Square-of-opposition
Question 1 |
If the proposition “All men are not mortal” is true then which of the following inferences is correct ? Choose from the code given below :
1. “All men are mortal” is true.
2. “Some men are mortal” is false.
3. “No men are mortal” is doubtful.
4. “All men are mortal” is false.
1. “All men are mortal” is true.
2. “Some men are mortal” is false.
3. “No men are mortal” is doubtful.
4. “All men are mortal” is false.
1, 2 and 3 | |
2, 3 and 4 | |
1, 3 and 4 | |
1 and 3 |
Question 1 Explanation:

Question 2 |
If the statement ‘some men are honest’ is false, which among the following
statements will be true. Choose the correct code given below:
(i) All men are honest
(ii) No men are honest
(iii) Some men are not honest.
(iv) All men are dishonest.
statements will be true. Choose the correct code given below:
(i) All men are honest
(ii) No men are honest
(iii) Some men are not honest.
(iv) All men are dishonest.
(i), (ii) and (iii) | |
(ii), (iii) and (iv) | |
(i), (iii) and (iv) | |
(ii), (i) and (iv) |
Question 3 |
By which of the following proposition, the proposition “wise men are hardly afraid of death” is contradicted?
Some wise men are afraid of death. | |
All wise men are afraid of death. | |
No wise men is afraid of death. | |
Some wise men are not afraid of death. |
Question 3 Explanation:
Option ‘B’ is suitable contradicted to given proposition.
Question 4 |
If two propositions having the same subject and predicate terms are such that one is the denial of the other, the relationship between them is called
Contradictory | |
Contrary | |
Sub-contrary | |
Sub-alteration |
Question 5 |
If two propositions cannot both be false but may both be true, what is the relation between the two propositions ?
Contrary | |
Sub-contrary | |
Sub-alternation | |
Contradictory |
Question 5 Explanation:
Subcontrary:- Two prepositions can be true, but cannot be false.
Question 6 |
What is equivalent of the statement ‘All atheists are pessimists’ ?
All non-pessimists are nonatheists. | |
All non-atheists are nonpessimists. | |
All pessimists are atheists. | |
None of the above. |
Question 6 Explanation:

Question 7 |
If two propositions having the same subject and predicate terms can both be true but cannot both be false, the relation between those two propositions is called
contradictory | |
contrary | |
subcontrary | |
subaltern |
Question 7 Explanation:
Subcontrary:- Denoting the preposition can be true but cannot be false.
There are 7 questions to complete.