Ignoratio elenchi

Ignoratio elenchi (also known as irrelevant conclusion or irrelevant thesis) is the informal fallacy of presenting an argument that may in itself be valid, but doesn't address the issue in question. "Ignoratio elenchi" can be roughly translated by ignorance of refutation, that is, ignorance of what a refutation is; "elenchi" is from the Greek έλεγχος, meaning an argument of disproof or refutation.^[1] (Some sources give by ignorance of the issues or even by ignoring the issues as a translation of ignoratio elenchi. This is linguistically impossible as a translation of the Latin phrase.)

Aristotle believed that an ignoratio elenchi is a mistake made by a questioner while attempting to refute a respondent's argument. He called it an ignorance of what makes for a refutation. For Aristotle, then, ignoratio elenchi amounts to ignorance of logic. In fact, Aristotle goes so far as to say that all logical fallacies can be reduced to what he calls ignoratio elenchi.

Modern use limits this term much more narrowly to the kind of mistake described in the first paragraph above.

Red herring

Similar to ignoratio elenchi, a red herring is an argument, given in reply, that does not address the original issue. Critically, a red herring is a deliberate attempt to change the subject or divert the argument.

Tu quoque

Tu quoque, Latin for "And you too!", is another deliberate diversion from the original issue. It asserts that the advice or argument must be false simply because the person presenting the advice doesn't follow it himself. Tu quoque is frequently seen in conjunction with an ad hominem argument, when the assertion implies wrongdoing on the part of the presenter.

Examples

• Baseball player Mark McGwire just retired. He's such a nice guy, and he gives a lot of money to all sorts of charities. Clearly, he will end up in the Hall of Fame.

The conclusion is ignoratio elenchi, since friendliness and charity are not the main qualifications for induction into the Hall of Fame.

• I should not pay a fine for reckless driving. There are actual dangerous criminals on the street, and the police should be chasing them instead of harassing a decent tax-paying citizen like me.

The existence of worse criminals is a secondary issue which has no bearing on whether the driver deserves a fine for recklessness. If the speaker were deliberately attempting to divert the issue, this would be an example of a red herring. While the argument about how the police should spend their time may have merit, the question of whom the police should prioritize pursuing and the question of what should be done with those the police have caught are separate questions.

• The premier's tax policies may be popular, but I suspect he had an affair and is paying the woman to keep quiet. The media should investigate that!

A red herring, the unrelated alleged affair, attempts to change the subject away from the popular policies. However, if the original discussion were of the premier's public integrity (encompassing both popularity and conduct), this argument could be perfectly valid.

• Thomas Jefferson argued that slavery was wrong and should be abolished, but since Jefferson himself owned slaves, it clearly was not wrong.

An example of tu quoque: slavery was either right or wrong, regardless of Jefferson's actions. The validity or truth-value of Jefferson's argument is not affected by his participation in slavery (though it does introduce an element of hypocrisy).

References

See also

• Enthymeme
• Chewbacca defense

External links

• About.com: Fallacies of relevance
• Nizkor Project: Red Herring
• Fallacy Files: Red Herring
• The Art of Controversy: Diversion (bilingual with the original German) by Arthur Schopenhauer
• Red herring in political speech

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