Sāṅkhya & Yoga — The Map and the Method
Two of the six darśanas come as a pair: Sāṅkhya gives the map of what exists; Yoga gives the method of seeing it. Almost every other school borrows one or both.
The twenty-five tattvas
Prakṛti, the one root nature, unfolds into twenty-four principles through the three guṇas — sattva (clarity), rajas (movement), tamas (inertia). Puruṣa is not one of them. It is the witness who is not the witnessed.
Yoga — the method
Patañjali’s eight limbs do not add a metaphysics; they operationalize Sāṅkhya’s insight. Restrain the mind’s turnings (citta-vṛtti-nirodha), and the seer rests in its own form (kaivalya). Yama and niyama for conduct; āsana and prāṇāyāma for the body; pratyāhāra for the senses; dhāraṇā, dhyāna, samādhi for attention.