In the West, the concept of various planes of existence, and their varying principles of action and interaction, has been primarily the subject of what is known as “occultism”. Unfortunately, this term has been riddled with mis-information and misuse in the Western world, and thus, has been degraded in its significance. On the other hand, in the Mediterranean world and in the East, and in India particularly, knowledge of the esoteric principles upon which life is founded has been widely researched, experienced, organized, codified and validated. The information so developed has been found to be practical and verifiable. Different societies have of course chosen to focus on one or another aspect and thus, the field of esoteric knowledge seems to be extremely diverse. Sri Aurobindo observes, however, that the underlying facts agree: “We find that in the various systems the facts dealt with are always the same, but there are considerable differences of theoretic and practical arrangement, as is natural and inevitable in dealing with a subject so large and difficult.”
In order to examine the necessary aspects, Sri Aurobindo has chosen to use the well-defined and organized Vedic conceptualisation. He states his rationale: “But I shall follow here consistently the Vedic and Vedantic arrangement of which we find the great lines in the Upanishads, first because it seems to me at once the simplest and most philosophical and more especially because it was from the beginning envisaged from the point of view of the utility of these various planes to the supreme object of our liberation.”
The Upanishads, particularly the Taittiriya Upanishads, defines a series of ever subtler and more powerful planes of existence, starting with Matter, then Prana, the vital force, Mind, the Knowledge-Plane (Vijnana or as Sri Aurobindo refers to it, Supermind), and then the upper tier of Sat, Chit, Ananda, which are sometimes separated out in the review as separate planes of existence, and sometimes, because of their ultimate unity, as one level called Sachchidananda. These planes define the poises of consciousness available to the human individual, and successively moving the standpoint from one to the other brings forth the development of consciousness and its evolution to the higher and more powerful forms that lie in our future through the unfolding of the universal manifestation.
Sri Aurobindo, The Synthesis of Yoga, Part Two: The Yoga of Integral Knowledge, Chapter 19, The Planes of Our Existence, pp. 428-429