Antahkarana, the knowing self, it consists of mana (mind), buddhi (intellect) and Chitta (experiencing/recording self). According to Samkhya, these constitute the inner self (antahkaranam trividham – samkhyakarika 33). Some other schools add the fourth, consciousness. Their functions are – focusing, judgment, cognizing and reflecting. The Svetasvatara Upanishad adds conscience as the fifth.
The external sense organs are ten – five sense organs (eyes, nose, ears, tongue and skin) and five motor-organs (hand, feet, speech, organs of excretion and of generation). The five sense organs perceive an object and convey to the mind the details about the species, size, color, form and other such things. The sense organs are incapable of deciding. The mind enables focus on specific experience and passes on the information to the intellect. It is the intellect that decides whether the experience is in harmony with the self – it judges and decides. It has the function of cognition. The essence of the experience is then filtered into the citta, and all experience that filters into it in turn shapes and constitutes it.
Mind is one of the vibhuti-s (superior manifestations) of Krishna (the Bhagavad Gita X. 22). Mana, buddhi and ahamkara form three of the eightfold prakriti (nature) of Bhagavan Sri Krishna (Bhagavad Gita VII.4). This triad is part of the kshetra (field) (XIII.5). Buddhi all, it is the final form that our self takes. The chitta is to be controlled (6.12, 14). Verses 8 and 9 of the twelfth chapter of the Bhagavad Gita mention mana, buddhi and chitta and say – ‘place your mind in me, then fix intellect in me and if the pondering faculty is not composed then undergo the practice.’ The noun ‘chitta’ is used in the definition of Yoga as chitta-vritti-nirodha by Patanjali (Yoga Sutras 1.2) suggesting that chitta may be controlled through practice laid down in Yoga Sutras (I.12).
Thus, antahkarana consists of mana, buddhi, chitta, and ahamkara. Their order is the order of their functions in the process of cognition.