The Sankhya system is a dualistic system; it admits purusha and prakriti as two realities. Purusha is conscious by nature. It is just a seer. Prakriti, on the other hand, is unconscious, ever active. Prakriti is made of three gunas, which are sattva, rajas, and tamas. Each of the three gunas represents a different aspect of reality. Sattva signifies purity, rajas signifies activity, and tamas signifies resistance.
The first thing to emerge from Prakriti is the mahat-tattva or buddhi which, in turn, gives rise to ahamkara or the ego-sense. From the sattva phase comes out the five senses of knowledge, the five senses of action, and the mind. From the tamas phase of it emerge the five subtle elements; and, the five gross elements come into existence from rajas. Purusha is conscious and absolute. The sattva phase of the buddhi consists of the characteristics, which are merit (dharma), detachment from worldly objects (viraga), and lordly powers (aishwarya). The tamas phase of it is characterized by the qualities, which are demerit (adharma), non-discrimination between the purusha and the buddhi (ajnana), desire for worldly objects (avairagya), and absence of lordly powers (anaisvarya).