Question

State the obverses of the following propositions:
(i) Some men have taste for literature.
(ii) No men is perfect.
(iii) Some despots are not cruel.

Hint:

Obversion involves switching the quality (affirmative to negative) and replacing the predicate with its complement.

Answer 1

Obversion:
Obversion involves two steps: changing the quality of the proposition (affirmative to negative or vice versa) and replacing the predicate with its complement.
Obverse of (i):
The original proposition is:
Some men have taste for literature. The obverse of this proposition will be:
Some men do not have non-taste for literature. This involves changing the quality (affirmative to negative) and replacing the predicate ("taste for literature") with its complement ("non-taste for literature").
Obverse of (ii):
The original proposition is:
No men is perfect. The obverse of this proposition will be:
All men are imperfect. This involves changing the quality (universal negative to universal affirmative) and replacing the predicate ("perfect") with its complement ("imperfect").
Obverse of (iii):
The original proposition is:
Some despots are not cruel. The obverse of this proposition will be:
Some despots are non-cruel. This involves changing the quality (affirmative to negative) and replacing the predicate ("cruel") with its complement ("non-cruel").
Conclusion: The obverses of the three propositions are obtained by changing the quality and replacing the predicate with its complement.