reference:
Sri Aurobindo and the Mother, Our Many Selves: Practical Yogic Psychology, Introduction, Sri Aurobindo on Our Many Selves, Planes and Parts of the Being, pp. xxi-xxiii
This episode is also available as a blog post: https://sriaurobindostudies.wordpress.com/2023/06/09/the-outer-mental-vital-and-physical-consciousness-of-the-external-being/