Presumption

Begging the Question

Also known as: circular reasoning, petitio principii

Using your conclusion as one of your premises — the argument assumes the very thing it's supposed to prove.

Examples

A friend recommends a book at a used bookstore.

Ravi: “This book is completely accurate — you can trust every page.” Sana: “How do you know that?” Ravi: “Because right in the introduction, it says everything in the book is true.”

The only support for “the book is accurate” is the book’s own claim that it’s accurate. The conclusion is doing double duty as its own evidence — nothing outside the book was actually checked.

The same loop shows up in online product debates:

Comment: “This app’s premium tier is worth the $12 a month.” Reply: “Why do you think that?” Comment: “Because it’s the premium version — premium versions are always worth the extra cost.”

“Premium is worth it because it’s premium” offers no independent reason; it just restates the price tier as if that settled the value question.

Why the reasoning fails

Begging the question happens when a premise offered as support for a conclusion is really just the conclusion restated in different words — or, in a short loop, is justified by the conclusion itself. A sound argument needs premises that are independently true and lend actual support; here, the premise only holds up if the conclusion is already accepted, so the “argument” goes in a circle instead of building a case. No new information ever enters the argument — it just walks back to where it started.

Note that everyday speech often uses “begs the question” to mean “raises the question,” as in “that begs the question of what happens next.” That’s a different, informal usage, not this fallacy.

How to respond

  • Ask for independent support: “Is there evidence for that outside of the claim itself?”
  • Trace the loop out loud: “So the reason it’s true is that it says it’s true? That’s circular.”
  • Ask what would count as evidence against it. If nothing could, the claim may be built to be unfalsifiable rather than proven.
  • Keep it low-key for short, harmless loops. Casual circular remarks (“it’s good because it’s good”) usually aren’t worth a formal callout unless a real decision hinges on them.