Practice question · Select all that apply
Which translations are correct?
Hints
- Three are standard translations; two of the options concern the same phrase and disagree.
- "Only if" marks a necessary condition, so it introduces the consequent.
Show the answer
- A. "P only if Q" becomes if P then Q
- B. "P unless Q" becomes P or Q
- C. "Neither P nor Q" becomes not-P and not-Q
Why
"Only if" marks a necessary condition: "you may vote only if registered" means voting registered. Reversing it would say registration guarantees voting, which is a quite different and much stronger claim.
Practise The Language of Propositional Logic
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More questions on The Language of Propositional Logic
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- Sort each sentence by whether the main connective is a conjunction, a disjunction or a conditional.
- Complete the account of the material conditional.