The Intelligence of Pure Consciousness — Chitta as the Mirror of Purusha
Patanjali's most subtle teaching: the chitta (mind-stuff) is not consciousness itself but its reflection — and the confusion of this reflection for the original is the mechanism of all bondage.
Sutras 4.18-4.24 develop Patanjali's most sophisticated analysis of the relationship between Purusha (pure consciousness) and chitta (mind). The mind is illuminated by consciousness the way a mirror reflects light — the mirror appears to shine, but the light is not its own. Sutra 4.19 states: 'na tat svabhasam drishyatvat' — the mind is not self-luminous, because it is an object of perception. Pure consciousness illuminates the mind; the mind then appears to be conscious. This subtle distinction — between the genuinely self-luminous consciousness (Purusha) and the derivatively luminous mind (chitta) — is the most precise instrument Patanjali provides for Viveka practice: every time the mind seems to be experiencing, a more careful investigation reveals that consciousness is witnessing the mind experiencing.
The mind is not self-luminous, since it is an object of perception.
Philosopher David Chalmers' hard problem of consciousness — the question of why and how physical processes give rise to subjective experience — is precisely the problem that Patanjali's Purusha-chitta distinction addresses: by positing a consciousness that is categorically irreducible to any physical process, Patanjali offers a resolution that Western philosophy has not yet achieved.
Yoga Sutras of Patanjali