(23) Convert, if possible, the following: (1) “Some men practice sophistry.” (2) “Few men know how to live.” (3) “Some of the inhabitants are not civilized.” (4) “All the world is a stage.” (5) “None of my pupils failed.” (6) “Experience is a hard taskmaster.” (24) Why may co-extensive propositions be converted simply? (25) Describe the process of inference by contraversion. =9. PROBLEMS FOR ORIGINAL THOUGHT AND INVESTIGATION.= (1) What ground is there for the belief that immediate inference, so called, is merely a matter of the interpretation of propositions? (2) Is there any difference between reasoning and inference? (3) When the conclusion is reached that two rooms are of the same width, because each is five yards wide, what is the middle term? (4) Put in equation form: All teachers instruct, John Jones is a teacher, John Jones instructs. Show that the equations are not _absolutely true_. (5) Indicate the true relation between the subjects and predicates of the foregoing by using the algebraic signs > and <. (6) Why cannot an A be derived from an I? (7) Why cannot an O be derived from an A? (8) The basic principle of obversion is “Two negatives are equivalent to one affirmative.” Show by means of circles that this is not absolutely true; take as an illustrative proposition, “No men are not mortal.” (9) Show that agreeable and disagreeable are not contradictory terms. (10) Why should the logician class individual propositions as universal? (11) Show by circles that there is a difference in signification between, “Some men are _not wise_” and “Some men are _not-wise_.” (12) Show by circles that the O proposition cannot be converted. (13) “The I proposition cannot be contraverted.” Make this clear. (14) Is there any difference in meaning between, “All illogical work is unscholarly” and “No illogical work is scholarly?” Explain by circles. (15) State the logical process involved in passing from each proposition to its succeeding one: (1) “All men are imperfect.” (2) “No men are perfect.” (3) “No perfect beings are men.” (4) “Some not-men are perfect beings.” (5) “Some perfect beings are not-men.” (6) “Some perfect beings are not men.” (16) It is sometimes said that in sub-contraries there is really no opposition. Do you agree? Give arguments. CHAPTER 11. MEDIATE INFERENCE. THE SYLLOGISM. =1. INFERENCE AND REASONING.=