If a deductive argument is valid but has at least one false premise, the argument is?

• A. Invalid
• B. Sound
• C. Cogent
• D. Valid But Not Sound

Answer: (D)

This question hinges on validity versus soundness in deductive reasoning. A valid argument is one where the conclusion would have to be true if all the premises were true; it cares about the form, not the actual truth of the premises. Soundness adds the requirement that every premise actually is true. So, an argument can be valid even if some premise is false, but then it’s not sound.

Since the argument follows a valid deductive form, it’s correctly labeled as valid. However, because at least one premise is false, it cannot be sound. Cogent is a term used for strong inductive arguments with true premises, so it doesn’t apply here. Invalid would be the label if the logical form didn’t guarantee the conclusion from the premises, which isn’t the case. The best description is valid but not sound.