Yoga Sutra - Sādhana Pada 2.48
ततो द्वङ्द्वानभिघातः ॥४८॥
tataḥ dvandva-anabhighātaḥ ||48||
Thus, there is no assault by the pairs of opposites.
The cause of conjunction is ignorance.
Vācaspati Miśra and Vijñānabhikṣu elaborate somewhat on the fourth possible cause of ignorance outlined in the previous sūtra. Creation in Hindu cosmology is cyclical. At the end of each cosmic cycle, all manifest reality, the world and the evolutes of prakṛti, dissolve back into their original source matrix along with the souls in saṁsāra—the puruṣas who have not attained liberation—and remain there latent and inactive until the next cosmic cycle begins anew. This primordial soup, called pradhāna, thus contains all the saṁskāras from all the cittas of all the individual puruṣas that had not had a chance to fructify during the last cycle.46 At the beginning of the new cycle, these saṁskāras reactivate and cause pradhāna to produce an individual citta for each puruṣa appropriate to the specific saṁskāras possessed by that same puruṣa at the end of the last cycle. The puruṣa is thus like a fish trapped in a net of its previous saṁskāras and karma, says Rāmānanda Sarasvatī. As a result of the puruṣa being reconnected with a citta, its previous saṁskāras, most notably the saṁskāra of ignorance (i.e., the misidentification between the puruṣa and prakṛti), reexert their influence. In other words, the puruṣa picks up where it left off. The point is, from this perspective, that it is the saṁskāras that cause ignorance. This cycle of creation and dissolution is eternal for the Yoga school until liberation occurs (saṁsāra has no beginning, but it has an ending). Since the eternality of this cycle is axiomatic, the Yoga school avoids having to account for any primordial saṁskāra of ignorance that may have activated the whole cycle in the first place.
When intelligence contains the saṁskāras of ignorance, says Vyāsa, it remains active in the realm of prakṛti and thus does not produce discrimination about the true nature of puruṣa. Saṁskāras impel the intelligence to perform the first of its two functions, as expressed in II.18, namely, to provide experience of prakṛti, and it is this that is the cause of bondage. Intelligence ceases its activity only when it has attained its alternative and ultimate function, which is to provide discrimination about the distinction between puruṣa and prakṛti. As was discussed in some detail in I.50, the saṁskāra of discrimination overpowers all other saṁskāras. When this happens, ignorance, avidyā, the cause, hetu, of bondage, is removed, and ignorance, we recall, is the support of the other kleśas, obstacles (II.3–4), so they, too, dissolve.
In other words, complete liberation occurs only when intelligence first provides discrimination and then ceases to act altogether. Although discrimination, a function of buddhi, is initially indispensable in attaining the goal of yoga, as long as it remains active, puruṣa is still connected with buddhi, and thus complete liberation is not realized. But discrimination eventually completely destroys ignorance and thus its own base, like fire destroys its own fuel, says Hariharānanda. This results in asamprajñāta-samādhi, the final goal of yoga.
One might argue, says Vyāsa, that this claim that full liberation occurs only after discrimination has dissolved itself is rather like an impotent man who, when asked by his wife why she does not have children as her sister has children, replies that he will beget children in her after he is dead. If intelligence cannot provide liberation while it is alive and active, why should one believe that it will do so after it becomes lifeless and inactive? Vyāsa affirms, again, that full and final liberation occurs precisely when the intelligence ceases to act. Intelligence ceases to act when ignorance is removed. And ignorance is removed by knowledge. In other words, bondage is caused by ignorance, ignorance is removed by knowledge, the discriminatory aspect of intelligence, and then intelligence, having performed its grand finale, ceases to operate, and the full freedom of puruṣa occurs. Thus, intelligence and knowledge are not the direct cause of liberation, but by removing ignorance, they are the indirect cause.