Sāṃkhya Kārikā verse 18

जननमरणकरणानां प्रतिनियमादयुगपत्प्रवृत्तेश्च । पुरुषबहुत्वं सिद्धं त्रिगुण्यविपर्ययाच्चैव ॥१८ ॥

janana-maraṇa-karaṇānāṃ pratiniyamāt-ayugapat-pravṛtteḥ ca |
puruṣa-bahutvaṃ siddhaṃ tri-guṇya-viparyayāt-ca-eva ||

janana - generating, begetting, producing, causingmaraṇa - the act of dying, deathkaraṇa - a helper, companion; instrument, means of action; doing, making, effecting, causing; the act of making, doing, producing, effectingpratiniyama - A separate allotmen; A general rule; a strict rule as to applying an example to particular persons or things onlyayugapad - not at once, not simultaneously; not all together, graduallypravṛtti - activity, exertion, efficacy, function; finer cognition, special cognition, sensuous cognition; moving onwards, advance, progressca - andpuruṣa - contentless consciousness; animating principle; unchanging self; pure consciousness; spirit; a person, man, a human being; peoplebahutva - muchness, abundance, multitude; plurality, majoritysiddhi - accomplishment, performance, fulfilment, attainment, success; the hitting of a mark; coming into force, validity; any unusual skill or faculty or capability; the acquisition of supernatural powers by magical means or the faculty so acquiredtri - threeguṇa - an ingredient or constituent or attribute of nature; a property or characteristic of all created things; qualities; a quality, peculiarity, attribute or property; the peculiar properties of the lettersviparyaya - wrong perception, misapprehension, error, mistake; intrinsic misconception; reversed, inverted, perverse, contrary toeva - indeed, truly, really; thus; so, just so, exactly so

Commentaries and Reflections

Commentary by S Ramaswami:

The question of plurality of Puruṣa.

janana- Birth
maraṇa- Death
karaṇānām- Instruments of activity.

1) From the incidence of birth and death and the endowment of the instruments of cognition and action, of activity.
pratininyamāt- Separately controlled. Separate for separate people.
2) ayugapat-pravṛtteḥ- ca- Experiences do not take place at the same time.
3) traiguṇya-viparyayāt-ca-eva- The interplay of the Guṇa is different for different people.
puruṣa-bahutvam-siddham
Because of these three reasons the Multiplicity of Puruṣa is infinite.
—
The properties of Puruṣa or Spirit are discussed next.