For the past couple of years I’ve been studying logic in order to sharpen my mind, appraise arguments, and help me develop arguments of my own. I’ve also been slowly marching through the works of C.S. Lewis. While these two topics were formerly unrelated, they both converged last year as I read Lewis’s book Miracles

I was so pleasantly surprised to learn that Lewis not only speaks positively of logic and reason, he uses reason to propose an impressive argument against philosophical naturalism (a philosophy that says matter is all there is) and even put forth a positive argument for the existence of God which has come to be known as the Argument from Reason. 

Lewis is known as “The Romantic/Rationalist” and for good reason. In Miracles he uses interesting analogies infused with razor sharp logic to help us understand the relationship between God and Reason. As philosopher Victor Reppert has noted, Lewis’s Argument from Reason is actually several different arguments. One of my favorites is when he uses water lilies to expound the relationship between God and Reason: 

“In a pond whose surface was completely covered with scum and floating vegetation, there might be a few water lilies. And you might of course be interested in them for their beauty. But you might also be interested in them because from their structure you could deduce that they had stalks underneath which went down to roots in the bottom. The Naturalist thinks that the pond (Nature – the great event in space and time) is of an indefinite depth- that there is nothing but water however far you go down. My claim is that some of the things on the surface (i.e. In our experience) show the contrary. These things (rational minds) reveal, on inspection, that they at least are not floating but attached by stalks to the bottom. Therefore the pond has no bottom. It is not pond, pond for ever. Go deep enough and you will come to something that is not pond- to mud and earth and then to rock and finally the whole bulk of Earth the subterranean fire.” (Miracles, pg. 45) 

Man, I love that! There’s a beautiful lily pad covered marsh that I drive past just about every day and since reading this passage last year, I’m constantly reminded of the relationship between God and Reason. 

Lewis’s water lily analogy is very similar to Cornelius Van Til’s “floorboards and beams” analogy, another one of my favorites. Van Til talks about how even though we don’t see the beams beneath the floorboards, the fact that we’re standing on the floorboards presupposes that there must be beams holding the house up.

Both analogies are types of transcendental arguments rather than direct arguments. Instead of seeking to move directly from A to B to C, the transcendental method says that A is a given, it’s an immediately known fact, or incorrigible belief, or necessary aspect of human experience or thought. Philosopher, Dr. James Anderson, says, “If there is any consensus on the nature of the transcendental premise, it is that the premise must at least express a necessary condition of some essential feature of human thought or experience” (James Anderson, No Dilemma for the Proponent of TAG, Philosophia Christi 13:1). 

So given A, what must be true in order for A to exist, what are the necessary preconditions of A. This method is a presuppositional method, we are looking at the presuppositions of a given, in this case A. So if A presupposes B, then the existence of A means that B must necessarily exist. 

So to bring it back to the water lily analogy, if we see the surface portion of the plant, i.e. the lily pad or colorful flower, we can infer that there’s a stem that’s anchoring the plant to the bottom of the pond. A healthy water lily plant presupposes a stem and roots. Likewise, when it comes to reason, if it exists, then it’s preconditions necessarily exist. Lewis makes a compelling argument that God is the necessary precondition of Reason, so that if Reason exists God must exist. 

P1. reason presupposes God 
P2. reason necesarrily exists
C. therefore, God necesarrily exists.

Here’s Lewis’s explanation:

“We have seen that rational thought is not part of the system of Nature. Within each man there must be an area (however small) of activity which is outside or independent of her. In relation to Nature, rational thought goes on ‘of its own accord’ or exists ‘on its own’. It does not follow that rational thought exists absolutely on it’s own. It might be independent of Nature by being dependent on something else. For it is not dependence simply but dependence on the non-rational which undermines the credentials of thought. One man’s reason has been led to see things by the aid of another man’s reason, and is none the worse for that. It is thus still an open question whether each man’s reason exists absolutely on its own or whether it is the result of some (rational) cause- in fact, of some other Reason. That other Reason might conceivably be found to depend on a third, and so on; it would not matter how far this process was carried provided you found Reason coming from Reason at every stage. It is only when you are asked to believe in Reason coming from non-reason that you must cry Halt, for, if you don’t, all thought is discredited. It is therefore obvious that sooner or later you must admit a Reason which exists absolutely on its own. The problem is whether you or I can be such a self-existent Reason…. what exists on its own must have existed from all eternity; for if anything else could make it begin to exist then it would not exist on its own but because of something else. It must also exist incessantly: that is, it cannot cease to exist and then begin again. For having once ceased to be, it obviously could not recall itself to existence, and if anything else recalled it it would then be a dependent being. Now it is clear that my Reason has grown up gradually since my birth and is interrupted for several hours each night. I therefore cannot be that eternal self-existent Reason which neither slumbers nor sleeps. Yet if any thought is valid, such a Reason must exist and must be the source of my own imperfect and intermittent rationality. Human minds, then, are not the only supernatural entities that exist. They do not come from nowhere. Each has come into Nature from Supernature: each has its tap-root in an eternal, self-existent, rational Being, whom we call God. Each is an offshoot, or spearhead, or incursion of that Supernatural reality into Nature.” (Miracles pg. 41-43). 

If Lewis’s argument holds, then just as we can infer from a healthy waterlily, a stem and roots, so we can also infer from the existence of rational inference that Reason exists, i.e. God exists.