Discussion Forum

In the following question, three statements are given followed by four conclusions numbered I,II,III and IV. You have to take the given statements to be true even if they seem at variance with commonly known facts and then decide which of the given conclusions logically follows from the given statements disregarding commonly known facts.

Statements: All benches are desks. Some desks are roads. All roads are pillars. 

Conclusions: I. some pillars are benches. II. some pillars are desks. III. Some roads are benches. IV. No pillar is bench.

Answer:

Explanation:

All benches are desks. Some desks are roads.

Since the middle term 'desks' is not distributed even once in the premises, no definite conclusion follows.

Some desks are roads. All roads are pillars.

Since one premise is particular, the conclusion must be particular and should not contain the middle term. So, it follows that 'Some desks are pillars'. II is the converse of this conclusion and so it holds.

All benches are desks. Some desks are pillars. 

Since the middle term 'desks' is not distributed even once in the premises, no definite conclusion follows. However, I and IV involve the extreme terms and form a complernentary pair. So, either I or IV follows.