Circular Reasoning

Also Known As: Begging the Question Petitio Principii Circular Logic

Informal Fallacy 📰 Media Bias ID: circular_reasoning

Definition

Circular reasoning occurs when the conclusion of an argument is assumed, explicitly or implicitly, in one of its premises. Rather than providing independent support, the argument loops back on itself, making it logically valid but epistemically empty. It can be difficult to detect when the circle is large or the conclusion is rephrased in the premises.

Examples

"The Bible is the word of God because it says so in the Bible, and the Bible is trustworthy because it's the word of God."

This investment strategy is the most profitable because it generates the highest returns, and we know it generates the highest returns because it's the most profitable strategy.

Senator Hayes is the most qualified candidate because she has the best credentials, and we know she has the best credentials because she is clearly the most qualified candidate.

Formal Logic Pattern

FOL Pattern

The First-Order Logic formula representing this reasoning pattern's logical structure.

FOL (First-Order Logic) uses quantifiers (∀ = for all, ∃ = there exists), connectives (∧ = and, ∨ = or, ⇒ = implies, ¬ = not), and predicates to capture the essential form of a reasoning pattern. For example, the Ad Hominem fallacy: Person(x) ∧ HasFlaw(x) ⇒ Invalid(Claim(x)). These patterns allow automated verification of logical validity.

View in glossary →

A ⇒ B ⇒ A (circular)

Formal Verification: Not formally decidable

Verification Steps

Verification Steps

Binary yes/no questions that an AI must answer to detect a reasoning pattern in a text.

Each of the 452 aspects has verification steps — simple yes/no questions designed to systematically detect whether a pattern appears in a text. For ad hominem: "Does the argument attack a person rather than their claim?" For false dichotomy: "Are only two options presented when more exist?" This ensures consistent, reproducible analysis.

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Binary (yes/no) questions an LLM must answer to identify this aspect:

1

Does the conclusion appear (possibly rephrased) among the premises?
Type: binary
2

Is there a circular chain where A supports B and B supports A?
Type: binary
3

Can any premise be verified independently of the conclusion?
Type: binary

Description

Why It Works

When the premise and conclusion use different wording, the circularity is hidden. People also tend to accept arguments that confirm beliefs they already hold, making them less likely to notice the loop.

How to Counter

Ask whether any premise can be established independently of the conclusion. If removing the conclusion makes the premises unsupported, the argument is circular.

Also Known As

Begging the Question Petitio Principii Circular Logic

Real-World Context

Common in religious apologetics, political ideology ('our system is the best because our values are correct, and our values are correct because our system produces them'), and self-referencing corporate mission statements.