EXERCISE IN LOGICAL FALLACIES

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Analogy problems

Of the following passages, first identify those that contain arguments by analogy. For each argument by
analogy, identify the primary subject and the analogue, mention key relevant similarities and differences
between the primary subject and the analogue, and comment on the merits of the argument. If any passage
contains a fallacy such as two wrongs, slippery assimilation, or slippery precedent, point this out and
explain how the fallacy is committed in that particular case. 

1. "It is of course quite true that the majority of women are kind to children and prefer their own to other
people's. But exactly the same thing is true of the majority of men, who nevertheless do not consider that
their proper sphere is the nursery. The case may be illustrated more grotesquely by the fact that the majority
of women who have dogs are kind to them and prefer their own dogs to other people’s. Yet it is not
proposed that women should restrict their activities to the rearing of puppies."

Question: Here Shaw is alleging that other people use a faulty argument. Do you agree with him? 

(G. B. Shaw, "The Womanly Woman," in Masculine/Feminine, ed. Betty Roszak and Theodore Roszak
[New York: Harper & Row], 1969) 

2. Gordon Sinclair is a Toronto-based political commentator. The following is an excerpt from his
appearance before a Canadian Royal Commission on Violence in the Communications Indus" (1976). 

"Since your Commission has attracted so few briefs that do not complain about violence or what they call
'excess violence,' I'd like to say that without violence or its threat, we become vegetables unable to take
care of ourselves. Violence is not only useful or necessary, it is essential to human survival. Without it we
would become pitty pat cream puffs, and absence of physical violence would soon embrace mental
violence. Protest could disappear. The human is an animal and animals are at times violent by nature."
(Reprinted in the Informal Logic Newsletter, July 1983.) 

3.  Here is a piece on the subject of the moral status of animals. It was written by Lewis Carroll,
the author of Alice in Wonderland. Carroll was also a logician of considerable accomplishments. This
passage is taken from his essay, "Some Popular Fallacies About Vivisection": 

"In discussing the rights of animals, I think I may pass by, as needing to remark, the so-called right of a race
of animals to be perpetuated and the still more shadowy right of a non-existent animal to come into
existence. The only question worth consideration is whether the killing of an animal is a real infringement of
a right. Once grant this, and a reductio ad absurdum is imminent, unless we are illogical enough to assign
rights to animals in proportion to their size. Never may we destroy, for our convenience, some of a litter of
puppies, or open a score of oysters when nineteen would have sufficed, or light a candle in a summer
evening for mere pleasure, less some hapless moth should rush to an untimely end! Nay, we must not even
take a walk, with the certainty of crushing many an insect in our path, unless for really important business!
Surely all this is childish. In the absolute hopelessness of drawing a line anywhere, I conclude (and I believe
that many, on considering the point, will agree with me) that man has an absolute right to inflict death on
animals, without assigning any reason provided that it be a painless death. But any infliction of pain needs
its special justification."

(Lewis Carroll, "Some Popular Fallacies About Vivisection," The Complete Works of Lewis Carroll [New
York. Random House, 1957]) 

4. Background. Author Donald Griffin is discussing whether animals are conscious and what sorts of
thoughts they might have if they are: 

"The content of much human consciousness does not conform to objective reality. Fear of ghosts and
monsters is very basic and widespread in our species. Demons, spirits, miracles, and voices of' departed
ancestors are real and important to many people, as are religious beliefs. 

"...Yet when we speculate about animal thoughts, we usually assume that they would necessarily involve
practical down-to-earth matters, such as how to get food or escape predators.... But there is really no
reason to assume that animal thoughts are rigoristically realistic. Apes and porpoises often seem playful,
mischievous, and fickle, and anything but businesslike, practical, and objective. Insofar as animals do think
and feel, they may fear imaginary predators, imagine unrealistically delicious foods, or think about objects
and events that do not actually occur in the real world around them." 

(Donald Griffin, Animal Thinking [Cambridge, MA: Harvard University Press, 1984], pp.202-203) 

II. Post hoc and other fallacies 

For the following arguments, indicate any causal claims that appear either in the premises or in the
conclusion. It causal claims are made in the conclusion, assess the reasoning offered to support them and
say if you find examples of post hoc or objectionable cause. If causal claims are made in the premises, is
the argument an example of causal slippery slope? Why or why not? 

Note.- Some arguments may contain no causal claims, and some passages may not contain arguments. If
either of these is the case, simply note the fact and proceed to the next example. 

1. Background The author is asserting that in the period between 1980 and 1986, the quality of the
manpower enlisting in U.S. armed forces has improved. 

"People can still argue about restoring the draft, but now the arguments are about principles: How should a
democracy allot the burden of military service? Is it just and fair to leave the risk of dying to volunteers? The
debates are no longer driven by concerns about the quality of people who have volunteered. "But
manpower, though historically the most important factor in military excellence, is not the only one-and
certainly is not the principal force behind our increased spending. Pay has gone up-but not stupendously
and certainly not by as much as the quality of the force. From 1980 to 1985 personnel costs rose by less
than 20 percent, and as a share of overall defense spending, pay and benefits fell. The improvement in the
force, hard to quantify but more like 200 percent than 20, has been due partly to the severe recession of
1982, partly to a sense that the military is ‘de-civilianizing’ itself and restoring its standards and
self-esteem, and partly to the general resurgence of nationalistic pride." 

(James Fallows, "The Spend-up," The Atlantic, June 1986, p. 28) 

2. "On the one hand, although logic and common sense offer excellent solutions when they work, who has
not had the frustrating experience of doing his very best in these terms, only to see things going from bad to
worse? On the other hand, every once in a while we experience some ‘illogical’ and surprising but welcome
change in a troublesome stalemate. Indeed, the theme of the puzzling, uncommonsensical solution is an
archetypical one, reflected in folklore, fairy tales, humor, and many dreams-just as there are both popular
and more erudite conceptions of the perversity of other people, the world, or the devil to explain the
converse situation. Yet it seems that little serious and systematic inquiry has been focused on this whole
mat- ter, which has remained as puzzling and contradictory as ever." 

(Paul Watziawick, John H. Weakland, and Richard Fisch, Change. Principles of Problem Formulation and
Problem Resolution [New York: Norton, 1974], p. xiii) 

3. "For the past thirty years, six-foot-four John Wayne has stalked through the American imagination as the
embodiment of manhood .... He has left not only a trail of broken hearts and jaws everywhere, but millions of
fractured male egos which could never quite measure up to the two-fisted, ramrod-backed character who
conquered the Old West. The truth of the matter is that no man could measure up to that myth in real life-not
even John Wayne."

(Tim LaHaye, Understanding the Male Temperament [Charlotte, NC: Commission Press, 1977], p. 11) 

4. Background. This item appeared in the Oakland Press on April 6,1974, and was reprinted in the Informal
Logic Newsletter Examples Supplement for 1979: 

A Good Way to Cure Colds 

"University of Michigan medical researchers have discovered that highly educated people with low incomes
catch cold more often than others, suggesting that susceptibility to colds might depend on one’s frame of
mind. Furthermore, more people come down with colds on Monday than any other day. 

"Well, practically everybody thinks he is not being paid as much as his education calls for, and it's on
Monday mornings when this feeling becomes most acute. So obviously, it's not a germ or virus that's
causing all our colds but those cold-hearted people in the front office who never seem to realize how smart
we are. A cure for colds? One way would be to give everybody a raise and tell them to take Monday off." 

III. Evaluate the following conductive arguments. (a) State any counter considerations on which your
evaluation depends, and note whether these are your own contributions or whether they are explicitly
acknowledged by the author of the argument. (b) State whether the premises are positively relevant to the
conclusion and whether, considered together, in light of counter considerations, they provide adequate
grounds for the conclusion. (c) If you believe that you lack the background knowledge necessary to evaluate
the argument, state what sort of knowledge you would need. 

1. There is no point in giving money to charity. The charitable organizations often waste it. Besides, when
people are really needy, governments should support them and not rely on charity to do it. In addition, the
advertisements put out by some of these charities are so emotional that they are positively manipulative. 

2. The Bible is among the most trustworthy of ancient documents. We can see that this statement is true for
a number of reasons. First, the New Testament was written only 20 to 70 years after the events it records.
Second, the oldest manuscript of the New Testament is a copy of originals that were made about 250
years after these originals were written. It is closer to the time of the original than other ancient manuscripts,
such as those of Aristotle’s Metaphysics, for instance. Third, there are more than 13,000 surviving copies
of various portions of the New Testament, which date from ancient and medieval times. This fact means
that it is highly probable that the original documents are well represented. As far as the Old Testament is
concerned, the recently discovered Dead Sea Scrolls are 700-1000 years closer in time to the original
events than earlier manuscripts we used to rely on and yet their wording is very close to that of these other
manuscripts. This is strong evidence that the text is accurately transmitted. In addition to all of these
reasons, one of the world's outstanding archaeological experts says that archaeology confirms that the
events described in the Old Testament did occur. Thus the Bible is among the most trustworthy of ancient
documents. 

(Based on a leaflet distributed by the Inter-Varsity Christian Fellowship)