sattwa the principle of assimilation, equilibrium and harmony. The metaphysical bearing of this classification does not concern us; but in its psychological and spiritual bearing it is of immense practical importance
Aurobindo defines sattwa as the guna of assimilation and equilibrium and argues that its psychological and spiritual import — not its metaphysical classification — is what matters for yogic practice.
, The Synthesis of Yoga, 1948thesis