...proving, or disproving something by a single counter example? For instance, if someone said "all birds can fly", I could disprove that by saying "there exist a bird called the penguin which cannot fly".

I think it may be a latin word.

And no, I'm not looking for the word "counter example".

 

How about a redargutory result?

John

 

Proof by contradiction.

 

(also known as reductio ad absurdum, Latin for "by reduction toward the absurd")

 

How about "refutation"?

 

proof by contradiction= "reducto ad absodum"

 

proof by contradiction= "reducto ad absodum"

That is not a valid Latin phrase according to http://www.nd.edu/~archives/latin.htm

"absodum" is not in the Notre Dame Latin dictionary.

John

 

jut,

What's the word for...

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...proving, or disproving something by a single counter example? For instance, if someone said "all birds can fly", I could disprove that by saying "there exist a bird called the penguin which cannot fly".

I think it may be a latin word.

And no, I'm not looking for the word "counter example".

Why don't you ask thingmaker3. He is big on Latinisms.

Ratch

 

That is not a valid Latin phrase according to http://www.nd.edu/~archives/latin.htm

"absodum" is not in the Notre Dame Latin dictionary.

John

it's a typo. he meant reducto ad absurdum, which is the phrase.

 

it's a typo. he meant reducto ad absurdum, which is the phrase.

I suspect you mean, "reductio ad absurdum," which does not meet the OP requirement for a single, contradictory example.

In formal logic, reductio ad absurdum (Latin: "reduction to the absurd") is an argument to refute a proposition (or set of propositions), by showing that it leads to a logically absurd consequence.[1] That is, the proposition is shown by proper inspection to be simply untenable within the rules of logic, because it necessarily leads to a self-contradictory consequence.

John