UGC NET Study Notes on Fallacies

By Mohit Choudhary|Updated : August 8th, 2022

The fallacy is an important topic under Logical Reasoning. In UGC NET Paper 1 Exam there is always a question from fallacy topic. So, Guys read these notes now and prepare this topic right now.

Fallacies are errors in an argument that deceives the mind.  An argument consists of a set of statements, premises and conclusion. An argument is valid when the truth of the premises guarantees the truth of the conclusion. The premises that give no rational grounds for accepting the conclusion are defective forms of argument know as fallacies. Fallacies can be used positively, in order to avoid or expose error or it may be used for negative means, in order to slyly deceive.

An argument may be fallacious in 3 ways-

  1. Material- errors in material content through misstatement of facts.
  2. Verbal- incorrect use of terms.
  3. Formal- errors in structure through the use of an improper process of inference.

Types of Fallacies

Formal Fallacy

Formal Fallacies are those which have errors in the form, arrangement and technical structure of an argument. Real question is not if a conclusion is true or false, but whether the structure of the argument is correct or incorrect, valid or invalid. The concluding statement of an argument may be objectively true, even if the argument is formally invalid or the concluding statement may be objectively false, though the argument is formally valid.

Here are some examples-

Formally Valid arguments:

      A. True and Valid:

     All men are mortal.

     Suhail is a man.

     Therefore Suhail is mortal.

Above example is a valid argument since all men are mortal which thereby infer Suhail is mortal.

      B. False but Valid:

      All men are green.

      Suhail is a man.           

      Therefore Suhail is green.

Here, the first statement is false (as men are not green) but the structure of the argument is valid i.e. if all men are green, thereby Suhail is green.

 Formally Invalid Arguments:

     C. False and Invalid:

     Some men are green.

     Suhail is a man.

    Therefore Suhail is green.

     D.True but Invalid:

      Some men are mortal.

      Suhail is a man.

    Therefore Suhail is mortal.

In examples c) and d), the first statement mentions some men and not all men. So, one could accurately remark from the first statement that Suhail might probably be green or mortal, but he could not exactly claim that Suhail necessarily is green or mortal.

From the above examples, we can infer that formal fallacies are those arguments which are invalid, where the concluding statement does not essentially follow from the statements preceding it. The concluding statement may actually be objectively true, but its truth does not depend on or follow from the other statements. A change in the actual terms used in an argument may affect the actual truth value of the argument, but a change in terms will not affect the validity or invalidity of the argument. All men including Suhail are truly mortal; but all men including Suhail are not truly green. If all men were green, then Suhail would be also green. But if only some men were green, then Suhail would not necessarily be green.

 Types of formal fallacies

  • Illicit conversation

The Formal fallacy where the subject and the predicate terms of the proposition are switched in the conclusion, in a proposition that uses “all” in its premise or “some/not”

 For Example

  1. All P are Q,

Therefore, all Q are P.

This is fallacy due to the fact “all” Q are not P just because “all” P are Q. Here predicate terms of the proposition i.e. P and Q  are switched which results in a fallacy.

  • Illicit contraposition

It is formal fallacy in which switching the subject and predicate terms of a  proposition, then negating each which results in an invalid argument form.

Examples include-

  1. No S are P

Therefore, no non-P are non-S.

     2. Some S are P

Therefore, some non-P are non-S.

In both of the above examples, subject and predicate terms are switched( S and P) and negated to give a fallacy.

  • Fallacy of the undistributed middle

It is a formal fallacy that is committed when the middle term in a syllogism is not distributed in either the minor premise or the major premise. It is thus a syllogistic fallacy.

For example,

P1- All students carry backpacks.

P2- My grandfather carries a backpack.

Therefore, my grandfather is a student.

In this example, the middle term i.e. backpacks carrier not distributed because neither of its uses applies to all backpack carriers. Therefore it can't be used to connect students and my grandfather - both of them could be separate and unconnected divisions of backpack carriers.

  • Existential Fallacy

A formal fallacy in which a syllogism uses two universal premises (all) to arrive at a particular (some) conclusion.

For example,

All babysitters have pimples.

All babysitters club members are babysitters.

Therefore, some babysitter club members have pimples.

In this case, two universal premises i.e. all babysitters and all babysitter club are used to arriving at a conclusion that some babysitter has pimples. This is called an existential fallacy.

Hope you guys now have a better understanding of the topic of Fallacies. Must visit for the Part II of this series. If you have any other query, please comment.

Study Notes on Fallacies for UGC NET (Part 2)

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