Miracles. C. S. Lewis

unit of matter (it would be rash to call it any longer a ‘particle’) moves in an indeterminate or random fashion; moves, in fact, ‘on its own’ or ‘of its own accord’. The regularity which we observe in the movements of the smallest visible bodies is explained by the fact that each of these contains millions of units and that the law of averages therefore levels out the idiosyncrasies of the individual unit’s behaviour. The movement of one unit is incalculable, just as the result of tossing a coin once is incalculable: the majority movement of a billion units can however be predicted, just as, if you tossed a coin a billion times, you could predict a nearly equal number of heads and tails. Now it will be noticed that if this theory is true we have really admitted something other than Nature. If the movements of the individual units are events ‘on their own’, events which do not interlock with all other events, then these movements are not part of Nature. It would be, indeed, too great a shock to our habits to describe them as super-natural. I think we should have to call them sub-natural. But all our confidence that Nature has no doors, and no reality outside herself for doors to open on, would have disappeared. There is apparently something outside her, the Sub-natural; it is indeed from this Subnatural that all events and all ‘bodies’ are, as it were, fed into her. And clearly if she thus has a back door opening on the Subnatural, it is quite on the cards that she may also have a front door opening on the Supernatural—and events might be fed into her at that door too.

      I have mentioned this theory because it puts in a fairly vivid light certain conceptions which we shall have to use later on. But I am not, for my own part, assuming its truth. Those who like myself have had a philosophical rather than a scientific education find it almost impossible to believe that the scientists really mean what they seem to be saying. I cannot help thinking they mean no more than that the movements of individual units are permanently incalculable to us, not that they are in themselves random and lawless. And even if they mean the latter, a layman can hardly feel any certainty that some new scientific development may not tomorrow abolish this whole idea of a lawless Subnature. For it is the glory of science to progress. I therefore turn willingly to other ground.

      It is clear that everything we know, beyond our own immediate sensations, is inferred from those sensations. I do not mean that we begin as children, by regarding our sensations as ‘evidence’ and thence arguing consciously to the existence of space, matter, and other people. I mean that if, after we are old enough to understand the question, our confidence in the existence of anything else (say, the solar system or the Spanish Armada) is challenged, our argument in defence of it will have to take the form of inferences from our immediate sensations. Put in its most general form the inference would run, ‘Since I am presented with colours, sounds, shapes, pleasures and pains which I cannot perfectly predict or control, and since the more I investigate them the more regular their behaviour appears, therefore there must exist something other than myself and it must be systematic’. Inside this very general inference, all sorts of special trains of inference lead us to more detailed conclusions. We infer Evolution from fossils: we infer the existence of our own brains from what we find inside the skulls of other creatures like ourselves in the dissecting room.

      All possible knowledge, then, depends on the validity of reasoning. If the feeling of certainty which we express by words like must be and therefore and since is a real perception of how things outside our own minds really ‘must’ be, well and good. But if this certainty is merely a feeling in our own minds and not a genuine insight into realities beyond them—if it merely represents the way our minds happen to work—then we can have no knowledge. Unless human reasoning is valid no science can be true.

      It follows that no account of the universe can be true unless that account leaves it possible for our thinking to be a real insight. A theory which explained everything else in the whole universe but which made it impossible to believe that our thinking was valid, would be utterly out of court. For that theory would itself have been reached by thinking, and if thinking is not valid that theory would, of course, be itself demolished. It would have destroyed its own credentials. It would be an argument which proved that no argument was sound—a proof that there are no such things as proofs—which is nonsense.

      Thus a strict materialism refutes itself for the reason given long ago by Professor Haldane: ‘If my mental processes are determined wholly by the motions of atoms in my brain, I have no reason to suppose that my beliefs are true … and hence I have no reason for supposing my brain to be composed of atoms.’ (Possible Worlds)

      But Naturalism, even if it is not purely materialistic, seems to me to involve the same difficulty, though in a somewhat less obvious form. It discredits our processes of reasoning or at least reduces their credit to such a humble level that it can no longer support Naturalism itself.

      The easiest way of exhibiting this is to notice the two senses of the word because. We can say, ‘Grandfather is ill today because he ate lobster yesterday.’ We can also say, ‘Grandfather must be ill today because he hasn’t got up yet (and we know he is an invariably early riser when he is well).’ In the first sentence because indicates the relation of Cause and Effect: The eating made him ill. In the second, it indicates the relation of what logicians call Ground and Consequent. The old man’s late rising is not the cause of his disorder but the reason why we believe him to be disordered. There is a similar difference between ‘He cried out because it hurt him’ (Cause and Effect) and ‘It must have hurt him because he cried out’ (Ground and Consequent). We are especially familiar with the Ground and Consequent because in mathematical reasoning: ‘A = C because, as we have already proved, they are both equal to B.’

      The one indicates a dynamic connection between events or ‘states of affairs’; the other, a logical relation between beliefs or assertions.

      Now a train of reasoning has no value as a means of finding truth unless each step in it is connected with what went before in the Ground-Consequent relation. If our B does not follow logically from our A, we think in vain. If what we think at the end of our reasoning is to be true, the correct answer to the question, ‘Why do you think this?’ must begin with the Ground-Consequent because.

      On the other hand, every event in Nature must be connected with previous events in the Cause and Effect relation. But our acts of thinking are events. Therefore the true answer to ‘Why do you think this?’ must begin with the Cause-Effect because.

      Unless our conclusion is the logical consequent from a ground it will be worthless and could be true only by a fluke. Unless it is the effect of a cause, it cannot occur at all. It looks therefore, as if, in order for a train of thought to have any value, these two systems of connection must apply simultaneously to the same series of mental acts.

      But unfortunately the two systems are wholly distinct. To be caused is not to be proved. Wishful thinkings, prejudices, and the delusions of madness, are all caused, but they are ungrounded. Indeed to be caused is so different from being proved that we behave in disputation as if they were mutually exclusive. The mere existence of causes for a belief is popularly treated as raising a presumption that it is groundless, and the most popular way of discrediting a person’s opinions is to explain them causally—‘You say that because (Cause and Effect) you are a capitalist, or a hypochondriac, or a mere man, or only a woman’. The implication is that if causes fully account for a belief, then, since causes work inevitably, the belief would have had to arise whether it had grounds or not. We need not, it is felt, consider grounds for something which can be fully explained without them.

      But even if grounds do exist, what exactly have they got to do with the actual occurrence of the belief as a psychological event? If it is an event it must be caused. It must in fact be simply one link in a causal chain which stretches back to the beginning and forward to the end of time. How could such a trifle as lack of logical grounds prevent the belief’s occurrence or how could the existence of grounds promote it?

      There seems to be only one possible answer. We must say that just as one way in which a mental event causes a subsequent mental event is by Association (when I think of parsnips I think of my first school), so another way in which it can cause it, is simply by being a ground for it. For then being a cause and being a proof would coincide.

      But this, as it stands, is clearly untrue. We know by experience that a thought does not necessarily