◆ The Codex · 7 of 16
Circular reasoning
Using the conclusion as its own premise.
Also known as
Begging the questionPetitio principiiCircular argument
The shape of the move
X is true because Y. Y is true because X — or simply: X is true because X.
What is the circular reasoning fallacy?
A circular argument assumes what it's trying to prove. The "reason" offered is just the conclusion in different words, so it adds no support at all.
It's often disguised by rephrasing or by spreading the circle across several steps, so the loop isn't obvious at first.
Examples
Everyday
“He's trustworthy because he's an honest man.”
Why it fails: Trustworthy and honest mean the same thing here.
Online
“This news site is reliable because it says it only publishes the truth.”
Why it fails: The site's own claim is used to prove the site's claims.
In a debate
“Reading is valuable because books are worth reading.”
Why it fails: "Valuable" and "worth reading" are the same claim.
Why it feels convincing
Restated claims sound like confirmation. Repetition builds familiarity, and familiarity feels like truth.
Spot it: Strip the wording: the reason IS the claim, restated.
In the arena
If you’re about to commit it
- Ask: would someone who disagrees accept my reason?
- Make sure your evidence is independent of your conclusion.
- Replace definitions with data or examples.
Instead of
“Exercise is good for you because it's healthy.”
Try
“Exercise lowers resting blood pressure by about 5–8 mmHg on average, reducing stroke risk.”
If your opponent commits it
- Restate the argument plainly to reveal the loop.
- Ask for a reason that doesn't assume the conclusion.
Say this
“That reason is just the claim restated. What's the evidence that doesn't already assume it?”
When it’s not a fallacy
Definitions and tautologies ("a bachelor is unmarried") are circular by nature but aren't fallacies — they aren't trying to prove anything new.
How the Oracle scores it
In an Arguen match, every argument is scored out of 80 across Clarity, Evidence, Logic and Rebuttal. If the Oracle detects a circular reasoning, it subtracts a penalty and puts the fallacy on your scorecard with the exact quote and a one-sentence explanation — so you see precisely where the chain snapped.
Frequently asked questions
Is circular reasoning the same as begging the question?
Yes, in logic. In everyday speech "begs the question" is often used to mean "raises the question", but the original meaning is circular reasoning.
Can a circular argument be true?
The conclusion can happen to be true, but the argument gives no reason to believe it.