YOUR MIND AND HOW TO USE IT/PART 28
CHAPTER XXVIII.
Fallacious Reasoning.
A FALLACY
is defined as "an unsound argument or mode of arguing which, while
appearing to be decisive of a question, is in reality not so; or a fallacious
statement or proposition in which the error is not readily apparent. When a
fallacy is used to deceive others, it is called 'sophistry,'" It is
important that the student should understand the nature of the fallacy and
understand its most common forms. As Jevons says: "In learning how to do
right it is always desirable to be informed as to the ways in which we are
likely to go wrong. In describing to a man the road which he should follow, we
ought to tell him not only the turnings which he is to take but also the
turnings which he is to avoid. Similarly, it is a useful part of logic which
teaches us the ways and turnings by which people most commonly go astray in
reasoning."
In
presenting the following brief statement regarding the more common forms of
fallacy, we omit so far as possible the technical details which belong to
text-books on logic.
Fallacies.
I. True
Collective but False Particular.—An example of this fallacy is found in the
argument that because the French race, collectively, are excitable, therefore a
particular Frenchman must be excitable. Or that because the Jewish race,
collectively, are good business people, therefore the particular Jew must be a
good business man. This is as fallacious as arguing that because a man may
drown in the ocean he should avoid the bath, basin, or cup of water. There is a
vast difference between the whole of a thing and its separate parts. Nitric
acid and glycerin, separately, are not explosive, but, combined, they form
nitro-glycerin, a most dangerous and powerful explosive. Reversing this form of
illustration, we remind you of the old saying: "Salt is a good thing; but
one doesn't want to be put in pickle."
II. Irrelevant
Conclusion.—This fallacy consists in introducing in the conclusion matter
not contained in the premises, or in the confusing of the issue. For instance:
(1) All men are sinful; (2) John Smith is a man; therefore (3) John Smith is a
horse thief. This may sound absurd, but many arguments are as fallacious as
this, and for the same reason. Or another and more subtle form: (1) All thieves
are liars; (2) John Smith is a liar; therefore (3) John Smith is a thief.
The first example arises from the introduction of new matter, and the last from
the confusion of the issue.
III. False
Cause.—This fallacy consists in attributing cause to a thing which is
merely coincident with, or precedent to, the effect. For instance: (1) The cock
crows just before or at the moment of sunrise; therefore (2) the cock-crowing
is the cause of the sunrise. Or, again: (1) Bad crops followed the election of
a Whig president; therefore (2) the Whig party is the cause of the bad crops.
Or, again: (1) Where civilization is the highest, there we find the greatest
number of high hats; therefore (2) high hats are the cause of civilization.
IV. Circular
Reasoning.—In this form of fallacy the person reasoning or arguing
endeavors to explain or prove a thing by itself or its own terms. For instance:
(1) The Whig party is honest because it advocates honest principles; (2) the
Whig principles are honest because they are advocated by an honest party. A
common form of this fallacy in its phase of sophistry is the use of synonyms in
such a manner that they seem to express more than the original conception,
whereas they are really but other terms for the same thing. An historic example
of circular reasoning is the following: (1) The Church of England is the true
Church, because it was established by God; (2) it must have been
established by God, because it is the true Church. This form of sophistry is
most effective when employed in long arguments in which it is difficult to
detect it.
V. Begging
the Question.—This fallacy arises from the use of a false premise, or at least
of a premise the truth of which is not admitted by the opponent. It may be
stated, simply, as "the unwarranted assumption of a premise, generally
the major premise." Many persons in public life argue in this way.
They boldly assert an unwarranted premise, and then proceed to argue logically
from it. The result is confusing to the average person, for, the steps of the
reasoning being logical, it seems as if the argument is sound, the fact of the
unwarranted premise being overlooked. The person using this form of sophistry
proceeds on Aaron Burr's theory of truth being "that which is boldly
asserted and plausibly maintained."
Bulwer
makes one of his characters mention a particularly atrocious form of this
fallacy (although an amusing one) in the following words: "Whenever you
are about to utter something astonishingly false, always begin with: 'It is an
acknowledged fact,' etc. Sir Robert Filmer was a master of this manner of
writing. Thus with what a solemn face that great man attempted to cheat. He
would say: 'It is a truth undeniable that there cannot be any
multitude of men whatsoever, either great or small, etc., but that in the same
multitude there is one man among them that in nature hath a right to be
King of all the rest—as being the next heir of Adam!'"
Look
carefully for the major premise of propositions advanced in argument, spoken or
written. Be sure that the person making the proposition is not "begging
the question" by the unwarranted assumption of the premise.
General
Rule of Inference.
Hyslop
says concerning valid inferences and fallacious ones: "We cannot
infer anything we please from any premises we please. We must
conform to certain definite rules or principles. Any violation of them will be
a fallacy. There are two simple rules which should not be violated: (1) The
subject-matter in the conclusion should be of the same general kind as in the
premises; (2) the facts constituting the premises must be accepted
and must not be fictitious." A close observance of these rules will
result in the detection and avoidance of the principal forms of fallacious
reasoning and sophistry.
Sophistical
Arguments.
There
are a number of tricky practices resorted to by persons in argument, that are
fallacious in intent and result, which we do not consider here in detail
as they scarcely belong to the particular subject of this book. A brief
mention, however, may be permitted in the interest of general information. Here
are the principal ones:—
(1)
Arguing that a proposition is correct because the opponent cannot prove the
contrary. The fallacy is seen when we realize that the statement, "The
moon is made of green cheese," is not proved because we cannot prove the
contrary. No amount of failure to disprove a proposition
really proves it; and no amount of failure to prove a
proposition really disproves it. As a general rule, the burden
of proof rests upon the person stating the proposition, and his opponent is not
called upon to disprove it or else have it considered proved. The old cry of
"You cannot prove that it is not so"
is based upon a fallacious conception.
(2)
Abuse of the opponent, his party, or his cause. This is no real argument or
reasoning. It is akin to proving a point by beating the opponent over the head.
(3)
Arguing that an opponent does not live up to his principles is no argument
against the principles he advocates. A man may advocate the principle of
temperance and yet drink to excess. This simply proves that he preaches better
than he practices; but the truth of the principle of temperance is not affected
in any way thereby. The proof of this is that he may change his practices;
and it cannot be held that the change of his personal habits improves or
changes the nature of the principle.
(4)
Argument of authority is not based on logic. Authority is valuable when really
worthy, and merely as corroboration or adding weight; but it is not logical
argument. The reasons of the authority alone constitute a real
argument. The abuse of this form of argument is shown, in the above reference
to "begging the question," in the quotation from Bulwer.
(5)
Appeal to prejudice or public opinion is not a valid argument, for public
opinion is frequently wrong and prejudice is often unwarranted. And, at the
best, they "have nothing to do with the case" from the standpoint of
logic. The abuse of testimony and claimed evidence is also worthy of
examination, but we cannot go into the subject here.
Fallacies
of Prejudice.
But
perhaps the most dangerous of all fallacies in the search for truth on the part
of the most of us are those which arise from the following:—
(1)
The tendency to reason from what we feel and wish to be true, rather than from
the actual facts of the case, which causes us unconsciously to assume the
mental attitude of "if the facts agree with our likes and pet theories,
all is well; if they do not, so much the worse for the facts."
(2)
The tendency in all of us to perceive only the facts that agree with our
theories and to ignore the others. We find that for which we seek, and overlook
that which does not interest us. Our discoveries follow our interest, and our
interest follows our desires and beliefs.
The
intelligent man or woman realizes these tendencies of human nature and
endeavors to avoid them in his or her own reasoning, but is keenly conscious of
them in the arguments and reasoning of others. A failure to observe and guard
one's self against these tendencies results in bigotry, intolerance,
narrowness, and intellectual astigmatism.
NEXT CHAPTER
Comments
Post a Comment