Logic deals with the validity of arguments, and can be deductive, from the general to the particular case, or inductive, from the particular to the general. According to Aristotle, who can be considered the founder of this discipline, formal logic deals with the validity, with the correctness of the arguments, not with their truth. If all men play football and I am a man, I play football: it is a correct reasoning from the logical-formal point of view, but not true insofar as I do not play football: the truth of a conclusion is linked not only to logic, but also to the truth of the premises. If the premises are true and the reasoning is logical, the conclusions are also true.
Deductive logic, especially syllogistic logic, is extremely rigorous, but not very suitable for common discussions, where we use a more approximate procedure. This means that we often fall into fallacies, that is, arguments that seem logical – this is the reason for their effectiveness – but contain serious errors, and in this Psychology-Online article we will discover 25 types of fallacies with examples.
Fallacy of mistake
It occurs when the same expression is used with two or more meaningsone of them in the premise and the other in the conclusion.
- For example, in the phrase “logic is better than nothing, nothing is better than health,” the conclusion depends on the meaning we want to give to the word “nothing.”
Fallacy of amphibology or grammatical ambiguity
It is a speech or an expression that contains a syntactic ambiguity and, therefore, it can be interpreted in different ways depending on the way you read it. In general, we speak of amphibolia, that is, a structural ambiguity that does not reside in one or several words, but in the way in which the words are linked to each other. We often find ourselves dealing with amphibologous when there are several quantifiers present in the same sentence.
- For example, the phrase “all the boys love a girl” can mean that “there is a girl that all the boys love” or “all the boys love some girl.”
Fallacy of vagueness
We are referring to that form of indetermination that does not manifest itself in the presence of multiple meanings, but in the absence of rigorous criteria for the correct use of a word.
- For example, in the sentence “refined palates prefer red wine, I have a refined palate, so I should drink the wine”, what is a refined palate and who has it? And who likes red wine?
Doublethink Fallacy
When each statement cancels out the other, everything and nothing is said. We will better understand this type of fallacy with an example:
- Example of the doublethink fallacy: “individuals are good and bad.”
accent fallacy
This type of fallacy tries to draw conclusions that are not due to the change of accent from one word to another.
For example, in the phrase “the queen can only be praised”, there can be two different readings:
- We are not free to criticize the queen when the emphasis is placed on the word queen.
- We are really praising the queen if the accent is placed on the praised word.
Fallacy of composition
The next of the types of fallacies is the fallacy of composition. It is the case in which overall quality is wrongly deduced of an object depending on the quality of its components.
- Example: the Barcelona team is the winner because it is made up of players who are active in the nation.
division fallacy
It is the inverse of the previous one, and occurs when the set has certain characteristics and The same characteristics are attributed to the parts that compose it.
- For example, “Pau knows everything because he works at the university.”
Undue generalization
We fall into this type of fallacy when we take a conclusion about an entire class of objects from information about one or some of its components.
- For example: a man stole an apple. Therefore, all men are thieves. In doing so, an “improper generalization” occurred.
Statistical generalization
It is pseudoinductive reasoning that is based on a numerically insufficient samplingwhile it aims to have a general conclusion.
- Example: “Of a group of 500 Spanish teenagers, 80% surf the Internet for more than three hours a day. So 80% of Spanish teenagers surf the Internet more than three hours a day.”
Gambler’s Fallacy
In this type of fallacy, it is believed that the probability of occurrence of an event It depends on how long it’s been since it happened, although that’s not the case. It has the following form: “Event X has not occurred for a long time, so it will occur soon.”
- Therefore, an example could be “the number 82 has not been drawn in the lottery for a long time; therefore, the number 82 will be drawn soon.”
false cause
This fallacy occurs when something is made to appear because of an event that is not an event, or when arbitrarily attributed a cause to an event without having considered the alternatives.
- Example: “I should never have taken the exam on Friday. Every time I take it on Friday they fail me. In this case we have a false cause.”
Fallacy of suppressed evidence
In this case, the one who proposes a thesis remains silent about a hidden premise, and a circular reasoning, for which the thesis seems true. But if the information contained in the premise emerges, they will invalidate the conclusion.
- Example: “Many cats do well in the apartment. They are affectionate and love to be petted. So this cat will most likely make a good pet.”
The premises are true, relevant, and the inductive probability is high. But if the author were silent about the fact that the cat in question lived much of his time in an abandoned cat shelter, where he became suspicious and aggressive, it is clear that the argument would be flawed by the fallacy of suppressed evidence. .
pathetic fallacy
An expression coined by the British poet John Ruskin that consists of attribute emotion and behavior human to things that are found in nature, that is, that are not human. It is the basis of some divination methods.
- A physical example might be: “Air hates being compressed, so it counteracts the pressure placed on it.”
Petitio principii or simple circularity
That is, the assumption of the truth of what is intended to be demonstrated. The argument is called “circular”, since among the premises of an argument is the thesis that one wants to support. Let’s look at an example of this type of fallacy:
- God created the world, so God exists.
- God exists, so God created the world.
The argument contains a premise and a conclusion, but they are not consistent. It is obvious that the conclusion is already contained in the first premise.
Multiple (or complex) question fallacy
We talk about this type of fallacy when something is assumed in the question which has not yet been proven. Typically used as a verbal trap to fool fools.
- For example: “Did you stop robbing banks?”: in this case, the question represents an answer to a logically previous question.
Ignoratio elenchi or fallacy of wrong conclusion
It manifests itself when the premises support a different conclusion than that which appears in the formulation of the argument. For example example:
- The inflation rate is negative for the economy;
- Today the inflation rate (on an annual basis) is 7%, while last month inflation galloped at a rate of 10%;
- so the economy is improving.
In this case, what really follows from the premises is that the inflation rate is falling. This is very different from what was stated in the conclusion, that is, that the economy is doing well. The premises do not support the conclusion.
Non sequitur fallacy
This type of fallacy, also called a “red herring”, consists of illicitly assuming as a cause something that is not.
- For example: “The country is under the threat of terrorism. It is urgent to buy new, increasingly powerful weapons.” The argument is fallacious, since terrorism is not necessarily combated by acquiring new weapons (existing ones can also be effective).
puppet theme
To deny a thesis without addressing it directly, an apparently similar thesis is refuted constructed ad hoc, less plausible. During the dispute, the ad hoc thesis is refuted, and by logical consequence the thesis that was intended to be attacked also falls. But the argument used is a puppet: it is false, just as the thesis constructed ad hoc is a puppet-thesis.
fallacy of change
Cognitive distortion through which It is assumed that others can and should change, to respond to your wants and needs. The usual strategies for trying to bring about change in others include criticism and blaming. Known .
reward fallacy
This type of fallacy or cognitive distortion that consists of expectation that the other will show gratitude for a generous action.
control fallacy
Cognitive distortion related to the evaluation of the control that the individual thinks he or she has over events. This fallacy has two variants:
- Subjects with external locus of control (hypocontrol fallacy) develop the conviction of having little or no control about the environment.
- Subjects with extreme internal locus of control present the opposite problem.
Equity Fallacy
It is a type of cognitive distortion and consists of conviction that the evaluation systems themselves are intrinsically valid and, therefore, applicable to everyone and under all conditions. It is expressed in the conviction that everyone should have the same values.
Ad baculum fallacy
Imposing a thesis by threatening resort to force or exerting some form of pressure on the interlocutor. In some cases, the appeal is not intended to stir emotions, but rather uses the emotion aroused to support a certain conclusion.
Ad Misericordia Fallacy
We talk about this type of fallacy when we appeal to mercy or to compassion.
- Example: “Officer, don’t give me a ticket for going over the speed limit, my father would kick me out of the house and my girlfriend would leave me.”
Ad populum fallacy
Let’s look at the last type of fallacy on this list of types of fallacies. The ad populum fallacy occurs when arguing for or against a thesis appealing to popular sentiments or to shared opinions rather than reason.
This article is merely informative, at Psychology-Online we do not have the power to make a diagnosis or recommend a treatment. We invite you to go to a psychologist to treat your particular case.
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Bibliography
- Gutiérrez, GA (2000). Introduction to logic. Pearson Education.
- Lekuona Ruiz de Luzuriaga, K. (2013). Formal and informal logic: fallacies and false arguments (didactic unit).
- Rizzotto, L. (2021). Le fallacie: an introduzione ai ù comuni inganni dell’argomentazione. Retrieved from: https://www.psyjob.it/le-fallacie-una-introduzione-ai-piu-comuni-inganni-dellargomentazione.htm