Samkhya Karika 21

पुरुषस्य दर्शनार्थं कैवल्यार्थं तथा प्रधानस्य ।
पङ्ग्वन्धवदुभयोरपि संयोगास्तत्कृतः सर्गः ॥ २१ ॥

puruṣasya darśanārthaṁ kaivalyārthaṁ tathā pradhānasya ।
paṅgvandhavadubhayorapi saṁyogāstatkṛtaḥ sargaḥ ॥ 21 ॥

Puruṣasya=of the Purusha; darśanārthaṁ=for the sake of exhibition; kaivalyārthaṁ=for the purpose of liberation; tathā=and; pradhānasya=of Prakriti;
paṅgu=lame; andhavat=like the blind; ubhayoh=of both; api=too; saṁyogaḥ=union;  tatkṛtaḥ=results in; sargaḥ=creation

For the exhibition of the Prakriti to the Purusha and for the liberation of the Purusha, union between Purusha and Prakriti happens just as the union between the lame and the blind. Creation proceeds from this union.

This karika explains the purpose of the union between Purusha and Prakriti.

All the experiences in life are happening at the level of Prakriti through the combined action of all the 23 elements. Buddhi (intellect) presents all such experiences to Purusha. Due to the constant interplay of the three gunas, all the three types of dukhas (suffering), as described in karikas 1 and 2, are presented to the Purusha. Of course, the goal being elimination of the three types of suffering, Prakriti has to develop discriminative knowledge which would lead to the liberation (kaivalya) of Purusha.

As we recall, Patanjali, in the Yoga Sutras has mentioned the goal of Prakriti being bhoga (experiences) and apavarga (liberation) (sutra 2.18). The same concept is mentioned in the present karika.

The union of a lame person and a blind person is given as an illustration as to how the two work together to reach their destination. The lame person cannot walk but can see, while the blind can walk but can’t see. So, they team together – the lame person climbs on blind person’s back and guides him to go to their destination. Once they reach the destination, they can go their separate ways. In the same manner, Prakriti does not act but has consciousness whereas it’s just the opposite for the Prakriti. It needs to borrow the consciousness from Purusha to carry on with its activities.

The karika further states that the creation is the result of this ‘union’ between Purusha and Prakriti