Circular Reasoning
Using the conclusion of an argument as one of its premises, so that the argument only works if you already accept what it is trying to prove. The classic theological form: 'The Bible is true because God wrote it, and God wrote it because the Bible says so.'
Source: Aristotle, Prior Analytics (c. 350 BCE) – Public Domain
Also known as: Circular Logic, Begging the Question, Petitio Principii, Vicious Circle
Circular reasoning (also called begging the question, petitio principii) is a formal logical fallacy in which the conclusion of an argument is used, directly or indirectly, as one of its premises. The argument is logically valid in form but epistemically empty — it provides no actual evidence for the conclusion because the conclusion is already assumed in the support for it. The circle may be tight ('A because A') or elaborate, with many steps before returning to the starting point.
Circular reasoning is one of the most nuanced fallacies in theological epistemology because there is a sophisticated tradition that defends a version of circularity as unavoidable when reasoning about ultimate foundations. The presuppositionalist tradition (associated with Cornelius Van Til, Greg Bahnsen, and others) argues that all worldviews are ultimately circular at the foundational level — the naturalist assumes naturalism in assessing evidence for miracles, the rationalist assumes the reliability of reason in validating reason, and the Christian assumes the authority of Scripture in interpreting experience. On this view, circular reasoning at the foundational level is not a fallacy but an inescapable feature of first-principle reasoning.
This is a serious philosophical observation, but it should not be confused with the common, fallacious form of circular reasoning that appears in apologetics and popular theology. When someone claims that we know the Bible is historically reliable because it says it was inspired by God, and we know it was inspired by God because it is historically reliable, they have not engaged the epistemological question at all — they have built a rhetorical enclosure that feels like it has an inside and an outside but actually admits no external evidence.
The distinction that matters is between a transcendental argument (showing that some framework is the necessary precondition for making sense of experience) and a simple loop (using the conclusion to support the premises that lead to the conclusion). The presuppositionalist is making the former; the common theological circle is often making the latter without knowing it.
- 1The support offered for a claim turns out, on examination, to assume the claim itself
- 2When asked 'Why do you believe X?', the answer ultimately reduces to 'Because X is true'
- 3The argument feels persuasive only to those who already accept the conclusion
- 4External evidence is dismissed on grounds that require accepting the conclusion first — 'Archaeology can't contradict the Bible because the Bible is infallibly true'
- 5The chain of reasoning returns to its starting point after two or more steps without having added any new evidence
The circularity question is pressing for Christian epistemology because the Bible's self-witness (2 Timothy 3:16, 2 Peter 1:20-21) is one of the evidences cited for its divine authority — and citing a text in support of its own authority looks circular. This is a genuine challenge that has occupied theologians from Augustine through Aquinas to the Reformers and into contemporary analytic philosophy of religion. The sophisticated responses involve pointing to the convergence of multiple independent lines of evidence (textual transmission, historical corroboration, internal coherence, theological depth, transformative effect, archaeological confirmation) and to the argument that some framework must serve as foundational — the question is which framework is most warranted, not whether circularity at some level is avoidable. The fallacy lies in treating the circular argument as if it were compelling to those who don't share the starting assumption.
Map the argument and trace it back to its starting point
Ask: If I follow the chain of 'Why?' questions, does it eventually return to the original conclusion?
Take the argument 'The Bible is reliable because it is inspired, and it is inspired because it is reliable.' Ask 'Why is it inspired?' and 'Why is it reliable?' and see if the answers circle back. Drawing the argument as a diagram — with arrows showing what supports what — makes the circularity visible.
Identify what evidence could break the circle
Ask: What external, independent evidence exists for the conclusion that does not already assume the conclusion?
For biblical authority, the independent evidences include: (1) manuscript tradition and textual stability; (2) historical corroboration where biblical events can be checked against archaeology and ancient sources; (3) the coherence of the canon's theology across diverse authors and centuries; (4) the early attestation of the documents by contemporaries; (5) the transformative social and personal effects across cultures. Each of these can be evaluated without assuming the conclusion.
Distinguish foundational circularity from argumentative circularity
Ask: Is the circularity I'm encountering at the foundational level (unavoidable for any worldview) or at the level of specific claims that should be supported by evidence?
The presuppositionalist insight is that some level of foundational commitment is unavoidable. But specific claims — 'the Exodus occurred in the 15th century BCE,' 'Paul wrote Hebrews,' 'the Septuagint's version of Jeremiah is earlier than the Masoretic text' — are not foundational commitments. They are specific historical and textual claims that must be evaluated by evidence, not by the authority of Scripture.
Ask whether the argument is compelling to those who don't share the starting assumption
Ask: Would someone who doesn't already believe the conclusion find this argument persuasive? If not, is it actually an argument, or a restatement of the conclusion?
Apologetics — the reasoned defense of faith — requires arguments that can engage those outside the faith. An argument that only works for those who already believe it is not an argument; it is a formulation of belief. Recognizing this does not weaken faith but clarifies what kind of work the argument can and cannot do.
Reformulate the argument with genuine evidential support
Ask: How can I support this conclusion using evidence that does not assume the conclusion?
The Toulmin Model is helpful here: distinguish the claim from the data (evidence for the claim), the warrant (the principle connecting data to claim), and the backing (support for the warrant). Each element should be independently supportable. Isaiah 1:18 models the standard: 'Come, let us reason together.' Genuine reasoning invites examination from the outside, not just confirmation from the inside.