Let us suppose, for instance the existence of a being, furnished with human organs of sensation, but with no power of remembering or reflecting upon the objects presented to them, and no continuance of any impression beyond the moment of its actual presence. It is probable that, in such a case, though diverse objects might be successively presented to the senses, yet there would be no consciousness of their diversity; for such consciousness requires the juxtaposition of the objects in the mind, and this can only be effected by memory.
Animals, trees, and stones, might be successively placed before his eyes. Pleasure and pain and fear and anger might possibly take place within him; but as each departed, he would have no knowledge that it had ever existed, and consequently no power of comparison with anything else. He would thus have no distinct consciousness of each object as referred to a separate notion: he could not say, this which I see is a tree or a stone; this which I feel is fear or anger.
His consciousness, if consciousness it could be called, would probably be no more than an indefinite sense of uneasiness, a feeling of momentary irritation in the organ affected, but without discerning in what manner it is affected, and without distinguishing the permanent self from its momentary affection.
This is the lowest degree of intelligence, the germ of consciousness, but not itself entitled to the name; as being deficient in the essential conditions of limitation and difference, not having realised the distinction between subject and object, or between one object and another. But let us go one step further, and suppose the same being to be capable, not merely of receiving, but of retaining and associating together various impressions, though still destitute of the power of reflecting upon them.
***Excerpt from Henry Longueville Mansel, B.d.. Metaphysics or the philosophy of consciousness