Fallacies of irrelevance

Ignoratio elenchi, also known as irrelevant conclusion, is the informal fallacy of presenting an argument that may or may not be logically valid, but fails nonetheless to address the issue in question. More colloquially, it is also known as missing the point.

Ignoratio elenchi falls into the broad class of relevance fallacies. It is one of the fallacies identified by Aristotle in his Organon. In a broader sense he asserted that all fallacies are a form of ignoratio elenchi.

Ignoratio Elenchi, according to Aristotle, is a fallacy which arises from "ignorance of the nature of refutation". In order to refute an assertion, Aristotle says we must prove its contradictory; the proof, consequently, of a proposition which stood in any other relation than that to the original, would be an ignoratio elenchi. Since Aristotle, the scope of the fallacy has been extended to include all cases of proving the wrong point… "I am required to prove a certain conclusion; I prove, not that, but one which is likely to be mistaken for it; in that lies the fallacy… For instance, instead of proving that ‘this person has committed an atrocious fraud’, you prove that ‘this fraud he is accused of is atrocious;’" … The nature of the fallacy, then, consists in substituting for a certain issue another which is more or less closely related to it, and arguing the substituted issue. The fallacy does not take into account whether the arguments do or do not really support the substituted issue, it only calls attention to the fact that they do not constitute a proof of the original one… It is a particularly prevalent and subtle fallacy and it assumes a great variety of forms. But whenever it occurs and whatever form it takes, it is brought about by an assumption that leads the person guilty of it to substitute for a definite subject of inquiry another which is in close relation with it.

The phrase ignoratio elenchi is from Latin, meaning 'an ignoring of a refutation'. Here elenchi is the genitive singular of the Latin noun , which is from Ancient Greek ἔλεγχος (elenchos), meaning 'an argument of disproof or refutation'. The translation in English of the Latin expression has varied somewhat. Hamblin proposed "misconception of refutation" or "ignorance of refutation" as a literal translation, John Arthur Oesterle preferred "ignoring the issue", and Irving Copi, Christopher Tindale and others used "irrelevant conclusion".

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