Samkhya's dualism is unusual among the world's dualisms in giving one of its two terms, purusha, no active powers at all: it does not think, choose, or act, but only witnesses, while every apparent activity of a person, thinking, choosing, feeling, perceiving, is assigned entirely to prakriti and its evolutes, principally buddhi (intellect), ahamkara (ego-sense), and manas (mind), all of which are unconscious material processes that merely appear to be a conscious self because purusha's light of pure awareness is reflected in them. Bondage, on this account, is not a moral failing but a case of mistaken identity: purusha, which is by nature free and untouched, comes to falsely identify with the workings of prakriti, taking prakriti's pleasures and sufferings as its own. Liberation, kaivalya, is achieved when this identification is seen through and purusha stands recognized in its own isolated, witnessing nature, a goal the Yoga Sutras of Patanjali describe through disciplined practice aimed at stilling prakriti's fluctuations so that purusha's true nature becomes evident.
Unlike Cartesian dualism, Samkhya's prakriti is not a passive backdrop but is itself dynamic, containing the three gunas, sattva, rajas, and tamas, whose shifting balance accounts for all the change and variety in the material and mental world, so the system needs no third substance to explain how a static matter becomes an active, changing cosmos.