Why Rational Thought Destroys ‘Lack of Belief’ Atheism and Points to God

“In the beginning was the Word (λόγος, Logos), and the Word was with God, and the Word was God.” (John 1:1, ESV)

The Argument from Reason asserts that human rationality—our capacity for logic, abstract thought, and truth recognition—can only be explained by the existence of God. This argument, championed by thinkers such as C.S. Lewis, Alvin Plantinga, and Victor Reppert, demonstrates that reason cannot emerge from non-rational, material processes but requires a transcendent rational source. However, many atheists today redefine atheism as a mere “lack of belief” rather than a proposition about reality. This shift is often presented to avoid the burden of proof. Yet, this redefinition collapses under scrutiny, as it renders atheism an irrationally passive state that cannot engage in meaningful discourse about truth, reason, or reality.

The confusion begins with a failure to define terms properly. Belief is a mental state that involves accepting a proposition as true or likely true. Beliefs can be either affirmative (“X is true”) or negative (“X is false”). A proposition is a declarative statement that can be either true or false, making it subject to rational debate. Traditional atheism, or “classical atheism,” is the proposition that no gods exist. Agnosticism, by contrast, is the position of not knowing whether any gods exist—a suspension of belief rather than a claim. In contrast, “weak atheism” or “lack of belief” atheism is not a proposition but a psychological state, expressing no claim about reality. The Stanford Encyclopedia of Philosophy clarifies:

“Atheism is the proposition that God does not exist … not merely the absence of belief.” (Stanford Encyclopedia of Philosophy, Atheism and Agnosticism)

If atheism is defined solely as a “lack of belief,” it cannot be a rational position, as it is a psychological description rather than a propositional stance. Only propositions can be debated rationally. Greg Koukl emphasizes this when he writes:

“Only propositions can be true or false; psychological states cannot” (Tactics).

A belief is a propositional attitude—it accepts or rejects a claim—while a lack of belief is a psychological state with no propositional content. As a result, atheism defined solely as “lack of belief” cannot engage in rational debate, as it makes no claim and carries no burden of proof. Without making an assertion, it collapses into intellectual passivity. Imagine someone saying, “I lack belief that gravity exists” without providing reasons or an alternative explanation for physics. They are not engaging rationally; they are avoiding engagement altogether.

Moreover, the “lack of belief” definition creates a fallacy of asymmetric burdens. Some atheists argue that theists bear the full burden of proof because they are making a positive claim, while atheists, by merely “lacking belief,” are exempt from justification. However, rational discourse requires symmetrical accountability. William Lane Craig rightly observes:

“The claim ‘there is no God’ is every bit as much a claim to knowledge as ‘there is a God’” (Reasonable Faith).

Even the statement, “I am unconvinced,” is a claim about the insufficiency of evidence—an epistemic claim—and implies a judgment about the improbability of God’s existence, which carries its own burden of justification. Rational engagement requires more than passive disbelief; it demands a reasoned stance.

Furthermore, those who claim to “lack belief” often smuggle in an alternative worldview—usually naturalism—without admitting it. Naturalism, the view that nature is all that exists and everything can be explained by natural processes, is not a neutral default. It is a proposition that requires defense. Naturalism implies materialism (the belief that only the physical world exists) and empiricism (the belief that only sensory or scientific evidence is reliable). Yet these are positive claims, not absences of belief. Every worldview, including naturalism, has explanatory burdens. “Lack of belief” atheism often functions as a rhetorical shield, concealing a commitment to naturalism without having to justify it.

The Argument from Reason exposes why naturalism, often the hidden foundation of “lack of belief” atheism, fails to account for human rationality. Reason requires a non-material foundation because logical laws, such as the law of non-contradiction, are immaterial, universal, and necessary truths. Materialism cannot produce immaterial laws. Blind physical processes—like chemical reactions—cannot yield intentionality or aboutness, the property of thoughts being directed toward something. Philosopher John Searle states:

“You cannot get intentionality from blind physical processes” (Intentionality).

Materialism reduces thoughts to brain chemistry, but chemicals follow physical laws, not logical principles. Additionally, evolution prioritizes survival, not truth. Natural selection selects for behaviors that promote survival, not necessarily beliefs that are true. False beliefs can often be adaptive. For example, superstitions might help primitive humans avoid dangers, even if the beliefs themselves are false. Alvin Plantinga argues:

“If our cognitive faculties have developed solely under the pressures of natural selection, the probability that they are reliable is low” (Warrant and Proper Function).

If naturalism is true, we would have no reason to trust our cognitive faculties, as they would be the product of survival-driven, not truth-driven, processes. Yet we do trust our reasoning, especially in fields like science and mathematics. This trust in our reasoning becomes irrational if naturalism is true, as naturalism undermines its own reliability.

A Bayesian analysis further highlights the weakness of naturalism. Bayesian probability compares how well different worldviews explain an observed fact—in this case, reliable reasoning. The probability of reliable reasoning under naturalism and evolution, P(R|N&E), is low because evolution selects for survival, not truth. By contrast, the probability of reliable reasoning under theism, P(R|T), is high, since theism posits a rational Creator whose image we bear. Therefore, by Bayes’ theorem:

• P(T|R) > P(N|R) (Theism is more probable than Naturalism, given reliable reason).

Atheists may respond with objections, but these objections fail under scrutiny. Some claim that “lack of belief” is simply the default position. However, the true default position is agnosticism—a suspension of judgment—not atheism, which is a rejection of the theistic claim. Moreover, defaults are not destinations; they are starting pointspending further inquiry. Babies lack belief in quantum physics, but that does not make them quantum physicists. Others argue that they do not need to disprove God, only reject theistic arguments. Yet rejecting theistic arguments involves making propositional claims about:

• The validity of logic (epistemology)
• The nature of reality (ontology)
• The limits of evidence (methodology)

These are not neutral refusals but positive claims requiring justification. Additionally, some atheists argue that Christians also “lack belief” in other gods. However, Christians do not merely lack belief; they positively reject other gods based on historical, philosophical, and theological reasons. Christianity makes exclusive truth claims supported by evidence; it is not a position of passive non-belief but of reasoned belief.

A strong analogy can illustrate the fallacy of “lack of belief” as a defense. Imagine a courtroom trial where the prosecution asserts:

“God exists beyond reasonable doubt.”

The defense responds:

“We lack belief.”

The judge asks:

“Do you dispute the evidence or propose an alternative explanation?”

The defense replies:

“No, we just lack belief.”

The verdict would be simple:

“Then the prosecution stands unopposed. Case closed.”

Rational discourse demands reasons, not passivity. Without a counter-case, the defense loses by default. Similarly, atheism defined as “lack of belief” is intellectual evasion.

Scripture affirms the necessity of reason and the impossibility of escaping accountability for one’s beliefs. John 1:1 declares:

“In the beginning was the Word (λόγος, Logos),” presenting God as the source of logic and rationality.

Isaiah 1:18 records God’s invitation to reason:

“Come now, let us reason together.”

Paul in Romans 1:20 states that God’s nature is:

“clearly seen” through creation, so people are “without excuse.”

Proverbs 1:7 teaches that:

“The fear of the Lord is the beginning of knowledge,” affirming that true wisdom is grounded in God.

The biblical worldview positions reason not as a human invention but as a reflection of God’s rational nature.

The Argument from Reason reveals why “lack of belief” atheism is an intellectually evasive and philosophically incoherent position. Rational debate requires propositions, and “lack of belief” is not a proposition but a psychological state. Atheists who hide behind “lack of belief” still make implicit claims about evidence, reality, and reason, all of which carry burdens of proof. Naturalism, the worldview typically underlying atheism, fails to explain human rationality, as it reduces thought to chemical processes and undermines trust in reason. Theism, by contrast, provides a coherent foundation for reason: a rational Creator whose image we bear. Bayesian probability confirms that reliable reasoning is more probable under theism than under naturalism.

The final syllogism against “lack of belief” atheism is clear:

• Rational debate requires propositions—claims that can be true or false.
• A belief is a propositional attitude toward a truth claim.
• “Lack of belief” is a psychological state, not a proposition.
• Therefore, “lack of belief” is epistemically passive, not a rationally justified position.
• Rational engagement requires justifying one’s epistemic stance—affirmation, negation, or agnosticism.
• Hence, “lack of belief” atheism is intellectually evasive and cannot compete in rational discourse.

The Argument from Reason for Theism stands firm:

• If naturalism is true, reason results from blind, non-rational processes.
• Blind, non-rational processes cannot produce reliable reasoning.
• Yet we possess reliable reasoning (as evidenced by science, logic, and mathematics).
• Therefore, naturalism is false.
• The best explanation for reason is a rational, transcendent Mind—God.

C.S. Lewis stated:

“Unless human reasoning is valid, no science can be true. If it undermines itself, all thought is discredited” (Miracles).

---

A Challenge to the Reader:

If reason exists, can you deny the Logos behind it? If rational thought requires a rational source, can you deny the God from whom all reason flows? You may “lack belief” in God, but can you justify belief in your reason without Him?

---

Endnotes:

1. C.S. Lewis, Miracles.
2. Alvin Plantinga, Warrant and Proper Function.
3. Greg Koukl, Tactics.
4. John Searle, Intentionality.
5. Thomas Nagel, Mind and Cosmos.
6. Antony Flew, There Is a God.
7. William Lane Craig, Reasonable Faith.
8. Stanford Encyclopedia of Philosophy, Atheism and Agnosticism.