Which of the following codes contains only the correct statements? Statements:…
2013
Which of the following codes contains only the correct statements?
Statements:
(i) A Venn diagram provides a clear visual method of notation.
(ii) A Venn diagram is a direct method for testing the validity of categorical syllogisms.
(iii) In the Venn-diagram method, both the premises and the conclusion of a categorical syllogism are entered into the same test diagram.
(iv) Three overlapping circles are used to test a categorical syllogism.
Codes:
Answer: B. (i), (ii) & (iv) — ConceptA three-term categorical syllogism is represented by three overlapping circles, one for each term. To test validity, diagram the premises first; then…
- A.
(i), (ii) & (iii)
- B.
(i), (ii) & (iv)
- C.
(ii), (iii) & (iv)
- D.
(i), (iii) & (iv)
Show answer & explanation
Correct answer: B
Concept
A three-term categorical syllogism is represented by three overlapping circles, one for each term. To test validity, diagram the premises first; then inspect whether the conclusion is already forced by the completed premise diagram. The conclusion is not added as another premise.
Application
Statement (i) describes the visual clarity of Venn notation and is accepted.
Statement (ii) identifies its direct use for checking categorical-syllogism validity and is accepted.
Statement (iii) says that the premises and conclusion are entered into the same test diagram. In the validity test, only the premises are entered; the conclusion is checked against their diagram, so this statement is not accepted.
Statement (iv) follows from the three terms of a categorical syllogism: one circle represents each term, giving three overlapping circles.
Cross-check and result
If the conclusion had to be entered into the diagram, the procedure would assume what it is meant to test. Therefore the correct set is (i), (ii), and (iv).