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Mood and Figure

Structure of Categorical propositions | Mood and Figure

UGC NET Exam Study Notes on “Structure of Categorical propositions” and “Mood and Figure”

Topics Based on UGC NET Syllabus of Logical Reasoning

Whats is the Categorical Propositions?

A “Subject” of a sentence is the thing that has some property or class is being attributed to, the “Predicate” is the property or class that is being attributed to the subject, and the “Copula” is the word that links the two together.

For Example – All dogs are mammals

Here, “dogs” is the subject, “mammals” is the predicate, and “are” is the copula. This particular statement about bunnies has a certain form, the form of a categorical proposition.

So in simple words, “A proposition that relates two classes or categories” is known as a Categorical Proposition.

If you look at the above example in addition to subject, predicate and coupla it also has “quantifiers” that tells you HOW MANY of the subjects are being referred into the statement.

Categorical propositions tell us one of four things:
(1) ALL members of the subject class are included in the predicate class.
(2) NONE of the members of the subject class are included in the predicate class.
(3) SOME of the members of the subject class are included in the predicate class.
(4) SOME of the members of the subject class are NOT included in the predicate class.

Here are some examples of each of these 4 kinds of the categorical proposition:
(1) All dogs are mammals.
(2) No dogs are reptiles.
(3) Some dogs are cute.
(4) Some dogs are not potty-trained.


Here is the FORM of each of these 4 kinds of categorical proposition:
(1) All S are P.
(2) No S are P.
(3) Some S are P.
(4) Some S are not P

Now, let’s go over some definitional terms: Categorical statements each have a quantity and a quality.


Quantity: Refers to HOW MUCH of the subject class is included in the predicate class.

Quantity is either:
(a) Universal – Tells us something about how ALL of the subjects are related to the predicate.
(b) Particular – Tells us how SOME of the subjects are related to the predicate.


Quality: Refers to whether the proposition is AFFIRMING something or DENYING something of a subject.

Quality is either:
(a) Affirmative – Members of the subject ARE included in the predicate.
(b) Negative – Members of the subject are NOT included in the predicate.

For instance, of the 4 kinds of the categorical proposition we discussed above:

PropositionQuantityQualityLetter
All S are P.universalaffirmativeA
No S are P.universalnegativeE
Some S are P.particularaffirmativeI
Some S are not P.particularnegativeO
For shorthand, it is common to refer to each of these types of the proposition by a letter;
Those letters are A, E, I, and O.

Now, you must be wondering what are these “A, E, I, O”, Let’s understand with more examples.

  • A is universal positive.
    • All apples are good.
    • All milk is white .
  • E  Is universal negative.
    • No bread is butter.
    • No egg is white.
  • I is particular positive
    • Some apples are good.
    • Some bread is butter.
    • Some eggs are white.
  • O is particular negative
    • No apple are good.
    • No bread is butter.
    • NO eggs are white.

Categorical Syllogisms

Syllogism: An argument consisting of three statements: TWO premises and ONE conclusion.

Categorical syllogism: A syllogism consisting of three categorical propositions, and containing THREE DISTINCT TERMS, each of which appears in exactly two of the three propositions.

So, what are these 3 terms mentioned? Consider the following syllogism:

  • All mammals are creatures that have hair.
  • All dogs are mammals.
  • Therefore, all dogs are creatures that have hair.

There are THREE different terms in this argument (besides the quantifiers and the copulas). The three different terms are called the “major term”, the “minor term”, and the “middle term.”

Notice that the conclusion only contains TWO of the three terms but one of the terms is
found only on the premises.

Here are some definitions:
Major Term: The predicate term of the conclusion (above, “creatures that have hair”)
Minor Term: The subject term of the conclusion (above, “dogs”)
Middle Term: The term that does NOT appear in the conclusion (above, “mammals”)

Finally, note that premise 1 contains the major term, while premise 2 contains the minor term. Premise 1 is therefore called the major premise, while premise 2 is called the minor premise. The standard form demands that the major premise (i.e., the one containing the major term) ALWAYS be listed first.

Easy to grasp right? We will cover a very simple trick to remember these “there terms” and this question is the favourite of a UGC NET examiner from the last few years.

Warning!  Tricks to remember “MAJOR”, “MINOR” and  “MIDDLE” terms.  Let’s take another example.

  • Statement 1 – All A are B .
  • Statement 2 – All B are C .
  • Conclusion – All A are C .

Here – 

  1. Statement first is also known as premises 1 and Statement second is also known as premises 2.
  2. In the above statement “B” is the middle term which is also known as cancelling term and in Indian logic known as “Hetu”.
  3. In the above statement “A” is minor term and “C” is major term.

Now, how to find out which one is major term, minor term and middle term?

MAJOR TERM –   the term in a syllogism that is the predicate of the conclusion is known as major term .

You should always check “conclusion” for major term. For example is above statement, the conclusion is All A are C . So, the last term in the conclusion that is C is your major term. 

Example 1– If the conclusion is “ All parrots are green”

So, in the above statement “green” is major term.

Example 2– No apple is good .

So, in the above statement “good” is your major term .

Tip– second word of your conclusion is always your major term.

MINOR TERM- the term in a syllogism that is the subject of the conclusion is known as Minor term. It is also known as subject.

You always should look into conclusion to find out Minor term. Remember- major term was the last term of conclusion but Minor term is the first term in the conclusion .

This Minor term is known as “paksha” .

Remember it as – it is in the increasing order that is it goes from small to big. In the above given statement our conclusion is  “All A are C”  so, in this statement “a” is minor term because A is the first term in the conclusion.  

For more clarity have a look on the given examples :

1st example –  No blackboard is green

  • Minor term –  blackboard
  • Major term – green

2nd example – some bread is butter

  • Minor term- bread
  • Major term – butter

MIDDLE TERM- In syllogism, a middle term is a term that appears in both premises but not in the conclusion of a categorical syllogism. This is also known as cancelling term and Indian logic this is known as “Hetu” or “Reason”.

To find out which one is middle term, you always should look into premises. Middle term never appears in the conclusion.

The term which is present in both premises- premises 1 and premises 2 is called middle term.

The mutual term present in both statements are called middle term.

Example 1

  • Statement1 – some breads are milk .
  • Statement2- some milk is butter .

Conclusion – some butter are  bread .

In this given statement “ milk” is the mutual word available in both statements.  So, milk is our middle term . Observe carefully “ Milk is not present in conclusion”.

 

Mood and Figure

Now that we know the correct FORM of categorical syllogisms, we can learn some tools that will help us to determine when such syllogisms are valid or invalid.

All categorical syllogisms have what is called a “mood” and a “figure.”

What are mood and Figures?

Mood: The mood of a categorical syllogism is a series of three letters corresponding to the type of proposition the major premise, the minor premise, and the conclusion is (A, E, I, or O).

Mediaeval logicians invented a simple method of labelling the various forms in which a categorical syllogism may occur by simply stating its mood and figure.

Mood –  It usually depends upon the type of propositions (A, E, I, O).

Figure – It depends on the arrangement of the middle term in the proposition.

The figure of the syllogism is based on the arrangement of Subject and predicate and middle term or the common term.

The different types of figures in syllogism are:

First figureSecond figureThird figureFourth figure
M-PP-MM-PP-M
S-MS-MM-SM-P
S-PS-PS-PS-P
In this above table: M stands for “middle term”, S stands for “subject”, P stands for “predicate”

Tips to remember this above table-

  • In first figure – M makes a sort of vertical right hand like this “ \”.
  • In second figure- M makes a straight hand in right direction like this “|” in right hand side.
  • In Third figure- M makes a right hand is left direction like this “|” in left hand side.
  • In Fourth figure- M makes a sort of vertical left hand like this “/” .

There is 256 combination of the different forms of mood and figure. Out of these 256 combinations, only 15 were found to be valid by Aristotle. There are 9 conditionally valid argument forms for categorical syllogisms in addition to the 15 unconditionally valid argument forms: The valid combinations are given below in the table.

Unconditionally Valid Forms: There are 15 combinations of mood and figure that are valid from the Boolean standpoint (we call these “unconditionally valid” argument forms).

The below chart depicts ALL of 15 the unconditionally valid argument forms

First figureAAA,EAE,AII,EIO
Second figureEAE,AEE,EIO,AOO
Third figureIAI, AII, OAO, EIO
Fourth figureAEE,IAI,EIO

Recall this argument from earlier:

  1. All mammals are creatures that have hair.
  2. All dogs are mammals.
  3. Therefore, all dogs are creatures that have hair.

Its mood is “AAA” since all three propositions are “A” propositions (i.e., they are all of the forms “All S are P”). Its figure is “figure 1”

Points to keep in mind( only for the first figure)
  1. If both the premises are positive (A or I), then the conclusion will also be positive (A Or I)
  2. If one of the premises is negative (E or O), then the conclusion will also be negative (E or O).
  3. If one of the premises is particular (I or O), then the conclusion will also be particular (I or O)
  4. If one of the premises is particular negative (O) , then the conclusion will aslo be particular negative .
  5. If one of the premises is particular and the second one is negative, then also the conclusion will be particular negative (0).

Some of the mood and figure examples

Examples of the First figure

AAA

  • Major premises : All B are C.
  • Minor premises : All A are B.
  • Conclusion :  All A are C.

EAE

  • Major premises : No B are C.
  • Minor premises : All A are B.
  • Conclusion : No A are C.

AII

  • Major premises : All B are C.
  • Minor premises : Some A are B.
  • Conclusion : Some A are C.

EIO

  • Major premises : No B are C.
  • Minor premises : some A are B.
  • Conclusion : some A are not C.

Special cases

AAI

  • Major premises :All B are C.
  • Minor premises : All A are B.
  • Conclusion : Some A are not C.

EAO

  • Major premises : No B are C.
  • Minor premises : All A are B.
  • Conclusion : Some A are not C.

Examples of the second figure

EAE

  • Major premises : No C are B.
  • IMinor premises : All A are B
  • Conclusion : No A are C.

AEE

  • Major premises : All C are B
  • Minor premises : No A are B.
  • Conclusion :No A are C.

EIO

  • Major premises: No C are B.
  • Minor premises : Some A are B
  • Conclusion : Some A are not C.

AOO

  • Major premises : All C are B .
  • Minor premises : Some A are not B.
  • Conclusion : Some A are not C.

Special cases

AEO

  • Major premises : All C are B.
  • Minor premises : No A are B.
  • Conclusion : Some A are not C

EAO

  • Major premises : No C are B.
  • Minor premises : All A Are B.
  • Conclusion : Some A are not C.

Examples of the Third figure

IAI

  • Major premises : Some B are C.
  • Minor premises : All B are A.
  • Conclusion : Some A are C.

AII

  • Major premises: All A are C.
  • Minor premises :Some B are A.
  • Conclusion: Some A are C.

OAO

  • Major premises : Some B are not C.
  • Minor premises: All B are A.
  • Conclusion: Some A are not C.

EIO

  • Major premises : No B are C.
  • Minor premises : some B are A.
  • Conclusion : some A are not C

Special cases

AAI

  • Major premises : All A are C.
  • Minor premises :All B are A.
  • Conclusion : Some A are C.

EAO

  • Major premises :No B are C.
  • Minor premises :All B are A.
  • Conclusion : some A are not C.

Examples of the Fourth figure

AEE

  • Major premises : All C are B.
  • Minor premises : No B are A.
  • Conclusion : No A are C

IAI

  • Major premises : Some C are B.
  • Minor premises : All B are A .
  • Conclusion : Some A are C .

EIO

  • Major premises : No C are B .
  • Minor premises : Some B are A.
  • Conclusion : Some A are not C.

Special cases

AEO

  • Major premises :All C are B.
  • Minor premises :No B are A.
  • Conclusion : Some A are not C.

EAO

  • Major premises : No C are B
  • Minor premises :All B are A.
  • Conclusion : Some A are not C.

AAI

  • Major premises : All C are B.
  • Minor premises : All B are A.
  • Conclusion :Some A are C.

Solved MCQ Based on Mood and Figure

Identify the mood and figure of the following syllogism:

Question 1 –  

  • some B are A
  • All B are C
  • Some A are  C

Options :

  1. IAI – 3 [Answer]
  2. IAI – 2
  3. IAI – 1
  4. IAI – 4

Question 2 –

  • No A are B
  • ALL c are B
  • NO A are C

Options :

  1. EAE -3
  2. EAE – 2 [Answer]
  3. EAE – 1
  4. EAE – 4

Question- 3

  • All C are A
  • Some B are A
  • Some C are A

Options :

  1. First [Answer]
  2. Second
  3. Third
  4. Fourth

References –

  1. Study Notes from – https://rintintin.colorado.edu/~vancecd/phil1440/notes.html

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