2. Give the logical opposites of the following propositions—
(1) Knowledge is never useless.
(2) All Europeans are civilised.
(3) Some monks are not illiterate.
(4) Happy is the man that findeth wisdom.
(5) No material substances are devoid of weight.
(6) Every mistake is not culpable.
(7) Some Irishmen are phlegmatic.
3. Granting the truth of the following propositions, what other propositions can be inferred by opposition to be true or false?
(1) Men of science are often mistaken.