If the statement "Some animals are birds" is given as false then which of the following statements can be immediately inferred to be false?
All animals are birds.
Concept: On the Square of Opposition, the universal affirmative (A) 'All S are P' and the particular affirmative (I) 'Some S are P' stand in a relation of subalternation: the truth of A implies the truth of I. Equivalently, if I is false, then A must also be false, because a universal claim cannot hold when even its weaker particular version fails.
Working: We are told 'Some animals are birds' (an I-proposition) is false. Since 'All animals are birds' (the corresponding A-proposition) would, if true, force 'Some animals are birds' to be true, the falsity of the I-statement immediately makes the A-statement false as well. Therefore 'All animals are birds' can be immediately inferred to be false.
Why the other choices are wrong:
'No animals are birds' is the contradictory of the false I-statement, so it must be true, not false.
'Some animals are not birds' is the E/O-region result that also follows as true when 'Some animals are birds' is false, so it cannot be the false one.
'Some birds fly' involves an entirely different predicate (flying) and is not logically connected to the given proposition, so its truth value cannot be inferred at all.
Takeaway: If a particular affirmative is false, its corresponding universal affirmative is necessarily false.
Correct answer: All animals are birds.
Similar Questions
In a square of opposition, if 'No animals with horns are carnivores' is false, which of the following is the correct code?
codes:
A. 'Some animals with horns are carnivores' is true.
B. 'Some animals with horns are not carnivores' is true.
C. 'All animals with horns are carnivores' is false
D. 'All the animals with horns are carnivores' is undermined.Which of the following statements are logically equivalent?
A. Some cricketers are kind men.
B. Some kind men are cricketers.
C. Some cricketers are not non-kind men.
D. Some non-kind men are not non-cricketers.
Choose the correct answer from the options given below:Which of the following statements is contrary to the statement- "No football players are kind-hearted human beings"?
If the statement-"Some athletes are kind human beings" is given as true, then which of the following statements can be immediately inferred to be false?
Which of the following statements is contradictory to the statement - "Some birds are mammals"?
If the statement - "Some animals are not birds" is given as false, then which of the following statements can be immediately inferred to be false?
Which of the following is contrary to the statement "No mammals are birds"?
Which of the following propositions can be directly inferred from the statement - "All mammals are four-legged animals?
Which of the following statements are contradictory to each other?
A. All objects are perishable.
B. Some objects are not perishable.
C. Some objects are perishable.
D. No objects are perishable.
Choose the most appropriate answer from the options given below:
Which of the following statements is contradictory to the statement-" all dogs are friendly animals" ?
Important Questions from Classical Square of Opposition
Which of the following statements are so related that they can not both be true but could both be false?
A. All Biologists are outstanding teachers.
B. Some Biologists are outstanding teachers.
C. No Biologists are outstanding teachers.
D. Some Biologists are not outstanding teachers.
Choose the correct answer from the options given below:
- Which of the following propositions are so related that they can neither be true together nor can they be false together?
A. All printers are computer peripherals.
B. Some computer peripherals are printers.
C. Some printers are not computer peripherals.
D. No printers are computer peripherals.
Choose the correct answer from the options given below: - Which of the following statements contradict each other ?
A. All ducks are birds.
B. Some ducks are birds.
C. Some ducks are not birds.
D. No ducks are birds.
Choose the most appropriate answer from the options given below : - If the statement "No birds are animals" is given as false, which of the following statements can be inferred to be true ?
A. Some animals are not birds.
B. Some birds are not animals.
C. Some animals are birds.
D. Some birds are animals.
Choose the most appropriate answer from the options given below : - Which of the following statements are sub-contraries?
A. All sparrows are birds.
B. No sparrows are birds.
C. Some sparrows are birds.
D. Some sparrows are not birds.
Choose the correct answer from the options given below:
