaṃ sattvam alpataram tathā ||
Vāyu said: 'Where, among the animal modes of existence, darkness (tamas) predominates and stands apart as the chief quality, there one should understand passion (rajas) to be only slight, and goodness (sattva) to be slighter still.' The verse frames an ethical psychology: lower births are characterized by obscuration and inertia, with only limited impulse and very little clarity for discernment.
वायुदेव उवाच
The verse teaches a guṇa-based understanding of embodied states: animal existence is typically dominated by tamas (delusion/inertia), with only a small presence of rajas (impulse/activity) and an even smaller presence of sattva (clarity/discernment). Ethically, it implies that clearer moral judgment and self-governance are harder where sattva is minimal.
Vāyudeva is explaining the distribution of the three guṇas across different modes of birth. In this segment he characterizes tiryag-yoni (animal forms) as chiefly tamasic, setting up a broader teaching on how qualities shape behavior, capacity, and moral agency.