In C. S. Lewis’ book Miracles, he approaches the question of how far our reason can go, and what would happen if all that exists is matter and energy. Nowdays we are told by the modern secularist and atheist that we should pay no attention to anything unless it be the product of natural causes; that supernatural causes do not exist. Even those who are not radical atheists often live as though nothing supernatural has ever happened, or ever will. Lewis slices this view with a very sharp knife:
We may in fact state as a rule that no thought is valid if it can be fully explained as the result of irrational causes. . . If you even suspect an irrational cause, you begin to pay less attention to a man’s beliefs; your friend’s pessimistic view of the European situation alarms you less when you discover that he is suffering from a bad liver attack. Conversely, when we discover a belief to be false we then first look about for irrational causes (“I was tired” — “I was in a hurry” — “I wanted to believe it”). . . Because [a man] thinks that my thoughts result from an irrational cause he therefore discounts them. All thoughts which are so caused are valuless. We never, in our ordinary thinking, admit any exceptions to this rule.
Now it would clearly be preposterous to appply this rule to each particular thought as we come to it and yet not to apply it to all thoughts taken collectively, that is, to human reason as a whole. Each particular thought is valueless if it is the result of irrational causes. Hence every theory of the universe which makes the human mind a result of irrational cuases is inadmissible . . .
But Naturalism, as commonly held, is precisely a theory of this sort. The mind, like every other particular thing or event, is supposed to be simply the product of the Total System. It is supposed to be that and nothing more, to have no power whatever of “going on its own accord.” And the Total System is not supposed to be rational. All thoughts whatever are the results of irrational causes, and nothing more than that. (Miracles, p.20-22)
If, as the atheists and cultural naturalists of today tell us, that we are to only consider the universe made up of matter and energy and nothing more, why then, it is made up of nothing more. This is why the thinking naturalists hold that humans have no free will, for if their view is true, there is no free molecule in the universe; all particles are behaving according to natural law and have no ‘mind’ of their own.
The problems then start to add up rather quickly. In the naturalistic viewpoint we have no explanation for how rationality has come from irrationality. We do not have free will, for no machine or chemical process can act of its own accord, but must follow the prescribed laws and rules, which, by the way, are all irrational natural forces with no purpose or design. Further, one of the atheists big criticisms of Christianity is the accusation that Christians are not rational, and that no Christian thought should be admitted since nothing exists in the world but random natural particles. But if all that exists are random natural particles, the reasons for questioning Christianity are founded on irrational processes, not on a mind reasoning through a question.
But it gets worse, as Lewis is driving us toward. If naturalism is true, then all rational thought is not possible, or at best some sort of illusion, one that we know does not exist. But such a concludion (that rational thought is not possible or an illusion) is a rational conclusion that we drew in our mind due to observing the world. We are driven very quickly into a position where we have to question every thought, how it could have arisen from some irrational natural process. But the very act of questioning our thoughts is supposed to be a rational act, and therefore is not possible under the naturalistic system. Thus naturalism, the view that says supernatural causes do not exist and we should question anything that is not rational, slits its own throat, and ends in very messy pile of irrationality. The only way our atheist friends can avoid such a problem is to somehow hold to rational thought in spite of their position that the world is totally irrational, a position which is not reasonable or tenable.
Much more rational is to conclude that there is indeed something in the unverse beyond matter and energy, a thing which is not natural, but which gives nature order and gives people rationality. And this we call God.