+Theme XCVIII.+—Write a paragraph proving the truth of one of the following propositions:—
1. Labor-saving machinery is of permanent advantage to mankind.
2. New Orleans will some day be a greater shipping port than New York.
3. Poetry has a greater influence on the morals of a nation than prose writing.
4. Boycotting injures innocent persons and should never be employed.
5. Ireland should have Home Rule.
6. The President of the United States should be elected by the direct vote of the people.
(Consider your argument with reference to the suppressed premises.)
+180. Errors of Deduction.+—The deductive method of reasoning, if properly used, is effective, but much care needs to be taken to avoid false conclusions. A complete exposition of the variations of the syllogism is not necessary here, but it will be of value to consider briefly three chief errors.
If the terms are not used with the same meaning throughout, the conclusion is valueless. A person might agree with you that domestic arts should be taught to girls in school, but if you continued by saying that scrubbing the floor is a form of domestic art, therefore the girls should be taught to scrub the floor, he would reject your conclusion because the meaning of the term domestic art as he understood it in the first statement, is not that used in the second.