contrapositive
- noun
- /ˌkɒntrəˈpɒzɪtɪv/
- Specialized
- When analyzing logical arguments, it is essential to remember that the contrapositive of a true statement is always true.
Examples
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The professor explained that the contrapositive serves as an important tool in proofs, as it can help establish the validity of a claim.
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Then the last one is going to be the contrapositive, which is going to be the if, if inverse or if not Q then not P.
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In mathematics, the contrapositive of the statement 'If it rains, then the ground is wet' is 'If the ground is not wet, then it does not rain.'
Synonyms
To form a new if-then statement by switching the two parts and saying each is not true
Surface Forms
Etymology
A contrapositive comes from contra- 'against' and positive 'affirming', so the name suggests an 'against the affirmative' statement. A contrapositive is the statement you get when you swap the 'if' and 'then' parts and make them negative, and this explains why we use that word for this logical form.