Sri Aurobindo
Letters of Sri Aurobindo
Volume I - Part 1
If your definition is correct, consciousness cannot be a self-existent reality; it is a result, a phenomenon dependent on the reactions of something – you say a personality, but what is a personality apart from consciousness? – to the universal forces of Nature. We can take a purely external view and say that consciousness is the result of a mass of reactions to the impact of outward physical things on the brain and nerves of a physical being. In this case consciousness is a sort of effective hallucination – there is no real and permanent consciousness but only a subjective impression created by a constant activity of reactions. As a number of dancing fires may create a glow in the sky, so consciousness is created by these reactions and is suspended or disappears when they halt or cease. In your definition you add a real (?) subjective personality and supplement the reactions of physical outward things by reactions of inner things or things from above or below. But still the consciousness is only a seeing or interpretation of reactions,– it is a result of them, a phenomenon. If there are no more reactions, consciousness ceases to exist – for what other basis has it or standing place than the impermanent reaction to forces? Unless it is something intrinsic and inherent in the “subjective personality”; but then it is not a result of the reactions or a seeing and interpretation of them, but rather the reactions are the result of a pre-existent consciousness and the seeing or interpretation is merely an activity, perhaps only a very partial and surface activity, of the consciousness already and always inherent in the “personality”. Even if there 
were no impact of forces and no reactions, the consciousness would still be there, but static and inactive. But again this activity of consciousness might not be limited to an interpretation or a passive reaction to forces; it might also, if it chose, be the creator or determinant of its reactions – as for instance to a blow on the body or the vital it might refuse the natural reactions of pain or anger and remain still and immobile or it might return an unusual reaction of love or pleasure. Also this consciousness might not be only a recipient and seer of forces, but a creator or putter out of forces – it might be not only a knower, but an energy, a dynamis. In this view, your definition becomes totally inadequate. Farther, the word personality is misleading; for what we usually know as personality is itself only a formation of consciousness. Behind it we are aware of a Person or Purusha who puts forward the mutable surface formation we call personality and who may even have many personalities at a time or different personalities at different times. This Purusha would be then a being and consciousness, would be not a result or an activity, but a constant reality, an intrinsic power of awareness and action inherent in the being,– as the being is self-existent, so the consciousness self-existent in the being, the Purusha. This is the realisation we have of it in Yogic experience, eternal reality of consciousness inherent in the eternal reality of existence, as in the concept and experience of Sachchidananda.
This is the crucial point in the question, what is consciousness, whether it is a temporary phenomenon of Nature or a reality in itself fundamental to existence. The first is the conclusion that is drawn, and must be drawn, from normal experience on the surface. The other is at best a metaphysical speculation or an instinctive feeling in humanity unless we go beyond the normal experience, deepen and widen the range of our present consciousness and test its inner depths and inferior abysses and supernormal heights, until we can touch its fundamental or its ultimate or its total reality as is done in Yoga. To judge from only normal and superficial experience as the ordinary mind does with phenomena is to miss the truth of things – we have to go behind the surface phenomenon to find the reality of what a 
thing is. There are no gradations of consciousness if the ordinary phenomenon of consciousness is taken, unless perhaps we distinguish two gradations, the animal and the human; the differences created by the variations of subjective personality amount only to degrees of power of the same human-animal consciousness, a better or worse, cruder or more complex organisation of the instruments by which it receives or reacts to the contacts of Nature. If, on the contrary, consciousness is an inherent power of existence present even when it is not apparent to us or active on the surface, then we can conceive of it arranging its own manifestation in gradations which rise or fall between what seem to us now the subconscient depths and superconscient summits of existence.
The ordinary view of consciousness is based on normal superficial experience plus science. For physical science consciousness is a temporary phenomenon in an unconscious world, something evolved in an animate organisation that somehow develops in an originally inanimate and unconscious Matter. It is not inherent in life, for the plant has it not, it is rather a growing flicker that, once established, lasts intermittently through sleep and waking while life lasts and disappears with the dissolution of life. The ordinary mind identifies consciousness with human waking consciousness possibly shared by the animal – though that is not certain, for many refuse consciousness to the animal. A man is conscious while he lives, when he is dead consciousness disappears, when he is asleep, stunned, drugged, anaesthetised, in trance, then his consciousness is suspended; he is temporarily unconscious. How far is this scientific-superficial view correct or maintainable? For it raises two fundamental questions – is the waking surface consciousness the only form of consciousness possible? and again, is the consciousness synonymous with mind, is all consciousness mental or are other forms of it, supramental or submental, possible?