Formal & Informal Fallacies

Study Notes on Logical Fallacies: Formal & Informal Fallacies

UGC NET Syllabus of Logical Reasoning

What are fallacies?

Fallacies are errors in arguments that deceive our minds. It is a defect in an argument that consists of something other than merely false premises.

As we see, fallacies can be committed in many ways, but usually, they involve either a mistake in reasoning or the creation of some illusion that makes a bad argument appear good or bad (either).

An argument is valid when the truth of the premises guarantees the truth of the conclusion. The process that gives no rational grounds for accepting the conclusion is a defective form of an argument known as a fallacy.

Fallacies can be used positively, to avoid or expose error or they can be used for negative means, to deceive.

[ ] Ethos- ethos is an argument that appeals to ethical authority or credibility.

[ ] Pathos- pathos is an argument that appeals to emotions.

Fallacies are usually divided into two groups.

Formal and Informal Fallacies

A formal group– It may be identified through mere inspection of the form of structure of an argument.

  • [ ] In the case of formal fallacies, the conclusion does not follow from the given premises or proposition. The relation depicted in such an argument is not valid and supported by the given premises.
  • [ ] Formal fallacies can be the result of poor logic.
  • [ ] Informal fallacy’s error is in structure.

Informal fallacy-. Informal fallacies are the result of wrong information, assumptions, misuse of language, lack of evidence, or wrong analogy.

Informal fallacies are a form of incorrect argument in natural language. In this, unlike formal fallacies, the source of error is not just due to their form but can also lie in their content and context.

  • [ ] It will give an appearance of being correct despite being incorrect and thereby seduces into committing and accepting that this is true.
  • [ ] It is a fallacy in meaning. You’ll think that the premises follow the conclusion but there will be an error.

Let’s first discuss what is the difference between formal and informal fallacy

[ ] In the formal fallacy -premises will not follow the conclusion and you will easily find that there is an error in the statement.

[ ] In the informal fallacy -it will usually give an appearance of being correct and thereby it will persuade us into committing and accepting them.

Types of informal fallacies

#Ad ignorantiam

It is an appeal to ignorance. This fallacy is usually committed by us because of ignorance of the truth. We tend to commit this fallacy because it is not proven by anyone till now.

For example- Shyam said to Mohan that he does not believe in God.

When Mohan asked him the reason he said ” Because science failed to give any valid proof of the existence of God.”

Here we can simply say that Mohan has committed the fallacy of ad ignorantiam. We are ignorant of something does not mean it is not possible. Maybe in the coming future science will prove the existence of God.

#Ad populam

It is a proposition which we accept just because everyone else is accepting the same thing.
If everyone is doing one thing, it does not guarantee the rightness of that thing.

For example- If everybody is driving the car at a 200 km per hour speed that does not mean it is legal to drive a car at this speed. It will still be considered wrong.

# Ad verecundlam

This is also called “appeal to authority”. Accepting something because it is coming from some authority.

For example- if Deepika Padukone says the secret of my beauty is Lux, that does not ensure at all that using Lux will surely give the same beauty to everyone.

In this type of fallacy, we do not apply any kind of logic. We blindly follow some authority without giving any logic.

#Hasty generalization fallacy

also called ” converse accident “. Coming to a conclusion without any evidence. or Drawing conclusions from incomplete information.

Hasty generalization is a policy that affects inductive generalizations. The fallacy occurs when there is a reasonable likelihood that the sample is not representative of the group. Such a likelihood May arise if the sample is either too small or not when only selected.

#Strawman fallacy

When you know the other person is right and you don’t have any logical counterargument to fight but to make sure that you always have an upper hand you create a whole new scenario just to win an argument is called the strawman fallacy.

The strawman fallacy is committed when an arguer distorts an opponent’s argument for more easily attacking it, demolishes the distorted argument, and then concludes that the opponent’s real argument has been demolished.

By doing so the argument is said to have set up a strawman and knocked it down, only to conclude that the real man( opposing argument) has been knocked down as well.

For example, Mr. Goldberg has argued against prayer in Public School. Mr. Goldberg advocates atheism but atheism is what they used to have in Russia. Atheism leads to the suppression of all religions and the replacement of God by an omnipotent state. Is that what we want for this country?

As this example illustrates, the kind of distortion the second arguer resorts to is often an attempt to exaggerate the first person’s argument or make it look more extreme than it is.

#Red herring fallacy– (deliberate diversion)

This fallacy is closely associated with missing the point. The arguer diverts the attention of The Reader or Listener by changing the subject to a different but subtly related one. To use the Red Herring fallacy effectively, the arguer must change the original subject of the argument without The Reader or listener noticing it.

For example- Boy- Mom, I want that toy.

Mother- Hey, let’s go home, yummy food is waiting for you.

Here you can see that mother has changed the entire topic deliberately.

# Argument against the person(argumentum ad Hominem)

This fallacy always involves two arguments. One of them advances either directly or implicitly a certain argument, and the other than a response by directing his or her attention, not to the first person’s argument but the first person himself.

For example- If a politician is speaking well and giving a brilliant speech with logical reason another politician who does not have anything to say in opposition says “you can’t control the nation. Your daughter eloped with someone else.

This is clearly attacking personally.

2nd example- You cannot come first in class because you are ugly.

Here we can see that coming first or last in class has nothing to do with being ugly or beautiful but the opponent has nothing to say against his intelligence, so he attacks him personally.

# Missing the point– (ignoratio elenchi)

The arguer is ignorant of the logical implication of his or her premises and, as a result, draws a Conclusion that misses the point entirely.

This fallacy occurs when the premises of an argument support one particular conclusion but then a different conclusion often vaguely related to the correct conclusion is drawn.

For example- Crimes of theft and robbery have been increasing at an alarming rate lately. The conclusion obvious: we must reinstate the death plenty immediately “

In the above statement at least two correct conclusions are implied by the premises of the first argument 1. Either we should provide increased police protection in vulnerable neighborhoods or 2.we should initiate programs to eliminate the causes of the crimes.

Reinstating the death penalty is not a logical conclusion at all. Among other things, theft and robbery are not capital crimes.

#Complex Question

When someone invites 2 or 3 questions in one single question.

The fallacy of complex questions is committed when in a single question, more questions are asked and a single answer is then applied to both questions.

When the respondent answers are added to the complex question, an argument emerges that establishes the presumed condition.

This argument is usually intended to trap the respondent into acknowledging something that he or she might otherwise not want to acknowledge.

For example- Have you stopped cheating on exams?

Now let us suppose the respondent answers “yes” to the question.

Therefore, it follows that you have cheated in the past.


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