Sāṃkhya Kārikā verse 31

svāṃ svāṃ pratipadyante paraspara-ākuta-hetukāṃ vṛttim |
puruṣārtha eva hetuḥ na kenacit kāryate karaṇam ||

sva - own; one's selfpuruṣa - animating principle, self, consciousness, spirit; a person, man, a human being; peopleartha - purpose, aim; meaning; thing, objecteva - thushetu - cause, cause of; motive; reason forkaraṇa - making, effecting