Another Dangerous Idea

The Conflict of Ideas

This post is a review of C.S. Lewis’s Dangerous Idea, by Victor Reppert, and a discussion of the ideas in it.

Victor Reppert wrote this book in 2003.  My impression is that the title is primarily a marketing decision.  It is intended to call to mind the title of Daniel Dennett’s criticism of theism in his Darwin’s Dangerous Idea.  Dennett thought Darwinism was “dangerous” to theism because it suggests the possibility that material things can have purely natural, or material, origins.

Reppert also invokes C.S. Lewis, to balance the philosophical firepower but also to suggest that the so-called “argument from reason” is dangerous to anti-theism (or “materialism,” or “naturalism”) in the same way.  Reppert is suggesting that the very process of deliberating on the truth of naturalism and super-naturalism undermines the materialist position.   Reppert draws out C.S. Lewis’s take on the subject from his (Lewis’s) book Miracles, in particular its revised form following Lewis’s famous debate on the subject with Elizabeth Anscombe.


Let’s start with this.  It is often argued that the very fact of order in the universe implies the existence of an order-Giver.  All of science presupposes the existence of this order.  In fact, science would be impossible without it.  Science assumes that there are constant and measurable forces acting upon physical things in predictable ways.  The undeniable order of the universe has huge implications for the question whether or not God is.  As C.S. Lewis wrote:


Men became scientific because they expected Law in Nature, and they expected Law in Nature because they believed in a Legislator.


It has often been argued that Christianity provided the intellectual foundation for all of science, including its breakout in the early Enlightenment with Francis Bacon, Isaac Newton, and so on. Christianity provided this foundation because Christians envisioned a God of order, who created material reality in a state of order.

If there is no God, however, then all of reality consists of matter in motion. A person who believes there is no God is a materialist; a naturalist; an anti-theist or atheist; one who rejects metaphysics. This is the dominant view of reality in our culture, and the point of view people necessarily adopt when they shrug the shoulders and ask “who knows” when considering the proposition that God is.

If all of reality is natural reality, how does that vision of reality explain the obvious order of the universe? The short answer, for theists, is that it doesn’t. Materialism depends on the existence of that order, but cannot explain it.

Rational Inference

Now with that background, we can go a step forward with these ideas, and consider the “argument from reason,” as it is stated in its usual philosophical formulation, or, as Reppert (and I) prefer, “the argument from rational inference.”

The basic idea is this. We develop our ideas about the truth of materialism, or theism, or anything else, for that matter, by making logical inferences. One observation leads us to another logically. We say it’s “logical” because we say one inference causes the next. That causation is at the heart of the order of the universe. Our reasons for our beliefs – and our reasons for everything – are based on a sometimes complex series of inferences, from observations to ideas to ideas. That progression is not random.

Negation of Materialism

The argument from rational inferences serves not just to support theism but to negate materialism. Materialism is self-defeating because it requires refutation of the very argument it attempts to advance.

It goes like this. First, a belief is not rationally inferred if it can be fully explained by non-rational causes. A non-rational cause includes any cause that is not the product of thought. So B can follow A naturally and in accordance with the natural order of the universe, but not be “rational” because it is not the product of rational thought.

If materialism is true, then all beliefs can be fully explained by nonrational causes. It rests on the determinist principle that one’s thoughts are the products of a seemingly infinite (but actually finite) number of movements of matter according to natural forces, from the largest galaxy to the smallest nearly imperceptible spark in the brain. One’s thought at any moment is the result of physical causes and effects, only.

If materialism is true, then no belief is arrived at from causes other than physical ones. They are determined mechanistically; not rationally inferred. A person’s beliefs are not formed by a series of rational inferences, but instead by the particular combination of material particles in motion to the moment the belief is formed. That person’s belief is formed purely by mechanistic processes, not by rational inferences.

On one level this just sounds like a reiteration of the notion that the appearance of logic and order within natural reality implies an ordering Entity. But it also applies to our individual consciousness. The existence of rational inferences experienced subjectively would appear to be among the most basic of our beliefs about reality. To deny them runs counter to our very sense of subjective directedness – the “aboutness” of our consciousness, its intentionality. How can we exist as meat machines and organic calculators, when we have this deep intuition that inside our minds we make rational inferences from observation to idea, or idea to idea? We employ rational inferences even to discern the truth or falsity of the proposition that rational inferences explain reality.

The Mind of God

The materialist explanation of reality rejects that proposition, and therefore must itself be rejected. The proposition (that people explain reality through a series of rational inferences) is supported not only by subjective conscious experience, but by the logical connections extant in the physical world around us. Those logical connections are the same kind of logical connections we make internally; rationally. The conclusion is that there is a rational, thought-connection between events in the physical world. We live inside the mind of God.

Scientific Fideism

“Fideism” is the idea that our belief is based on faith alone; that science, philosophy, and rational thought in general are irrelevant to faith. People rightly scoff at the fideist’s justification for belief. Faith should be based on natural revelation, including but not limited to supernatural revelation. These are matters which present to our reason.

And yet, the usual method of persuasion to materialism is that we’re to accept on faith that materialism explains or will explain everything, and so if there’s anything not yet explained materialistically, we’re to nonetheless remain faithful to materialism. This is “promissory materialism;” a priori commitment to the anti-metaphysical proposition. This might be called scientific fideism. It must be rejected for the same reason as Christian fideism.

The Dangerous Idea

So what’s so dangerous about the argument from rational inferences? It jeopardizes the coherence of the naturalist worldview. Whether you’re a committed materialist, or just a materialist by default, the very reasoning by which we arrive at truth calls that naturalistic or materialistic worldview into question. According to C.S. Lewis and Reppert:

If we explain reason naturalistically we shall end up explaining it away, that is, explaining it in such a way that it cannot serve as a foundation for the natural sciences that are themselves the foundation for naturalism.






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