"When one thinks, then he understands; without having thought, one does not know; it is only after having thought that one understands."
(Chhandogya Upanishad, VII-xxi-1)
"I was absent-minded; I did not hear. I was absent-minded; I did not see. It is thus evident that a person sees with the mind, hears with the mind. Desire, determination, uncertainty, belief, disbelief, steadiness, unsteadiness, shame, intellect, fear-all these are in the mind alone. Therefore, when touched from behind, a person knows by the mind. (Brihadaranyaka Upanishad, I-v-3)
There are two compartments in the mind, viz., the thinking portion and the perceiving portion. It is easy to stop the thinking portion, but it is extremely difficult to stop the functioning of the perceiving portion.
It is only the individual mind that sees objects outside. If you see the same objects through a telescope, they appear different. If you can see with the mind directly, you will have a different vision altogether. Hiranyagarbha or Karya Brahman has quite a different vision. He sees everything as a vibration or movement within himself as his own Sankalpa, just as you can imagine within your own mind that a big war is going on and many people are dying on either side. You withdraw your imagination at your will.
Theories Of Perception
There is the elastic theory of the mind. This school of thought says that the mind becomes elastic when several objects come in contact with the various senses and thus puts itself simultaneously into touch with various sense-organs or Indriyas of knowledge (Jnana-Indriyas). When the mind comes in contact with one object and one Indriya, it contracts to a point. This theory is exploded and refuted by the Vedantins as unsound.
There is another school of thought that says that there are different compartments or parts in the mind. One part of the mind connects itself with one sense (Indriya), another part with a second sense and so on. This theory is similarly blown up and discarded by the Vedantins as untenable and unsound.
According to the school of thought known by the name of Drishti-Srishti-Vada, the perceiver and the perceived are one. Just as the spider weaves out the web from its own body, even so the mind throws out this physical universe from its own body during waking state and withdraws the world into its womb during sleep. An object is a mental Vritti externalised or objectified.
The Drishya (what you see outside) is due to mental Avidya. There is only light outside. There is only vibration outside. It is the mind that gives colour and shape. It is all mental deception. This is one view. This is one theory of perception.
The interaction between the mind inside and the Tanmatric vibrations outside is the object or the world that you see outside. This is one theory of perception. Mind is formed out of the Sattvic portion of the five Tanmatras. There is light outside. The sun also emits light. The eye is made up of fire or Agni-Tattva. That portion of the mind which perceives is also made up of Agni-Tattva. So fire sees fire. Only that portion of the mind which is made up of Sabda-Tanmatra can hear. Sound comes from Akasa outside. So Akasa of the mind hears Akasa from outside. But, Atman can see, hear, taste and feel everything. Atman only can be seen by Atman. Therefore, whatever you see outside is Atman only. "Sarvam Khalvidam Brahma-Everything is verily Brahman."
The View Of Western Medical Science
According to western medical science, light-vibrations from outside strike the retina and an inverted image is formed there. These vibrations are carried through optic tract and optic thalamus to the centre of vision in the occipital lobe of the brain in the back part of the head. There, a positive image is formed. Then only, you see the object in front of you.
Perception According To Sankhya Philosophy
According to Sankhya philosophy, the real back-ground of perception is the Purusha of whom the western doctors and psychologists have no idea. Fleshy eyes are only external instruments (Karanas) for perception. Eye is not an organ of vision. The organ of vision is a centre situated in the brain; so is the case with all senses. Mind is connected with the Indriyas, the Indriyas with the corresponding centres in brain and the centres, with the physical organs, to the external object. The mind presents the sensation to Buddhi; Buddhi takes it to the Purusha (which is pure Spirit, which is Immaterial). Now, real perception takes place. Purusha gives order to Buddhi. Then, Buddhi, after proper decision and judgment and after taking into consideration the pros and cons of the subject on hand, gives orders back to the mind, for execution through the motor centres (Karma-Indriyas or organs of action). Buddhi is the Prime Minister and Judge who hears the statements of the Advocate, viz., the mind. Mind plays two parts, viz., (i) that of an Advocate and (ii) that of a Commander-in-Chief. After receiving decisive orders from Buddhi, the mind acts the part of a Commander-in-Chief and executes the orders of Buddhi through the five soldiers, the five Karma-Indriyas. This is the theory of perception according to the Sankhya Philosophy. See how very clear matters are in Hindu Philosophy.
First of all, there is the instrument or Karana-for instance, the fleshy eye. It takes the sense-impressions to the centre or Indriya. The mind is then connected with the centre and the external instruments, namely, the physical eye, ear, etc. The mind carries the impressions still further and presents them to the Buddhi, the determinative faculty, which reacts. Then flashes out the idea of egoism or Ahankara, which self-arrogates and identifies with Abhimana. Then the mixture of action and reaction is presented to the Purusha, the real Soul who perceives an object in the mixture.
Knowledge comes through contact with objects (Indriyartha-Sannikarsha). To know a Prapancha Vishaya, Indriya, Antahkarana and Jiva are required. Indriya will see the Vishaya. Mind will make it appear. Buddhi, with the help of Abhasa Chaitanya, will understand it. Mind, senses and the Karanas (external instruments) such as the physical eye, ear, etc., should all be joined together. Then only perception of an object is possible. The object comes in contact with the senses. The senses are linked to the mind. The mind is connected to the Atman. The Atman illumines. This is with reference to the physical plane.
The Vedantic Theory
According to the Advaitic theory of perception, it is the Chaitanya within us that makes perception possible. The Chetana within us unites with the Chetana in the object and the result is perception. It does not follow from this that the mind and the senses are useless. The senses are necessary for the adaptation of perception to their approximate things. From the soul's essential nature being intelligence, it does not follow that the senses are useless, for they serve the purpose of determining the special object of each sense.
The Vedantic theory of perception is that the mind comes out through the eye and assumes the shape of the object outside. The Antahkarana-Vritti enters through the opening of the Indriya (eye), removes Vishaya Ajnana, assumes Vishayakara (the shape and form of the object it envelops), presents the objects to your view. The function of Vritti is to cause Avarana-Bhanga (removal of the veil or layer of Sthula Avidya that envelops all objects).
A ray of the mind actually goes out, assumes the shape and form of the object and envelops it. Then only perception takes place. The perception of a book is possible only when the mind has assumed the actual shape of the book. Mental image plus external something is the object. Whatever objects you see outside, have got their own images in the mind.
When you pass through a mango garden, a ray of the mind comes out through the eye and envelops a mango. It assumes the shape of the mango. The ray is termed Vritti. The enveloping process is called Vritti-Vyapti. The function of a Vritti is to remove the Avarana (veil) that envelops the object and the Upahita Chaitanya. The veil that envelops the mango is removed by the Vritti or the mental ray. There is Chaitanya associated with the Vritti (Vritti Sahita Chaitanya). This Chaitanya illuminates the object 'mango'. This is termed Phala-Vyapti. Just as a torchlight illumines an object in a flash, this Vritti-Chaitanya illumines the object. Then only does perception of the mango take place. Mind makes Sankalpa-Vikalpa: Is this a mango or not? Buddhi comes to help the mind and determines (this is a mango) through previous experience. Chitta makes Anusandhana (enquiry): "How can I get the mango? May I ask the gardener or the proprietor?" Ahankara asserts: "I must get the mango anyhow. I want it." Then the command is given by the mind to the Karma-Indriyas for execution.
When you see a mango tree, it is external to you. There is externality. The mango tree is a mental percept. It is a mental concept also. There is no mango tree apart from the mind. You know the existence of the tree through the mind only. There is a mental image in the mind. The image in the mind plus the external something is the mango tree. Even if you close your eyes, you can get at the image through memory. The green colour of the leaves is due to a certain rate of light vibrations (say, 10 millions of vibrations). These light vibrations strike at the retina and are taken to the vision centre at the back of the brain. The mango-leaves have the power to split the white rays and absorb the green colour only. So says science.
Your body also is as much external to you as that yonder mango tree. It is also a mental percept or mental concept. The mango tree is external to you with reference to your body only. The mango tree itself is a mere appearance that floats in the Absolute or the One Reality. As the mango tree is external to you from the standpoint of your body, and as the body itself is external to you, the idea of externality of the mango tree or this external universe is blown up now. The term internality also has a false existence only. There is internality only with reference to the externality. If the externality goes away, where is the internality? Both the terms internality and externality are mere illusions, creations of the mind. There is only the solid existence, the One Reality or Absolute behind the so-called internality and externality. That is the Real, Infinite 'I'. That is your own Self.
Mind Alone Creates Differences
The eyes present before the mind some forms or images. It is the mind that creates good and bad forms. It says, "This is good. This is ugly. This is beautiful." Here comes bondage and trouble. Good and bad, ugly and beautiful are pure mental creations. If mind can create, it can destroy also. Similarly, the ears bring some sound vibrations before the mind. It is the mind that says: "This is praise. This is censure." Eyes and ears are not to be blamed at all. They are innocent. Mind causes the mischief.
Mental Cognition Takes Place Serially
Mind can think of only limited things. Mind cannot think of greenness without thinking of a green object.
Mind is Niravayava (without parts, divisions, compartments). It can have only one idea at a time. This is the Siddhanta of Naiyayikas. Even those Vedantins who say that mind is Savayava (with compartments) on the analogy of Chora-Nari (the prostitute whose mind is on the paramour even while she works in her house) admit that the mind can have Visesha Vritti of the lover only and Samanya Vritti of the work on hand at the time.
The human mind has the power of attending to only one object at a time, although it is able to pass from one object to another with a marvellous degree of speed, so rapidly in fact, that some have held that it could grasp several things at a time. Mind is a gate-keeper or guard who can allow only one person, one kind of sense-vibration at a time into the mental factory. You cannot hear and see at the same time. The mind can have only one idea at a time. But it moves with such tremendous lightning speed that an ordinary man thinks that he can have several ideas at a time.
Perception through the finite mind or cognition or experience takes place serially and not simultaneousely. Simultaneous knowledge can only be had in Nirvikalpa Samadhi where past and future merge in the present. Only a Yogin will have simultaneous knowledge. A man of the world with a finite mind can have only a knowledge in succession. Two thoughts, however closely related to each other, cannot exist at the same time. The nature of the internal organism (Antahkarana or Manas) prevents our having more than one aspect of an object at each instant presented to consciousness. Though several objects may come in contact simultaneously with the different sense-organs, yet the mind acts like a gatekeeper who can admit only one person at a time through the gate. The mind can send only one kind of sensation at a time into the mental factory inside for the manufacture of a decent percept and a nice concept.
When the mind gives attention and is attached to the sense of sight, it can only see. It cannot hear. It cannot hear and see at the same time. It is everybody's daily experience. When your mind is wholly absorbed in deep study of some interesting book, you cannot hear even if a man shouts, because the mind was not there (with the sense of hearing). "My mind was elsewhere, I did not see; my mind was elsewhere, I did not hear, for man sees with his mind and hears with his mind." Brihadaranyaka Upanishad, I-v-3). When you seriously think of a problem, you can neither see nor hear nor feel. All the Indriyas are detached from the mind. There is only the process of Anusandhana (enquiry or investigation) by the Chitta (the mental substance).
The best philosophers and seers, Rishis and sages, the best authorities, Eastern and Western, hold to the "Single Idea" theory as being correct. They are unanimously agreed that the mind cannot actually attend to more than one thing at a time, but when it appears to be doing so, it is only moving with prodigious rapidity backward and forward, from one end to the other. Illiterate people say that they can see and hear at the same time. The mind moves with a tremendous velocity backward and forward and people imagine that mind can do two things at a time. It is a sad mistake. A spark of light presents the appearance of a continuous circle of light if it is made to rotate rapidly. Even so, though the mind can attend to only one thing at a time-either hearing or seeing or smelling- though it can admit only one kind of sensation at a time, yet we are led to believe that it does several actions simultaneously, because it moves from one object to another with tremendous velocity, so rapidly that its successive attention and perception appear as a simultaneous activity.
Compensatory Advantage In Sense Perception
In some persons, the sense of hearing is more developed than the sense of sight. Judges have acute hearing. Commanders-in-chief have acute sight. The profession itself forces them to develop the particular sense. Blind people have acute sense of hearing. If one Indriya is defective, nature compensates by developing more another Indriya. One of my friends knows of a blind man who can feel the nature of the colour by mere touch.
Speech is even the sight of the Purusha. Speech means here sound, the object of the sense of hearing. When this sense is enlightened, reflection is produced in the mind. By the mind effort to obtain external thing is made; for by the mind one sees, one hears. When one, at a time at night in the dark, cannot distinguish where sound arises (be it the neighing of horses or the braying of donkeys or the barking of dogs), he resorts there whence speech proceeds.
It is the mind that really sees, tastes, smells, hears and feels. When you begin to think of the picture of Lord Krishna with closed eyes, it is through the mind's eye that you see the picture.
An occultist can dispense with his physical, fleshy eyes and can see directly with his mind. A Bhakta (devotee), being one with Isvara (Lord), sees directly with the eye of Isvara (with the eye of Karana-Sarira, seed-body). A Jnanin sees with the eye of Knowledge of Atman (Divya Drishti or Jnana-Chakshus).
How Brahman Perceives
In the mind, will and sight are separate. In pure Chit, will and seeing are one; will and sight are combined and no longer, as in the case of mind, separated from each other.
Brahman does not need Antahkarana to sense, think and reason. Brahman does not need eyes to see. He is self-luminous. He gives light to everything. He imparts light to Antahkarana. He gives light and power to the Indriyas. He is Chit-Svarupa. He is Chidghana. He is a mass of knowledge. He knows everything through Self-knowledge. He sees within Himself through Self-knowledge the whole universe as His own Sankalpa, as Vivarta.
How To Perceive Brahman
Brahman is not an object or Vishaya. It is to be felt by Sakshatkara (direct spiritual cognition). Knowledge of Brahman (Existence or Truth Absolute) comes through feeling and meditation (spiritual Anubhava, direct perception or Atma-sakshatkara) wherein the seer, sight and seen merge into the one existence like the bubble in the ocean.