404. Consider the following argument:—
Granted that A is B, to prove that B is A. B (like everything else) is either A or not A. If B is not A then by our first premiss we have the syllogism—A is B, B is not A, therefore, A is not A, which is absurd. Hence it follows that B is A. [Professor Jastrow, in the Journal of Education February, 1897.]
405. Examine the following argument:—
It is impossible to prove that society can continue to exist without competition unless you can also prove that the absence of competition would not lead to the deterioration of individuals; for a society whose members deteriorate cannot long continue to exist. [M.]
406. Express the following propositions in their simplest logical form; examine their mutual consistency or inconsistency, and the validity of the final conclusion:—
Some of Mr N’s published views are new, and some true; in fact, they are all one or the other; and, though it cannot be maintained in general that a view that is not new is on that account necessarily not true, yet it can be confidently asserted that every possible false view on this subject was propounded by some one or other before Mr N. wrote: from which it would appear that while it may or may not be that Mr N.’s views are all new, it is certain that they are all true. [J.]
439 407. Examine technically the following arguments:—
(a)
“’Tis only the present that pains,
And the present will pass.”
(b) All legislative restraint is either unjust or unnecessary; since, for the sake of a single man’s interests, to restrain all the rest of the community is unjust, and to restrain the man himself is unnecessary.
(c) Only Conservatives—and not all of them—are Protectionists; only Liberals—and not all of them—are Home Rulers; but both parties contain supporters of women’s franchise. Hence only Unionists—and not all of them—are Protectionists, while the supporters of women’s franchise contain both Unionists and Free-traders.
(d) No school-boy can be expected to understand Constitutional History, and none but school-boys can be expected to remember dates; so that no one can be expected both to remember dates and to understand Constitutional History.
(e) To be wealthy is not to be healthy; not to be healthy is to be miserable; therefore, to be wealthy is to be miserable.
(f) Whatever any man desires is desirable; every man desires his own happiness; therefore, the happiness of every man is desirable. [J.]
408. Examine the validity of the following arguments:—
(1) I knew he was a Bohemian, for he was a good musician, and Bohemians are always good musicians.
(2) Bullies are always cowards, but not always liars; liars, therefore, are not always cowards.
(3) If all the soldiers had been English, they would not all have run away; but some did run away; and we may, therefore, infer that some of them at least were not English.
(4) None but the good are really to be envied; all truly wise men are good; therefore, all truly wise men are to be envied.
(5) You cannot affirm that all his acts were virtuous, for you deny that they were all praiseworthy, and you allow that nothing that is not praiseworthy is virtuous.
(6) Since the end of poetry is pleasure, that cannot be unpoetical with which all are pleased.
(7) Most M is P, Most S is M, therefore, Some S is P. 440
(8) Old Parr, healthy as the wild animals, attained to the age of 152 years; all men might be as healthy as the wild animals; therefore, all men might attain to the age of 152 years.
(9) It is quite absurd to say “I would rather not exist than be unhappy,” for he who says “I will this, rather than that,” chooses something. Non-existence, however, is no something, but nothing, and it is impossible to choose rationally when the object to be chosen is nothing.
(10) Because the quality of having warm red blood belongs to all known birds, it must be part of their specific nature; but unknown birds have the same specific nature as known birds; therefore, the quality of having warm red blood must belong to the unknown as well as the known birds, i.e., be a universal and essential property of the species. [K.]