Accept every statement below as true, whatever the real world says. Which of the conclusions must then be true?
Statements:
1. All hens are cocks.
2. No hen is a parrot.
Conclusions:
I. All cocks are hens.
II. No hen is a parrot.
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Only conclusion II follows
A conclusion follows only if it is true in every diagram that fits the statements. One diagram in which a conclusion is false is enough to reject it.
“All hens are cocks”: the circle of hens lies inside the circle of cocks
“No hen is a parrot”: the circle of parrots does not touch the circle of hens
Conclusion I: All cocks are hens. — Does not follow. “All hens are cocks” cannot be reversed: the cocks outside the hen circle are not hens.
Conclusion II: No hen is a parrot. — Follows. It repeats statement 2, which is taken to be true.