Few people reflect on the instruments or methods of knowing that we employ. We take the senses for granted, as well as the operation of the mind. We experience the world around us and consider it to be real and experienced by everyone else the same way. Over the last few hundred years, however, Western philosophers and psychologists have begun to explore the questions that underlie these assumptions. Many now accept that our experience is subjective and that we do not really know the objective reality, we only know what our senses perceive and our mind interprets.
It is interesting to note that the Rishis in India took up these issues several thousand years ago! The Kena Upanishad is focused on trying to understand the operations and role of the senses and the action of the mind, how and under what force of impulsion we actually experience and interpret the material and vital world and life around us. They went even further however by turning the attention to other realms of consciousness that are the source of our awareness. They quickly recognized that just as material or vital existence cannot fully understand or comprehend the mental world of thought, so also the mind could not fully capture or embrace any higher status of consciousness. In order to understand, therefore, any higher realms, new stages of consciousness would need to be developed.
Sri Aurobindo notes; “The Kena Upanishad … concerns itself only with the relation of mind-consciousness to Brahman-consciousness and does not stray outside the strict boundaries of its subject. The material world and the physical life are taken for granted, they are hardly mentioned. But the material world and the physical life exist for us only by virtue of our internal self and our internal life. According as our mental instruments represent to us the external world, according as our vital force in obedience to the mind deals with its impacts and objects, so will be our outward life and existence. The world is for us, not fundamentally but practically at any rate, what our mind and senses declare it to be; life is what our mentality or at least our half-mentalised vital being determines that it shall become. The question is asked by the Upanishad, what then are these mental instruments? what is this mental life which uses the external? Are they the last witnesses, the supreme and final power? Are mind and life and body all or is this human existence only a veil of something greater, mightier, more remote and profound than itself?”
“The Upanishad replies that there is such a greater existence behind, which is to the mind and its instruments, to the life-force and its workings what they are to the material world. Matter does not know Mind, Mind knows Matter; it is only when the creature embodied in Matter develops mind, becomes the mental being that he can know his mental self and know by that self Matter also in its reality to Mind. So also Mind does not know that which is behind it, That knows Mind; and it is only when the being involved in Mind can deliver out of its appearances his true Self that he can become That, know it as himself and by it know also Mind in its reality to that which is more real than Mind. How to rise beyond the mind and its instruments, enter into himself, attain to the Brahman becomes then the supreme aim for the mental being, the all-important problem of his existence.”
Sri Aurobindo, The Upanishads, Kena Upanishad and analysis, pp. 111-116