Rigveda has a wealth of knowledge about human psychology. But like everything else in the Veda, this knowledge is intimately related to the knowledge of cosmology, devās etc. The seers of RV viewed a human being as a symbol of the Supreme Divine. This is the natural meaning of the famous Puruşha hymn (10.90) in RV. It is a grotesque interpretation to claim that this hymn portrays the Supreme Person as having a physical form of the human being, the so called anthropomorphic conception of God. The word puruşha is used in the Veda both for the Supreme Divine as well as for the human. This word literally means a dweller in the city puri or one who pervades everything. Every human being has a complex inner structure of which the physical body is only one aspect, the other aspects being those beyond the pale of the senses. In modern language used by the tāntriks, every human being is endowed with several bodies which are termed as subtle to distinguish them from the gross physical body. The subtle body is indicated by the word sadana, sadma, yoni, etc., in many verses. Each body is associated with a distinct psychological principle. There is an intimate connection between the subtle bodies associated with a human being and the various worlds of the cosmos of Rigveda. Thus a key idea of the RV is that every human being’s structure mirrors that of the cosmos. This connection between the individual human and the cosmos also affirms the connection between the corresponding bodies of all the different human beings. For instance, the individual mind of each human being is derived from the cosmic mind and thus all the individual human minds are in touch with one another. This feature explains many of the well known facts such as thought-reading, i.e., the reading of one person’s thought by another, the possibility of simultaneous discoveries in the scientific arena and so on.
As mentioned earlier, the structure of human being replicates that of the macrocosm. Each person has several different sheaths or bodies, one corresponding to each principle of consciousness mentioned above. The same names are used for the sheaths also. However, in most humans only the outer three sheaths associated with the worlds of earth, antarikşha and dyau have developed; the fourth sheath termed as mahas in Upanishads is not developed in most humans.
The outermost sheath is the sheath of matter, derived from the world of matter. Next s/he has the sheath of life-energy which deals with ambitions, emotions, higher levels, feelings, both noble and petty, goals, urge to dominate, drives, desires to possess, anger, urge for progression, the power of love, faith, sincerity, humility, aspirations, equality, peace, generosity, goodness, emotion, passion and love. The mental sheath deals with our thoughts, understanding, control of senses, intelligence, reason, intuition, ability to make decisions and implement them, control of the organs of actions like speech, hands, legs etc., and the powers of meditation, contemplation and concentration. Typically in an advanced person the sheath of prāņa or the vital should be under the control of the mind. Often it is the reverse, the vital overpowers the mental and orders the power of reasoning to come up with reasons for doing the action, which may have no support of our secret inner being.
So, when a human is reasoning, he is communing with the mental world. When s/he is involved with emotions like love and the powers of the higher vital s/he is communing with the vital world, antariksha. Those who are deemed intellectual, commune mainly with the vital and mental worlds.
In an ordinary human being, martya or marta, these different bodies are still in a nascent state. All the associated energies are blocked as it were and the symbolic doors of the respective rooms are closed or almost closed. When the doors are at least slightly open, a person, while thinking, will be in touch with the world of dyau; while dealing with life energies is in touch with the mid-world etc.
The key difference between the human being and the Divine is that the cosmic worlds associated with the Divine are perfect. There is a sheath in human being corresponding to every world. But these are in a process of evolution in different stages of development. This is the reason for the distinctness of each human being. Each human being is at a different stage of development. The rişhis of RV reached a sufficiently high stage of development in all the four sheaths. In most human beings even the third or mental sheath is not well developed, leave alone the fourth sheath. All the psychological problems faced by the humans are derived from the fact that these sheaths are not fully developed.
The Veda distinguishes between the ordinary mortal marta or martya and the wise person, vipra, rişhi or kavi, one who has the vision of entities beyond the range of senses. It tells how one can attain these states of consciousness and other states of mind.
Recall that the goal stated in the Rigveda is the attainment of immortality or perfection in all aspects. This aim is stated in various places such as (9.113). Immortality is not mere freedom from death and living in the aging body for ever. The decay of our physical and mental powers is the characteristic of mortality. The devās help the eager aspirants in attaining the many sided perfection. When the human beings express their aspiration by means of practices like meditation and chanting, the devās reveal themselves and manifest their powers in that human being. They are said to be literally born in the rişhi. Hence the devās are said to be ŗşhikŗt, makers of rişhis (1.31.16). Agni is the god hymned first because he represents the power of aspiration. Even when the outer human being is completely ignorant, Agni puts pressure and makes the human being become aware of the inner body. When the aspirant realises the necessity for understanding the world inside, he intensifies his practices of meditation and chanting. Then the Agni power becomes firmly established. Then Agni himself carries them further. He calls all other devās to come and manifest in the aspirant. In the symbolic language of the deva, Agni himself is called upon to perform the yajňa.
The progress achieved in the humans is indicated in several verses. For illustration, consider the action of ŗbhus, the divine artisans who prepare the subtle bodies of the human beings. One of their actions is indicated by the enigmatic phrase, “They make four bowls out of the One”, (1.20.6). Sri Aurobindo explains the symbolism. In an ordinary human being, our physical, vital and mental aspects are all mixed up. Each aspect wants to act independent of the other. The physical body has its needs. The vital body forces its desires and ambitions on both the physical body and mental body to the harm of the latter. The ŗbhus isolate the warring factions and restore order. Thus they form the physical body, vital body, mental body and the body of light from the amorphous single one, the single bowl.