“It is not possible for us to reach an exact understanding of the fundamental importance of this aspect (of the manifested Diversity) to the principle or law of the brotherhood of all humanity without taking into account the knowledge of the inner constitution of man or the evolutionary process of the human Soul through successive reincarnations. In this sense, the first fact of importance for an appropriate view of the human being as a whole which is revealed to us by the Perennial Philosophy is that of the existence of matter on many levels of density more subtle than those that are well known scientifically.
The important fact to our study is that man possesses bodies manifested on all these planes, even though, in accordance with his level of evolution, some may be quite underdeveloped. Thus, the human being is essentially a Ray or Spark of the Sun of the One Divine Consciousness, rooted in the highest or divine plane. From this point on, this Divine Consciousness in man covers itself with the body appropriate to its expression on all planes and sub-planes of density of matter, including the physical.
In accordance with the Esoteric Philosophy, if we observe all of the constitution of man, from its densest to its most subtle body, it would be as follows: (1) a physical dense body, of flesh and bone, which corresponds to the solid, liquid and gaseous levels of the physical plane; (2) a first invisible body or aura, called etheric double, which belongs to the four etheric sublevels of the physical plane; (3) an astral or emotional (body or aura), made up of matter from the seven sublevels of the astral plane; (4) a concrete mental body made up of matter from the four densest mental sublevels; (5) an abstract mental body made up of matter from the three sublevels of more subtle mental matter; (6) an intuitive or buddhic body with matter from all sublevels of this plane; (7) a body of spiritual or atmic volition made up of matter from the four inferior sublevels of the atmic plane; (8) a Monad or Divine Spark, the reflection from the Divine Trinity in man, which is expressed beginning with the three higher atmic sublevels, up to the heights of the divine plan.
According to St. Paul’s well-known classification, the human being is composed of a body, a soul, and a spirit. Analogously, according to the Esoteric Philosophy, man is inhabited by a transitory personality (from the Greek, persona = mask), an immortal Ego, and a Divine Spirit. This personality is made up of the lower quaternary (the composition formed by the dense physical body, the etheric double, and the astral and mental bodies), which perishes, or renews itself, at each new incarnation. The Higher Ego is made up of the Higher Triad (the composition formed by the Higher Mental or Causal, Buddhic, and Atmic bodies). This Ego is immortal and is a reflection or manifestation of the Monad or Divine Spirit of man, which is always one with the Divine.
The total constitution of man described above may be visualized more easily with the help of the figures below (pp. 9 and 23, in Dr. Taimni’s book, “Self-culture in the Light of Occultism”). In the context of this work we cannot go deeper into this fascinating knowledge of the inner constitution of man, which can be found in the books devoted to this subject, for instance, “Man and His Bodies” by Dr. Annie Besant.”
(Arnaldo Sisson Filho. Theosophy and Universal Brotherhood, — Chapter VII)