The 10 types of logical and argumentative errors

Philosophy and psychology are related to each other in many ways, not least because they somehow approach the world of thought and ideas.

One of these points of union between the two disciplines concerns the logical and argumentative errors, concepts used to denote the validity (or lack thereof) of conclusions drawn from a dialogue or debate. Let’s see in more detail what they consist of and what are the main types of errors.

What are errors?

An error is a reasoning that while it may seem like a valid argument, it is not.

This is therefore flawed reasoning and inferences presented as a product thereof cannot be accepted. Regardless of whether the conclusion drawn from an error is true or not (it could be by pure chance), the process by which it was reached is flawed, because it violates “at least one logical rule”.

Errors and psychology

In the history of psychology, there has almost always been a tendency to overestimate our ability to think rationally, to be subject to logical rules, and to be consistent in the way we act and discuss.

With the exception of certain psychological currents such as the psychoanalysis founded by Sigmund Freud, it has been taken for granted that the adult human being and his work according to a series of motives and reasonings which can be easily expressed verbatim and that they generally fall within the framework of rationality. Cases in which a person behaved irrationally have been interpreted either as a sign of weakness or as an example where the person does not know how to identify the real reasons behind his actions.

It is during the last decades that the idea that irrational behavior is central to our lives began to be acceptedThis rationality is the exception, not the other way around. However, there is one reality that already gave us a clue as to how far we move with little or no emotions and rational impulses. The point is, we have had to develop some kind of catalog of errors to try to give them little weight in our daily life.

The world of fallacies belongs more to the world of philosophy and epistemology than to that of psychology, but while philosophy studies the fallacies themselves, from psychology one can study the way in which they are. used. Seeing how much false arguments are present in the speeches of people and organizations gives us an idea of ​​how the thought behind them more or less fits the paradigm of rationality.

The main types of errors

The list of errors is very long and some of them may not yet have been discovered in very minor or little studied cultures. However, some are more common than others, so knowing the main types of errors can serve as a reference to be able to detect violations in the line of reasoning wherever they happen.

Below you can see a collection of the most famous errors. Since there is no single way to classify them to create a spurious type system, in this case they are classified according to their belonging to two relatively easy to understand categories: the non-formal and the formal.

1. Non-formal errors

Non-formal fallacies are those in which the error of reasoning has to do with the content of the premises. In this type of error, what is expressed in the premises does not allow us to come to the conclusion we have reached, whether the premises are true or not.

In other words, it appeals to irrational ideas about how the world works to make it seem like what is being said is true.

1.1. Lies and ignorance

In the ad ignorantiam error, one tries to take for granted the veracity of an idea by the simple fact that one cannot prove that it is false..

The famous Flying Spaghetti Monster meme is based on this type of error: how not to show that there is no invisible being composed of spaghetti and meatballs that is also the creator of the world and its inhabitants, must be real.

1.2. Shame error

Ad verecundiam error, or error of authority, links the veracity of a proposition to the authority of the defender, as if this offered an absolute guarantee..

For example, it is common to argue that Sigmund Freud’s theories of mental processes are valid because their author was a neurologist.

1.3. Argument to deduce

In this type of error, we are trying to show that the validity or otherwise of an idea depends on whether what can be inferred from it is desirable or undesirable..

For example, a call for consequences would be to take for granted that the chances of the military staging a coup in a country are very low because the reverse scenario would deal a heavy blow to citizens.

1.4. hasty generalization

This error is a generalization not based on sufficient data.

The classic example is found in stereotypes about people in certain countries, which can lead them to mistakenly think, for example that if someone is Scottish, they must be characterized by their gaseous character.

1.5. The straw man’s mistake

In this error, the opponent’s ideas are not criticized, but a caricatured and manipulated image of them..

An example would be found in a line of argument in which a political formation is criticized for being nationalist, characterizing it as something very close to what Hitler’s party was.

1.6. After that, therefore, for that

This is a type of error in which it is assumed that if one phenomenon occurs after another, it is caused by it, in the absence of additional evidence to indicate that it is so..

For example, one could try to argue that the sudden increase in the price of an organization’s shares occurred because the start of the big game hunting season has already reached Badajoz.

1.7. False currant

By means of this error, the veracity of some ideas or conclusions is denied, highlighting the negative characteristics (More or less distorted and exaggerated) of those who defend them, rather than criticizing the idea itself or the reasoning that led to it.

An example of this error would be found in a case where someone despises the ideas of a thinker by arguing that he does not care about his self-image.

However, you have to know how to distinguish this type of fallacy from legitimate arguments referred to the characteristics of a particular person. For example, appealing to the lack of academic studies of a person speaking about advanced concepts of quantum physics may be considered a valid argument, since the information provided relates to the topic of the dialogue.

2. Formal errors

Formal errors are not because the content of the premise does not allow the conclusion to be reached, but because the relation between the premises makes the inference invalid.

This is why their errors do not depend on the content, but on how the premises are related, and are not wrong because we have added irrelevant and unnecessary ideas to the reasoning, but because there is no no consistency in the arguments we use.

Formal error can be detected by substituting all elements of the premises for the symbols and checking whether the reasoning conforms to the logical rules.

2.1. Background disclaimer

This type of error is part of a conditional like “if I give him a gift, he will be my friend”, And when the first item is refused, we mistakenly deduce that the second is also refused: “If I don’t give him a gift, he won’t be my friend.”

2.2. Affirmation of the consequent

In this type of error, we also start with a conditional, but in this case, the second element is stated and inferred so incorrect. that the antecedent is true:

“If I approve, he uncorked the champagne.”

“Check out the champagne, then I approve.”

2.3. Average not distributed

In this error the mean of a syllogism, which is what connects two propositions and does not appear in the conclusion, Does not cover all parts of the set in the premises.


“Every Frenchman is European.”

“Some Russian is European.”

“So some Russian is French.”

Bibliographical references:

  • Clark, J., Clark, T. (2005). Smokehouse! The skeptic’s field guide to detecting thinking errors. Brisbane: Clever Books.
  • Comesaña, JM (2001). Informal logic, errors and philosophical arguments. Buenos Aires: Eudeba.
  • Walton, D. (1992). The place of emotion in the plot (in English). Pennsylvania State University Press.

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