What does counterexample mean in LR

[hnadgauda]

What does counterexample mean? It is used in LR answer choices often.

[ohthatpatrick]

A counterexample is a specific idea that goes against a general principle.

General principle: It is wrong to lie
Counterexample: It was CORRECT when Susan lied to Bob in order to preserve the surprise party everyone planned for Bob.

Almost all of the time, a counterexample is going against an “If, then” rule. It always takes the form of an example in which something IS the left side (the sufficient idea) but IS NOT the right side idea (the necessary idea).

“All girls like Justin Bieber”.

Which is a counterexample:
Bob, who is a boy, likes Bieber.
Jane, who is a girl, doesn’t like Justin Bieber.
or both?

Only the Jane fact is a counterexample.

The original rule is that “Girl --> like Biebs”, so a counterexample has to take the form of someone who IS a girl but who IS NOT a fan of Bieber.

Counterexamples are often named with specific proper nouns (like “Jane”), but they can also just be said generically: “Some girls don’t like Justin Bieber”.