In the yoga system of psychology, there is the term Antah-karana, meaning “the inner instrument, ” which is the eleventh sense, 
in addition to the five active and the five cognitive senses. This Antah-karana, or the psyche, is divided into four faculties according to
function:
Manas: the active mind that receives sensations from the senses and sends forth reactions to them
Buddhi: the twofold faculty of discrimination, with its
- outward face, the intellect, and
- inward face, the intuitive wisdom
Ahamkara: ego, the faculty by which the· personality establishes its identity, such as “I am this body”
Chitta: the entire mind field, including the universal and individual unconscious, Manas. Buddhi and Ahamkara



