Here is the most powerful version of this argument, not the popular version, not the straw man, but the version a careful philosopher would give you. Every event you have ever observed has a prior physical cause. The neurons firing as you read this sentence were caused by prior electrochemical states, which were caused by prior molecular configurations, which were caused by prior physical conditions, tracing backward through an unbroken physical chain to the Big Bang, and perhaps before. At no point in that chain has anyone inserted a non-physical cause and found that it explained anything. Naturalism is not an assumption. It is a description of the only causal framework that has ever successfully explained anything.
I. Causal Closure: The Technical Claim
The principle of causal closure states: every physical event has a sufficient physical cause. This is not a claim that non-physical things do not exist. It is a claim that if they do, they have no causal power over the physical world. A God who creates but never causes any physical event is, by definition, causally irrelevant, and therefore scientifically untestable and practically indistinguishable from a God who does not exist.
David Papineau, who has written extensively on physicalism, states the principle carefully: causal closure is supported by the success of physics. Every time we have traced a physical process back to its causes, we have found physical causes. The expanding sphere of physics has absorbed biology, chemistry, neuroscience. each field's "vital forces" and "mental powers" eventually dissolved into physical mechanism. The burden of proof lies with whoever claims a cause that falls outside this pattern.
II. Methodological vs. Metaphysical Naturalism
Here is where the argument becomes philosophically crucial, and where the naturalist often conflates two very different claims. Methodological naturalism says: in doing science, we proceed as if physical causes explain physical events. This is a research strategy, and it is enormously successful. Metaphysical naturalism says: physical causes are all that exist. This is a philosophical claim about reality, not a finding of science.
The move from methodological to metaphysical naturalism is not a scientific inference. It is a philosophical commitment made in advance, and it is not self-evident. Alvin Plantinga's argument is pointed: if naturalism is true, then our cognitive faculties were shaped by natural selection for survival, not truth-tracking. But then we have no reliable grounds for believing naturalism itself to be true. The argument that produces naturalism undermines the reliability of the argument that produced it.
III. The Origin of the Causal Chain
Causal closure, even if granted within the universe, does not address the origin of the physical universe itself. The causal closure principle applies to events within spacetime. But the Big Bang, the origination of spacetime, matter, and energy, is not an event within the causal chain. It is the beginning of the chain.
Stephen Hawking and Leonard Mlodinow wrote in The Grand Design (2010): "Because there is a law such as gravity, the universe can and will create itself from nothing." The sentence contains a fatal ambiguity. Laws of physics are not nothing. The question of why physical laws exist, why they have the form they have, and why they apply rather than something else, is precisely the question that naturalism, by design, cannot answer. You cannot use the laws to explain the laws without circularity.
IV. The Information Problem Naturalism Cannot Touch
Naturalism is a theory about physical causation. Information is not a physical quantity. Shannon entropy, the formal measure of information, is defined independently of any physical substrate. The same information can be encoded on paper, in magnetic domains, in DNA base pairs, in transistor states. The physical substrate changes. The information does not.
This is the crack in the naturalist foundation that widens with every advance in biology. The cell is not merely a chemical system. It is an information-processing system. The distinction is not semantic; it is the distinction between a pile of metal and a running program. Causal closure explains the hardware. It does not explain the software. And in biology, the software is primary: DNA does not cause protein synthesis the way a physical object causes motion. It instructs it. Instruction is not a physical relationship.
Paul Davies writes in The Fifth Miracle: "Living systems are not just complex chemical machines. They process information in ways that have no analogue in non-living chemistry." The naturalist has no account of how physical processes generate the semantic content of biological information, only its physical vehicle.
V. The NOW Counter: What Naturalism Requires You to Accept
If naturalism is true, consider what it requires you to accept without complaint: the universe came into being from nothing by no cause; physical laws exist with no explanation for their form or existence; 26 fundamental constants are set to life-permitting values by no agency; matter spontaneously organized into self-replicating digital-information-processing systems by processes no one has successfully demonstrated; and you, the reader, are a configuration of particles who has somehow developed the capacity to evaluate these claims and ask whether they are true, by a process that was optimized for survival, not for truth.
That is not a description of a world with no explanation. That is a description of a world with an explanation naturalism refuses to consider.
Naturalism Assumes What It Cannot Explain
The physical laws that naturalism invokes to explain the universe did not exist before the universe existed. The information that biology requires is not a physical quantity. The origin of the causal chain demands a cause outside the chain, by the logic of causation itself. That is not a religious claim. It is a philosophical one. And the philosophical evidence converges with the historical evidence on the same Person.
The Information Case: DNA & the Coder →The following sources constitute the primary intellectual foundations for reviewing and preparing for this kind of argument.
- Papineau, D. (1993). Philosophical Naturalism. Blackwell. The clearest contemporary statement of causal closure and its implications for mind and causation. Search this source ↗
- Plantinga, A. (1993). Warrant and Proper Function. Oxford University Press. The evolutionary argument against naturalism — Plantinga's case that naturalism is self-defeating. Search this source ↗
- Davies, P. (1998). The Fifth Miracle: The Search for the Origin and Meaning of Life. Simon & Schuster. Davies argues that living systems are fundamentally information-processing systems — a problem naturalism cannot solve by chemistry alone. Search this source ↗
- Craig, W.L. & Sinclair, J.D. (2009). "The Kalam Cosmological Argument." In The Blackwell Companion to Natural Theology. The philosophical case that the universe began to exist and therefore has a transcendent cause. The most rigorous contemporary formulation of cosmological argument. Search this source ↗
Where Does This Argument Lead You?
Select the conclusion that most honestly fits your assessment.