Adult tool

Valid vs Sound Checker

Valid means the conclusion follows. Sound means valid and the premises are true.

Definition

An argument is valid when the conclusion must follow if the premises are true. It is sound when it is valid and the premises are actually true. Validity is about structure; soundness is about structure plus truth.

Many persuasive-sounding claims are invalid (the conclusion does not follow) or valid but unsound (a false premise). Inductive arguments are judged strong or weak rather than valid or sound.

From the book

Chapter 3–5 in Think Straight, Argue Better — practice here, then return to the chapter examples.

Practice

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Question 1 of 8

All birds can fly. Penguins are birds. Therefore, penguins can fly.
Is this argument valid? Is it sound?