Tamas is the principle and power of inertia; rajas is the principle of kinesis, passion, endeavour, struggle, initiation; sattwa the principle of assimilation, equilibrium and harmony.
Aurobindo identifies inertia as the precise psychological and metaphysical content of tamas, the first of three gunas that govern all natural experience, making it a foundational cosmological category.
, The Synthesis of Yoga, 1948thesis