Structure of a Categorical Syllogism
-  The Parts  -

Each syllogism has three propositions. Because every proposition has two terms, there could be six distinct terms here. However, there are only three--the major term, the minor term, and the middle term.

Example:

All whales are animals that breathe by means of lungs.
All whales are mammals.
All whales are animals that breath by means of lungs.

The major term of this argument is "animals that breathe by means of lungs."

The major premise is the premise that contains the major term-- "All mammals are animals that breathe by means of lungs."

The minor term is the term that occurs in the subject of the conclusion.

Example:

All mammals are animals that breathe by means of lungs.
All whales are mammals.
All whales are animals that breathe by means of lungs.
The minor term of this argument is "whales." The minor premise is the premise that contains the minor term-- "All whales are mammals."

The middle term occurs once in each of the premises, and it serves to link together the major and minor terms. In this case, the middle term is "mammals."

Example:

All mammals are animals that breathe by means of lungs.
All whales are mammals.

All whales are animals that breathe by means of lungs.

The minor term of this argument is "whales."

The minor premise is the premise that contains the minor term-- "All whales are mammals."

The middle term occurs once in each of the premises, and it serves to link together the major and minor terms.

Example:

All mammals are animals that breathe by means of lungs.
All whales are mammals.

All whales are animals that breathe by means of lungs.

In this case, the middle term is "mammals."


Comprehension Questions
1 How many terms are there in a categorical syllogism?
a) 6
b) 2
c) 3
d) 4
2 Which term in a categorical syllogism occurs in the subject of the conclusion?
a) the major term
b) the minor term
c) the middle term
3 Which term in a categorical syllogism occurs in the predicate of the conclusion?
a) the major term
b) the minor term
c) the middle term
4 Which term in a categorical syllogism occurs in each premise and serves to link together the other two terms?
a) the major term
b) the minor term
c) the middle term
5 What is the major term of the following categorical syllogism?

No horned animal is a predator
All moose are horned animals


No moose is a predator
a) horned animal
b) predator
c) moose
6 What is the minor term of the following categorical syllogism?

No Marxist advocates private property
All conservatives advocate private property


No conservative is a Marxist.
a) Marxist
b) advocates private property
c) conservatives
7 What is the major term of the following categorical syllogism?

All mammals are animals that breathe by means of lungs
All whales are mammals


All whales are animals that breathe by means of lungs
a) mammals
b) animals that breathe by means of lungs
c) whales
8 What is the middle term of the following categorical syllogism?

No horned animal is a predator
All moose are horned animals


No moose is a predator
a) horned animal
b) predator
c) moose
9 What is the middle term of the following categorical syllogism?

No Marxist advocates private property
All conservatives advocate private property


No conservative is a Marxist
a) Marxist
b) advocates private property
c) conservatives
10 What is the minor term of the following categorical syllogism?

All mammals are animals that breathe by means of lungs
All whales are mammals


All whales are animals that breathe by means of lungs
a) mammals
b) animals that breathe by means of lungs
c) whales


The Mood | The Figure

Assessment of Categorial Syllogisms by Rules

© Copyright 1998, W.W. Norton & Co.