Tu quoque or the appeal to hypocrisy, is a kind of logical fallacy

Fallacy

In logic and rhetoric, a fallacy is usually an incorrect argumentation in reasoning resulting in a misconception or presumption. By accident or design, fallacies may exploit emotional triggers in the listener or interlocutor , or take advantage of social relationships between people...

. It is a Latin

Latin

Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...

 term for "you, too" or "you, also". A tu quoque argument attempts to discredit the opponent's position by asserting his failure to act consistently in accordance with that position; it attempts to show that a criticism or objection applies equally to the person making it. This dismisses someone's point of view on an issue on the argument that the person is inconsistent in that very thing. It is considered an ad hominem

Ad hominem

An ad hominem , short for argumentum ad hominem, is an attempt to negate the truth of a claim by pointing out a negative characteristic or belief of the person supporting it...

argument, since it focuses on the party itself, rather than its positions.

Illegitimate use

In many cases tu quoque arguments are used in a logically fallacious

Fallacy

In logic and rhetoric, a fallacy is usually an incorrect argumentation in reasoning resulting in a misconception or presumption. By accident or design, fallacies may exploit emotional triggers in the listener or interlocutor , or take advantage of social relationships between people...

 way, to draw a conclusion which is not supported by the premises of the argument.

You-too version

This form of the argument, familiar from everyday disagreements, is as follows:

A makes criticism P.

A is also guilty of P.

Therefore, P is dismissed.

Examples:

• "He cannot accuse me of libel because he was just successfully sued for libel."

• Person 1: It should be illegal to make clothing out of animals.
• Person 2: But, you are wearing a leather jacket.

• Person 1: People shouldn't drink. It's a very damaging habit.
• Person 2: But you're drunk.

Even judged by the one target the [Conservative Party] chancellor [Osborne] had set himself - getting the deficit down - he was "failing", said Mr Balls [Labour Party].
"Compared to his plans of a year ago he is now planning to borrowing a staggering £158bn more."
...
But Mr Osborne derided his opposite number.
"As far as I can tell the shadow chancellor complains that we are borrowing too much and then proposes that we borrow even more!" he said.
"There is not a single credible political party in the entirety of Europe that is proposing more spending, apart from the Labour Party." (Guardian, 29/11/11).

Inconsistency version

This form of the argument is as follows:

A makes claim P.

A has also made past claims which are inconsistent with P.

Therefore, P is false.

This is a logical fallacy because the conclusion that P is false does not follow from the premises; even if A has made past claims which are inconsistent with P, it does not prove that P is false.

Examples:

"You say aircraft

Fixed-wing aircraft

A fixed-wing aircraft is an aircraft capable of flight using wings that generate lift due to the vehicle's forward airspeed. Fixed-wing aircraft are distinct from rotary-wing aircraft in which wings rotate about a fixed mast and ornithopters in which lift is generated by flapping wings.A powered...

 are able to fly because of the laws of physics

Physics

Physics is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic...

, but this is false because twenty years ago you also said aircraft fly because of magic

Magic (paranormal)

Magic is the claimed art of manipulating aspects of reality either by supernatural means or through knowledge of occult laws unknown to science. It is in contrast to science, in that science does not accept anything not subject to either direct or indirect observation, and subject to logical...

."

• Senator Smith: It is important that we all vote for this legislation.
• Senator Jones: You just said last week that voting for it was a bad idea.

Legitimate use

The legitimate form of the argument is as follows:

A makes criticism P.

A is also guilty of P.

Therefore, A is dismissed (from his/her role as a model of the principle that motivates criticism P).

The difference from the illegitimate form is that the latter would try to dismiss P along with A. It is illegitimate to conflate the logically separate questions of whether P is a valid criticism and whether A is a good role model.

Examples of legitimate use:

• In disqualifying a self-appointed judge. "He can indeed accuse me of libel even though he was just successfully sued for libel, but perhaps he shouldn't."

Legal aspects

In common law

Common law

Common law is law developed by judges through decisions of courts and similar tribunals rather than through legislative statutes or executive branch action...

, a legal maxim exists stating a person cannot approach the courts of equity with unclean hands

Unclean hands

Unclean hands, sometimes called the clean hands doctrine or the dirty hands doctrine, is an equitable defense in which the defendant argues that the plaintiff is not entitled to obtain an equitable remedy on account of the fact that the plaintiff is acting unethically or has acted in bad faith with...

. If there is a nexus between the applicant's wrongful act and the rights he wishes to enforce, the court may not grant the applicant's request. To illustrate, if a landlord breaches a term in a tenancy agreement and then issues an eviction notice to the tenant for the tenant's breach of a term in the tenancy agreement, the law might permit the tenant to stay because of the landlord's own breach of the tenancy agreement.

This argument has been unsuccessfully used before the International Criminal Tribunal for the former Yugoslavia

International Criminal Tribunal for the former Yugoslavia

The International Tribunal for the Prosecution of Persons Responsible for Serious Violations of International Humanitarian Law Committed in the Territory of the Former Yugoslavia since 1991, more commonly referred to as the International Criminal Tribunal for the former Yugoslavia or ICTY, is a...

 in several cases when the accused tried to justify their crimes by insisting that the opposing side had also committed such crimes. However, the argument tu quoque, from the basis of international humanitarian law is completely irrelevant, as the ICTY has stated in these cases.

Historically, however, at the Nuremberg trial of Karl Dönitz

Karl Dönitz

Karl Dönitz was a German naval commander during World War II. He started his career in the German Navy during World War I. In 1918, while he was in command of , the submarine was sunk by British forces and Dönitz was taken prisoner...

, tu quoque was accepted not as a defense to the crime itself, or to the prosecution proceedings, but as a defense only to punishment. At the Dachau trials, Otto Skorzeny

Otto Skorzeny

Otto Skorzeny was an SS-Obersturmbannführer in the German Waffen-SS during World War II. After fighting on the Eastern Front, he was chosen as the field commander to carry out the rescue mission that freed the deposed Italian dictator Benito Mussolini from captivity...

 and officers of Panzer Brigade 150

Panzer Brigade 150

Panzer Brigade 150 or SS Panzer Brigade 150 was a formation of the German Army during World War II that was formed to take part in the Ardennes offensive, it was unusual in that it was formed from all parts of the German Armed Forces, the 2.500 men in the brigade were formed from; 1.000 from the...

 successfully used tu quoque evidence to be acquitted of violating the laws of war by using American uniforms to infiltrate Allied lines in the false flag

False flag

False flag operations are covert operations designed to deceive the public in such a way that the operations appear as though they are being carried out by other entities. The name is derived from the military concept of flying false colors; that is flying the flag of a country other than one's own...

 Operation Greif

Operation Greif

Operation Greif was a special false flag operation commanded by Waffen-SS commando Otto Skorzeny during the Battle of the Bulge. The operation was the brainchild of Adolf Hitler, and its purpose was to capture one or more of the bridges over the Meuse river before they could be destroyed...

 in the Battle of the Bulge

Battle of the Bulge

The Battle of the Bulge was a major German offensive , launched toward the end of World War II through the densely forested Ardennes mountain region of Wallonia in Belgium, hence its French name , and France and...

. Evidence was introduced that the Allies themselves had on at least one occasion worn German uniforms, demonstrating that the prosecution was not clean with regards to this particular crime.

See also

• Pot calling the kettle black
  Pot calling the kettle black
  The phrase "The pot calling the kettle black" is an idiom used to accuse a person of being guilty of the very thing of which they accuse another. This may or may not be hypocritical or a contradiction.-Alternative interpretation:...
  
  
• And you are lynching Negroes
  And you are lynching Negroes
  "And you are lynching Negroes" is an anecdotal counter-argument phrase often used by the Soviet propaganda in response to allegations that Soviet Union had violated human rights...
  
  
• Unclean hands
  Unclean hands
  Unclean hands, sometimes called the clean hands doctrine or the dirty hands doctrine, is an equitable defense in which the defendant argues that the plaintiff is not entitled to obtain an equitable remedy on account of the fact that the plaintiff is acting unethically or has acted in bad faith with...