indirect proof

American  

noun

1. an argument for a proposition that shows its negation to be incompatible with a previously accepted or established premise.

---

indirect proof British  

noun

1. logic maths proof of a conclusion by showing its negation to be self-contradictory; reductio ad absurdum Compare direct

---

Example Sentences

Italy rejected that explanation, even after the Egyptian police produced Mr. Regeni’s passport, which they said had been found in an apartment of one of the dead men, — indirect proof, Italian officials said, that the true culprits were with Egyptian security.

From New York Times

I was about to begin going over the steps of indirect proof when I heard Danny say, “You’re always sleeping! What a sleepyhead you are!” and I opened my eyes.

From Literature

“I was just going into the indirect proof. Do you want to hear it?”

From Literature

It’s uncanny but still indirect proof.

From The Verge

We cannot see these ancient behemoths directly with current technology, but we can, say astronomers, capture an indirect proof of their activity.

From BBC