The cause of avoidable suffering is the union of the seer with the seen.

Saṃyoga is the union or identification between draṣṭṛ (the seer, puruṣa) and dṛśya (the seen, prakṛti). This fundamental confusion is the root of all suffering.

Puruṣa is pure consciousness, without qualities, immutable. Prakṛti is the field of manifestation, changing, composed of the guṇas.

When consciousness identifies with the contents of experience—the body, emotions, thoughts—suffering arises.

Liberation consists in dissolving this erroneous identification, in recognizing that the seer was never really the seen.

This sutra points directly to the cause that must be eliminated.