12. QUESTIONS FOR ORIGINAL THOUGHT AND INVESTIGATION.
(1) Give an illustration of a syllogism in the fourth figure which might just as well be written in the first figure.
(2) May a syllogism, which is invalid in the fourth figure, be made valid by writing it in the form of the first figure? Prove it.
(3) Show why it is impossible to apply all the rules of the ***
(4) Show the difference between a direct and an indirect proof.
(5) Show that A
A
O is valid in the first figure when the major premise (A) is co-extensive.
(6) The third figure is known as the figure of particular conclusions. Why should not the second canon of that figure be, “One premise must be particular” rather than “The conclusion must be particular?”
(7) Show that there is some ground for thinking that, as a final test, moods in the other figures should be reduced to the first.
(8) Illustrate the fact that the second figure is the figure of disproof; whereas the third is the figure of contradictions.
(9) “To be logical a syllogism must conform to one of the four figures, but this does not mean, necessarily, that all arguments must conform to some figure.” Explain this.