Under the conventional existential-import rule used in aptitude-test…
2021
Under the conventional existential-import rule used in aptitude-test syllogisms, if “All successful administrators are intelligent” is true, which of the following statements follows?
Answer: B. Some successful administrators are intelligent — CONCEPTA universal affirmative proposition has the form “All S are P”, represented as S ⊆ P. In the conventional syllogism rules used in aptitude tests, the…
- A.
No successful administrator is intelligent
- B.
Some successful administrators are intelligent
- C.
Some successful administrators are not intelligent
- D.
Some intelligent people are not successful administrators
Show answer & explanation
Correct answer: B
CONCEPT
A universal affirmative proposition has the form “All S are P”, represented as S ⊆ P. In the conventional syllogism rules used in aptitude tests, the subject class S is treated as non-empty, so the universal affirmative has existential import.
Under subalternation, an A-form proposition therefore supports the corresponding I-form proposition “Some S are P”. It does not support the contrary E-form, the contradictory O-form, or an existence claim about the part of P outside S.
APPLICATION
Let S be the set of successful administrators and I be the set of intelligent people.
The premise “All successful administrators are intelligent” gives S ⊆ I.
By the conventional existential-import assumption, S is non-empty; choose an element x in S.
Since S ⊆ I, the same element x is also in I. Hence at least one successful administrator is intelligent.
CONTRAST
“No successful administrator is intelligent” makes S and I disjoint, contrary to S ⊆ I with non-empty S.
“Some successful administrators are not intelligent” requires an element of S outside I, contradicting S ⊆ I.
“Some intelligent people are not successful administrators” needs an element in I outside S; the premise does not guarantee that region is occupied.
CROSS-CHECK
Draw the S circle entirely inside the I circle and place one witness in S. That witness necessarily lies in both circles, while no witness is forced into the I-only region.
Therefore, the statement that follows is “Some successful administrators are intelligent”.