Sāṃkhya Kārikā verse 31

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

sva - own; one's selfhetu - cause, cause of; motive; reason forvṛtti - fluctuation; modification; turning; set in motion, course of action, behaviour, movement; activity, function; professionpuruṣa - animating principle, self, consciousness, spirit; a person, man, a human being; peopleartha - purpose, aim; meaning; thing, objecteva - thusna - no; not; nor, neitherkaraṇa - making, effecting