Antahkarana is a collective term for the 4 tattvas-prakṛti,buddhi,ahamkāra and manas.Consciousness within the limited purusha forms the citta made of Intellect (buddhi), Ego (ahamkāra), and Mind (manas), known collectively as the antahkarana, or "inner organ". Buddhi is the first evolute of prakṛti. It represents the capacity of discernment. It evolves into ahamkāra after buddhi differentiates a notion of a limited individual self. That external sense of self is then experienced through the sensory mind (manas). Ten indriyas (five sense organs and five action organs), five tanmātras (subtle elements), five mahābhūtas (gross elements), and the sensory mind evolve from ahamkāra as it modifies into sattvic (sensory), rajasic (active) and tamasic (material) modes. These 24 lowest tattvas that evolve from individual consciousness are known as the impure tattvas (aśuddha).
