Tamas (Sanskrit: तमस् tamas, lit. 'darkness') is one of the three guṇas (tendencies, qualities, attributes), a philosophical and psychological concept developed by the Samkhya school of Hindu philosophy.[1] The other two qualities are rajas (passion and activity) and sattva (purity, goodness). Tamas is the quality of inertia, inactivity, dullness, or lethargy.