Sound Argument

A sound argument is valid and has all true premises. Soundness is the full package: the logic holds and the facts check out. On the LSAT you usually test validity, not soundness, because you take the premises as given.

Example

"All mammals breathe; whales are mammals; so whales breathe" is sound.

See also

• Valid Argument
• Deductive Reasoning
• Premise

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Last updated October 12, 2026