Literal Meaning
To reduce something to absurdity
Origin
Latin
Explanation
It is a strategy of diminishing an argument or theory to absurdity, bringing the assumptions or implications of the case beyond their logical limits and demonstrating how ludicrous the effects will be, thus disproving or discrediting the argument. It involves characterizing an opposing argument in such a way that it seems to be ridiculous, or the consequences of the position seem ridiculous. It can be ridiculous in the sense that the argument seems silly, or ridiculous in the sense that no reasonable person would take such a position. In common speech, the term reductio ad absurdum refers to anything pushed to absurd extremes.
Illustration
A is going into surgery tomorrow so he requests people to pray for him. A thinks that if enough people pray for him, God will protect him from harm and see to it that he has a successful surgery and speedy recovery.
We first assume the premise is true: if “enough” people prayed to God for the patient’s successful surgery and speedy recovery, then God would make it so. From this, we can deduce that God responds to popular opinion. However, if God simply granted prayers based on popularity contests, that would be both unjust and absurd. Since God cannot be unjust, then he cannot both respond to the popularity and not respond to popularity, the claim is absurd, and thus false.
Case Laws
In Moti Ram & Ors vs. the State of M.P., the Supreme Court of India observed that “It is not the court’s status but the applicant guilt status that is germane. That a guilty man may claim judicial liberation pro tempore without sureties while an undertrial cannot, is a reduction ad absurdum.”
In Raj Kumar Singh @ Raju @ Batya vs. the State Of Rajasthan, the court observed that “the force and effect of circumstantial evidence depend upon its incompatibility with, and incapability of, explanation or solution upon any other supposition than that of the truth of the fact which it is adduced to prove; the mode of argument resembling the method of the demonstration by the reductio ad absurdum.”