And what is this deepest? The physical body, being outside as a part of the physical world, should be considered an object like the other things of the world, and it is constituted of the five elements. This material body of five elements acts as a vehicle for certain powers that work from within. Our actions are movements of these powers. There is an energy within the body which is other than the elements. This energy is called prana or vital force. The prana has many functions, which are responsible for the workings of the body. The organs of action, viz., speech (vak), hands (pani), feet (pada), genitals (upastha) and anus (payu) are moved by the motive power of the prana. But the prana is a blind energy and it needs to be directed properly. We know we do not just do anything at any time, but act with some, method and intelligence. There is a directing principle behind the prana. We think before we act. The mind is, therefore, internal to the prana. But thought, again, is regulated by something else. We engage ourselves in systematic thinking and follow a logical course in every form of contemplation and action. This logical determinant of all functions in life is the intellect, which is the highest of human faculties, and it is inseparable from the principle of the ego in man. 

All these functions of the psychological apparatus are, however, confined to what is called the waking state. The human being seems to be passing from this state to others, such as dream and deep sleep. Though we have some sort of an awareness in dream, we are bereft of all consciousness in deep sleep. Yet, we know that we do exist in the state of sleep. This means that we can exist without doing anything, even without thinking. The condition of deep sleep is a paradox for psychology and is the crux of the yoga analysis. It is strange that in sleep we do not know even our own selves, and still we know that we do exist then. An experience, pure and simple, of the nature of consciousness alone, is the constituent of deep sleep, notwithstanding that we are not aware of it due to a peculiar difficulty in which we seem to get involved there. In deep sleep, we have consciousness not associated with objects, and hence we remain oblivious of everything external. There is, at the same time, unconsciousness of even one's own existence due to there being the potentiality for objective perception. The result is, however, that the deepest in the individual is consciousness, which is called by such names as the Atman, Purusha, etc. This is the real Self. 

Now, what is the deepest in the cosmos? We learnt that there are five elements. But this is not the whole picture of creation. There are realities within the physical universe as they are there within the individual body. If the prana, mind, intellect, ego and finally consciousness are internal to the bodily structure, there are also tremendous truths internal to the physical universe. Within the five gross elements there are five forces which manifest the elements. These forces are the universal causes of everything that is physical, and are called tanmatras, a term which signifies the essence of objects. There is such a force or power behind the elements of Ether, Air, Fire, Water and Earth. Sabda or sound is the force behind Ether. But this sound is, different from what we merely hear with our ears. It is the subtle principle behind the whole of Ether, on account of which the ears are capable of hearing at all. This is sound as tanmatra. Likewise, there are the tanmatras of Air, Fire, Water and Earth, called respectively sparsa or touch, rupa or form, rasa or taste and gandha or smell. These powers are subtle energies immanent in the elements constituting the physical universe. 

Modern science seems to corroborate the presence of these, essences behind bodies. The world was once said to be made up of molecules or chemical substances. Further investigation revealed that molecules are not the last word and that they are made up of atoms. Research, again, proved that even the atoms are formed of certain substances, which have the character of both waves of energy and particles of force. They flow like waves and sometimes jump like particles. A great physicist has therefore preferred to designate them as 'wavicles'. These have been named electrons, protons, neutrons, etc., according to their structure and function. Their essence is force. There is nothing but force in the universe. There is only a continuum of energy everywhere. The tanmatras of the yoga system, however, are subtler than the energy of the scientist, even as the prana is subtler than electricity. 

Just as behind the prana there is the mind, behind the tanmatras there is the Cosmic Mind. Beyond the Cosmic Mind are the Cosmic Ego and the Cosmic Intellect, the last mentioned having a special name, mahat. Beyond the mahat is what is called prakriti, in which the whole universe exists as a tree in a seed, or as effect in its cause. Transcending prakriti is the Absolute-Consciousness, called Brahman, Paramatman and the like. So, whether we dive deep here or there, within ourselves or within the cosmos, we find the same thing - Consciousness. And the stages of manifestation in the individual correspond to those in the universe. The purpose of yoga is to effect a communion between the individual and cosmic structures and to realize the ultimate Reality. The yoga places before us the goal of a union wherein infinity and eternity seem to come together. The aim of yoga is to raise the status of the individual to the cosmic level and to abolish the false difference between the individual and the cosmic. The cosmos includes ourselves and things. The individual is a part of the cosmos. Then, why do we make a separate reference to the individual? This is a mistake, which yoga effectively corrects. To regard the cosmos as an outer object would be to defy the very meaning of the cosmos. To imagine ourselves to be subjects counterposed before an object called the cosmos would be to stultify the comprehensiveness of the cosmos and to interfere with its harmony and working. The yoga rectifies this mistake and hereby the mortal becomes the Immortal. As the individual is a part of the cosmos, this achievement should not be difficult. The individual is not separate from the cosmic, but there seems to be some confusion in the mind of the individual which has caused an artificial isolation of itself from the rest of the universe. This confusion is called ajnana or avidya, which really means an absence or negation of true knowledge. Here we enter the realms of depth psychology.