Refutation is the act of proving an argument to be in error logically, or to be false. In pointing to what is wrong with an argument, the writer or speaker does not want to oversimplify the opponent's argument. Here are some ways to refute arguments:
1. Identify a flaw in the reasoning. There are several logical fallacies among which are these:
- Appeal to authority - This is the mentioning of a respected source; however this source may not actually be an authority
- Bandwagon - This is an appeal to people's wish to be among those who are popular and to "join in on conventional wisdom."
- Hasty generalizations - There is no real evidence. e.g. "Wealthy people are snobs."
- Missing the point - The premises of an argument do not support a particular conclusion. (illogical)
- Weak analogy - If two things that are being compared are compared are not really alike, then the reasoning of the analogy is not sound.
- Ad hominem - This is an attack on the person rather than upon the logic of the statement.
- Appeal to ignorance - The argument is made that there is no conclusive evidence, so the reader/listener should accept the conclusion.
- Red herring - This is a digression to a side issue that detract from what is really at stake.
- False dichotmy - This is a leading of people to a belief that an "either-or" condition exists and there are only two choices.
- Begging the question - The listener/reader is asked to accept the conclusion without any real evidence.
- Equivocation - This is a vacillation between two or more different meanings of a single word or phrase that is essential to the argument, thus clouding its meaning
2. Find information the opposing argument has not considered, something that will deflate the argument. For instance, is there is an argument for ending a program for lack of funding, and you know where funding can be found, this would be a counter-argument.
3. Look for a way to make your argument stronger than the opposing one. For instance, in the Colonial days of America, many argued that they were at peace and the British soldiers in their doorways had not harmed them, so there was no need to fight for liberty. Thomas Paine pointed out that once the British learned that if the Colonists offered no resistance, the soldiers would soon impose more restrictions until the Colonists became totally servile (he offered examples as proof of this). Therefore, it was important to resist then and not delay.
Refutation is both an argumentative strategy and one of the six parts of the classical oration.
The classical oration, as described in Cicero's de Inventione and the pseudo-Ciceronian Rhetorica ad Herennium, consists of six parts, introduction, narration, division, proof, refutation, conclusion. In the division (or partition), you discuss what you will choose to argue and which parts of your opponent's argument you will refute. In the refutation, you refute not only actual counter-arguments to your claim but any possible counter-arguments you might anticipate.
The two main ways of disproving an argument are showing that it is formally invalid or materially incorrect.
Formal invalidity refers to logical errors, or conclusions not following from premisses, irrespective of whether the statements correspond to an actual state of affairs. For example, I might say "Dr. Smith's hair is blonde and therefore he isn't a lawyer." Even if Dr. Smith's hair is blonde, and Dr. Smith is a doctor, not a lawyer, the complete statement, despite being factually correct, is formally invalid because the colour of Dr. Smith's hair has no logical connection with his profession.
Material incorrectness refers to getting facts wrong. Examine the claim: "All dogs are purple. Spot is a dog. Therefore Spot is purple." This is logically valid. The conclusion follows from the premisses. Since, however, all dogs are not purple, it is materially incorrect.
There are other tactics for casting doubt on an argument which are not strictly refutation. Many can verge on unethical. For example, political attack ads often try to undermine opposing candidates' positions by attacking their personal character and trying to make them seem unpatriotic or out of touch with voters. Another strategy is the reductio ad absurdum, in which you show that an opponent's position would lead to absurd or undesireable consequences.