Suppose that three sensations follow one another—first A, then B, then C. When this happens to you, you have the experience of passing through the process ABC. But note what this implies. It implies that there is something in you which stands sufficiently outside A to notice A passing away, and sufficiently outside B to notice B now beginning and coming to fill the place which A has vacated; and something which recognizes itself as the same through the transition from A to B to C, so it can say ‘I have had the experience ABC’. Now this something is what I call Consciousness or Soul and the process I have just described is one of the proofs that the soul, through experiencing time, is not itself completely ‘timeful’. The simplest experience of ABC as a succession demands as a soul which is not itself a mere succession of states, but rather a permanent bed along which these different portions of the stream of sensation roll, and which recognizes itself as the same beneath them all. Now it is almost certain that the nervous system of one of the higher animals presents it with successive sensations. It does not follow that it has any ‘soul’, anything which recognizes itself as having had A, and now having B, and now marking how B glides away to make room for C. If it had no such ‘soul’, what we call the experience of ABC would never occur. There would, in philosophic language, be ‘a succession of perceptions’; that is, the sensations would, in fact, occur in that order, and God would know that they were so occurring, but the animal would not know. There would not be ‘a perception of succession’. This would mean that if you give such a creature two blows with a whip, there are, indeed, two pains: but there is no coordinating self which can recognize that ‘I have had two pains’. Even in the single pain, there is no self to say ‘I am in pain’—for if it could distinguish itself from the sensation—the bed from the stream—sufficiently to say ‘I am in pain’, it would also be able to connect the two sensations as its experience.  

The Problem of Pain - C.S. Lewis