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

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

Scientists found indirect proof of gravitational waves in the 1970s by studying the orbits of two colliding stars, and the work was honored as part of the 1993 Nobel Prize in physics.

From Washington Times

Indirect proof of gravitational waves’ existence has been found over the years, most notably by measuring radio emissions from pairs of dead stars called pulsars that are orbiting one another, and deducing from this how the distance between them is shrinking as they broadcast gravitational waves into the cosmos.

From Economist