Consciousness is the result of a human intellect acting in conjunction with a human organisation; and if we withdraw or mutilate either element, we produce, not an actual man, but a hypothetical monster.
A being endowed, according to the hypothesis of Étienne Bonnot de Condillac, with a sense of smell only, and identifying himself with his successive sensations (it would be more correct to say having no notion of self at all), would not, properly speaking, be in any sense a conscious Icing. He would be deficient in the essential conditions of consciousness,, the distinction of subject from object, and of objects from each other.
To be conscious of a particular sensation we must know it as such; and to know it as such implies a concomitant knowledge of other sensations as different, and thus of the bodily organism as extended, or as occupying space. Much of what has been said of Space is applicable to Time also. This is the condition, not merely of external perception, but of the entire consciousness, external and internal alike.
Consciousness in every form implies a permanent and a variable element—a continuous self subject to successive modifications. It is thus necessarily manifested as a change, and that change as taking place in time. Pure time, like pure space, is not in itself an object of consciousness, but an element which, to be realised in consciousness, must be combined with the results of experience.
We can form no notion of time per se, with no events taking place in it. Time is thus manifested in the form of a relation of successive modes of consciousness to the one conscious self. It might be conjectured with some plausibility that a being not subject to any change of consciousness, or, on the other hand, one not cognisant of his personal identity in the midst of change, would have no idea of time. But then such a being would have no consciousness at all in the proper sense of the term.
Time, like space, cannot be annihilated by any act of thought, and cannot be conceived as subject to any limitation, as having either beginning or end, or as absent from any mode of consciousness. Indeed, these conditions mutually imply each other; for to conceive a limit of time would be to conceive a consciousness in which time is present, preceded or followed by another from which time is absent. Time has thus, in common with space, the characteristics of universality and necessity, which appear to indicate a subjective condition, or law of consciousness itself.
Like space, too, it is manifested in conjunction with and on the occasion of experience, being presented simultaneously with the empirical element of change, the apprehension of which constitutes the first step of positive consciousness. We are not at present concerned with the question whether space and time have any real existence apart from that of the mind which gives these forms to the objects of its consciousness.
***Excerpt from Henry Longueville Mansel, B.d.. Metaphysics or the philosophy of consciousness