Intro logic ch 3 doc

3: Informal Fallacies
3.1: Fallacies in General
A fallacy is a defect in an argument that consists in something other than merely false premises. As we
will see, fallacies can be committed in many ways, but usually they involve either a mistake in reasoning
or the creation of some illusion that makes a bad argument appear good (or both). Both deductive and
inductive arguments may contain fallacies; if they do, they are either unsound or uncogent, depending on
the kind of argument. Conversely, if an argument is unsound or uncogent, it has one or more false
premises or it contains a fallacy (or both).
Fallacies are usually divided into two groups: formal and informal. A formal fallacy is one that may be
identified through mere inspection of the form or structure of an argument. Fallacies of this kind are
found only in deductive arguments that have identifiable forms. Chapter 1 presented some of these forms:
categorical syllogisms, disjunctive syllogisms, and hypothetical syllogisms. The following categorical
syllogism contains a formal fallacy:
All bullfights are grotesque rituals/All executions are grotesque rituals//Therefore, all bullfights are executions.
This argument has the following form:
All A are B/All C are B//All A are C.
Through mere inspection of this form, one can see that the argument is invalid. The fact that A, B, and C
stand respectively for ‘‘bullfights,’’ ‘‘grotesque rituals,’’ and ‘‘executions’’ is irrelevant in detecting the
fallacy. The problem may be traced to the second premise. If the letters C and B are interchanged, the
form becomes valid, and the original argument, with the same change introduced, also becomes valid (but
unsound).
Here is an example of a formal fallacy that occurs in a hypothetical syllogism:
If apes are intelligent, then apes can solve puzzles/Apes can solve puzzles//Therefore, apes are intelligent.
This argument has the following form:
If A then B/B//A.
In this case, if A and B are interchanged in the first premise, the form becomes valid, and the original
argument, with the same change, also becomes valid. This fallacy and the one that precedes it will be
discussed in later chapters.
In distinguishing formal from informal fallacies, remember that formal fallacies occur only in deductive
arguments. Thus, if a given argument is inductive, it cannot contain a formal fallacy. Also, keep an eye
out for standard deductive argument forms such as categorical syllogisms and hypothetical syllogisms. If
such an argument is invalid because of an improper arrangement of terms or statements, it commits a
formal fallacy. Section 1.5 investigated some of these forms and gave instruction on distinguishing the
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form from the content of an argument. All of the exercises at the end of that section commit formal
fallacies.
Informal fallacies are those that can be detected only through analysis of the content of the argument.
Consider the following example:
All factories are plants/All plants are things that contain chlorophyll//Therefore, all factories are things that contain chlorophyll.
A cursory inspection of this argument might lead one to think that it has the following form:
All A are B/All B are C//All A are C.
Since this form is valid, one might conclude that the argument itself is valid. Yet the argument is clearly
invalid because it has true premises and a false conclusion. An analysis of the content—that is, the
meaning of the words—reveals the source of the trouble. The word ‘‘plants’’ is used in two different
senses. In the first premise it means a building where something is manufactured, and in the second it
means a life form.
Thus, the argument really has the following invalid form:
All A are B/All C are D//All A are D.
The various informal fallacies accomplish their purpose in so many different ways that no single umbrella
theory covers them all. Some fallacies work by getting the reader or listener to feel various emotions,
such as fear, pity, or camaraderie, and then attaching a certain conclusion to those emotions. Others
attempt to discredit an opposing argument by associating it with certain pejorative features of its author.
And then there are those that appeal to various dispositions on the part of the reader or listener, such as
superstition or mental laziness, to get him or her to accept a conclusion.
By studying the typical ways in which arguers apply these techniques, one is less likely to be fooled by
the fallacious arguments posed by others and is less likely to stumble blindly into fallacies when
constructing arguments for one’s own use.
Since the time of Aristotle, logicians have attempted to classify the various informal fallacies. Aristotle
himself identified thirteen and separated them into two groups. The work of subsequent logicians has
produced dozens more, rendering the task of classifying them even more difficult. The presentation that
follows divides twenty-two informal fallacies into five groups: fallacies of relevance, fallacies of weak
induction, fallacies of presumption, fallacies of ambiguity, and fallacies of grammatical analogy.
3.2: Classification of informal fallacies according Hurley’s Text
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I: Fallacies of Relevance: The fallacies of relevance share the common characteristics that the
arguments in which they occur have premises that are logically irrelevant to the conclusion. Yet the
premises are relevant psychologically, so the conclusion may seem to follow from the premises, even
though it does not follow logically. In a good argument the premises provide genuine evidence in support
of the conclusion. In an argument that commits a fallacy of relevance, on the other hand, the connection
between premises and conclusion is emotional. To identify a fallacy of relevance, therefore, one must be
able to distinguish genuine evidence from various forms of emotional appeal.
1. Appeal to Force (Argumentum ad Baculum: Appeal to the ‘‘Stick’’) - The fallacy of appeal
to force occurs whenever an arguer poses a conclusion to another person and tells that person either
implicitly or explicitly that some harm will come to him or her if he or she does not accept the conclusion.
The fallacy always involves a threat by the arguer to the physical or psychological well-being of the
listener or reader, who may be either a single person or a group of persons. Obviously, such a threat is
logically irrelevant to the subject matter of the conclusion, so any argument based on such a procedure is
fallacious. The ad baculum fallacy often occurs when children argue with one another:
Child to playmate: ‘‘Teletubbies’’ is the best show on TV; and if you don’t believe it, I’m going to call my big brother over here
and he’s going to beat you up.
But it occurs among adults as well:
Secretary to boss: I deserve a raise in salary for the coming year. After all, you know how friendly I am with your wife, and I’m
sure you wouldn’t want her to find out what’s been going on between you and that sexpot client of yours.
The first example involves a physical threat, the second a psychological threat. While neither threat
provides any genuine evidence that the conclusion is true, both provide evidence that someone might be
injured. If the two types of evidence are confused with each other, both arguer and listener may be
deluded into thinking that the conclusion is supported by evidence, when in fact it is not.
The appeal to force fallacy usually accomplishes its purpose by psychologically impeding the reader or
listener from acknowledging a missing premise that, if acknowledged, would be seen to be false or at
least questionable. The two examples just given can be interpreted as concealing the following premises,
both of which are most likely false:
If my brother forces you to admit that ‘‘Teletubbies’’ is the best show on TV, then ‘‘Teletubbies’’ is in fact the best show. If I
succeed in threatening you, then I deserve a raise in salary.
The conclusion of the first argument is that ‘‘Teletubbies’’ is the best show on TV. But just because
someone is forced into saying that it is does not mean that such is the case. Similarly, the conclusion of
the second argument is that the secretary deserves a raise in salary. But if the boss is threatened into
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raising the secretary’s salary, this does not mean that the secretary deserves a raise. Many of the other
informal fallacies can be interpreted as accomplishing their purpose in this way.
2. Appeal to Pity (Argumentum ad Misericordiam) - The appeal to pity fallacy occurs when an
arguer attempts to support a conclusion by merely evoking pity from the reader or listener. This pity may
be directed toward the arguer or toward some third party. Example:
Taxpayer to judge: Your Honor, I admit that I declared thirteen children as dependents on my tax return, even though I have only
two. But if you find me guilty of tax evasion, my reputation will be ruined. I’ll probably lose my job, my poor wife will not be
able to have the operation that she desperately needs, and my kids will starve. Surely I am not guilty.
The conclusion of this argument is ‘‘surely I am not guilty.’’ Obviously, the conclusion is not logically
relevant to the arguer’s set of pathetic circumstances, although it is psychologically relevant. If the arguer
succeeds in evoking pity from the listener or reader, the latter is likely to exercise his or her desire to help
the arguer by accepting the argument. In this way the reader or listener may be fooled into accepting a
conclusion that is not supported by any evidence. The appeal to pity is quite common and is often used by
students on their instructors at exam time and by lawyers on behalf of their clients before judges and
juries.
Of course, some arguments that attempt to evoke sympathetic feelings from the reader or listener are not
fallacious. We might call them arguments from compassion.
Such arguments differ from the fallacious appeal to pity in that, in addition to evoking compassion on
behalf of some person, they supply information about why that person is genuinely deserving of help or
special consideration. Whenever possible these nonfallacious arguments should show that the person in
question is a victim of circumstances and not responsible for the dire straights he finds himself in, that the
recommended help or special consideration is not illegal or inappropriate, and that it will genuinely help
the person in question. In contrast to such arguments, the appeal to pity proceeds by ignoring all of these
considerations and attempts to support a conclusion by merely evoking pity from the reader or listener.
3. Appeal to the People (Argumentum ad Populum) - Nearly everyone wants to be loved,
esteemed, admired, valued, recognized, and accepted by others. The appeal to the people uses these
desires to get the reader or listener to accept a conclusion. Two approaches are involved, one of them
direct, the other indirect.
The direct approach occurs when an arguer, addressing a large group of people, excites the emotions and
enthusiasm of the crowd to win acceptance for his or her conclusion. The objective is to arouse a kind of
mob mentality. This is the strategy used by nearly every propagandist and demagogue. Adolf Hitler was a
master of the technique, but it is also used with some measure of success by speechmakers at Democratic
and Republican national conventions. Waving flags and blaring music add to the overall effect. Because
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the individuals in the audience want to share in the camaraderie, the euphoria, and the excitement, they
find themselves accepting any number of conclusions with ever-increasing fervor.
The direct approach is not limited to oral argumentation, of course; a similar effect can be accomplished
in writing. By using such emotionally charged phraseology as ‘‘fighter of communism,’’ ‘‘champion of
the free enterprise system,’’ and ‘‘defender of the working man,’’ polemicists can awaken the same kind
of mob mentality as they would if they were speaking.
In the indirect approach the arguer aims his or her appeal not at the crowd as a whole but at one or more
individuals separately, focusing on some aspect of their relationship to the crowd. The indirect approach
includes such specific forms as the bandwagon argument, the appeal to vanity, and the appeal to
snobbery. All are standard techniques of the advertising industry.
Here is an example of the bandwagon argument: Of course you want to buy Zest toothpaste. Why, 90 percent of
America brushes with Zest.
The idea is that you will be left behind or left out of the group if you do not use the product.
The appeal to vanity often associates the product with someone who is admired, pursued, or imitated, the
idea being that you, too, will be admired and pursued if you use it. The current television and billboard
ads for the U.S. Marine Corps provide an example. The ads show a strong, handsome man in uniform
holding a gleaming sword, and the caption reads:
The Few, the Proud, the Marines
The message is that if you join the Marines, then you, too, will be admired and respected, just like the
handsome man in the uniform.
The appeal to snobbery depends on a similar kind of association.
A Rolls Royce is not for everyone. If you qualify as one of the select few, this distinguished classic may be seen and driven at
British Motor Cars, Ltd. (By appointment only, please.)
Needless to say, the indirect approach is used by others besides advertisers:
Mother to child: You want to grow up and be just like Wonder Woman, don’t you? Then eat your liver and carrots.
These examples illustrate how the indirect version of the appeal to the people can overlap the false cause
fallacy, which is presented in Section 3.3. Thus, the previous example might be interpreted to suggest that
eating liver and carrots will cause one to become just like Wonder Woman. If so, the fallacy could be
identified as false cause.
Both the direct and indirect approaches of the ad populum fallacy have the same basic structure:
You want to be accepted/included-in-the-group/loved/esteemed. . . . Therefore, you should accept XYZ as true.
In the direct approach the arousal of a mob mentality produces an immediate feeling of belonging for
each person in the crowd. Each person feels united with the crowd, which evokes a sense of strength and
security. When the crowd roars its approval of the conclusions that are then offered, anyone who does not
accept them automatically cuts himself or herself off from the crowd and risks the loss of his or her
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security, strength, and acceptance. The same thing happens in the indirect approach, but the context and
technique are somewhat subtler.
4. Argument Against the Person (Argumentum ad Hominem) - This fallacy always involves two
arguers. One of them advances (either directly or implicitly) a certain argument and the other then
responds by directing his or her attention not to the first person’s argument but to the first person himself.
When this occurs, the second person is said to commit an argument against the person.
The argument against the person occurs in three forms: the ad hominem abusive, the ad hominem
circumstantial, and the tu quoque. In the ad hominem abusive, the second person responds to the first
person’s argument by verbally abusing the first person.
Example: Before he died, poet Allen Ginsberg argued in favor of legalizing pornography. But Ginsberg’s arguments are
nothing but trash. Ginsberg was a marijuana-smoking homosexual and a thoroughgoing advocate of the drug culture.
Because Ginsberg’s being a marijuana-smoking homosexual and advocate of the drug culture is irrelevant
to whether the premises of his argument support the conclusion, this argument is fallacious.
Not all cases of the ad hominem abusive are as blunt as this one, but they are just as fallacious. Example:
William Buckley has argued in favor of legalizing drugs such as cocaine and heroin.
But Buckley is just another one of those upper-crust intellectuals who is out of touch with real America. No sensible person
should listen to his pseudosolutions.
Again, whether Buckley is an upper-crust intellectual has nothing to do with whether his premises support
his conclusion.
The ad hominem circumstantial begins the same way as the ad hominem abusive, but instead of heaping
verbal abuse on his or her opponent, the respondent attempts to discredit the opponent’s argument by
alluding to certain circumstances that affect the opponent. By doing so the respondent hopes to show that
the opponent is predisposed to argue the way he or she does and should therefore not be taken seriously.
Here is an example:
The Dalai Lama argues that China has no business in Tibet and that the West should do something about it. But the Dalai Lama
just wants the Chinese to leave so he can return as leader. Naturally he argues this way. Therefore, we should reject his
arguments.
The author of this argument ignores the substance of the Dalai Lama’s argument and attempts to discredit
it by calling attention to certain circumstances that affect the Dalai Lama—namely, that he wants to return
to Tibet as its leader. But the fact that the Dalai Lama happens to be affected by these circumstances is
irrelevant to whether his premises support a conclusion. The ad hominem circumstantial is easy to
recognize because it always takes this form: ‘‘Of course Mr. X argues this way; just look at the
circumstances that affect him.’’
The tu quoque (‘‘you too’’) fallacy begins the same way as the other two varieties of the ad hominem
argument, except that the second arguer attempts to make the first appear to be hypocritical or arguing in
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bad faith. The second arguer usually accomplishes this by citing features in the life or behavior of the first
arguer that conflict with the latter’s conclusion. In effect, the second arguer says, ‘‘How dare you argue
that I should stop doing X; why, you do (or have done) X yourself.’’
Example: Child to parent: Your argument that I should stop stealing candy from the corner store is no good. You told me
yourself just a week ago that you, too, stole candy when you were a kid.
Obviously, whether the parent stole candy is irrelevant to whether the parent’s premises support the
conclusion that the child should not steal candy.
It is important to keep in mind that the purpose of an ad hominem argument is to discredit another
person’s argument by placing its author in a bad light. Thus, for the fallacy to be committed there must
always be two arguers (at least implicitly). If it should turn out that the person being attacked is not an
arguer, then the personal comments made by the attacker may well be relevant to the conclusion that is
drawn.
In general, personal observations are relevant to conclusions about what kind of person someone is (good,
bad, stingy, trustworthy, and so forth) and whether a person has done something.
Example: International terrorist Osama bin Laden planned the bombing of the U.S. embassies in Kenya and Tanzania, killing
over two hundred innocent people, and he supports terrorist causes all over the world. Bin Laden is therefore a wicked and
irresponsible person.
The conclusion is not that Bin Laden’s argument is bad but that Bin Laden himself is bad. Because the
premises give relevant support to this conclusion, the argument commits no fallacy. Another example:
Shakespeare cannot possibly have written the thirty-six plays attributed to him, because the real Shakespeare was a two-bit
country businessman who barely finished the fourth grade in school and who never left the confines of his native England.
The conclusion is not that some argument of Shakespeare’s is bad but that Shakespeare did not write
certain plays. Again, since the premises are relevant to this conclusion, the argument commits no ad
hominem fallacy.
Determining what kind of person someone is includes determining whether that person is trustworthy.
Thus personal comments are often relevant in evaluating whether a person’s proclamations or statements,
unsupported by evidence, warrant our belief. Examples of such statements include promises to do
something, testimony given by a witness, and testimonials in support of a product or service. Here is an
example of an argument that discredits a witness:
Mickey has testified that he saw Freddy set fire to the building. But Mickey was recently convicted on ten counts of perjury, and
he hates Freddy with a passion and would love to see him sent to jail. Therefore, you should not believe Mickey’s testimony.
This argument commits no fallacy. The conclusion is not that you should reject Mickey’s argument but
rather that you should reject his testimony. Testimony is not argument, and the fact that the witness is a
known liar and has a motive to lie now is relevant to whether we should believe him. Furthermore, note
that the conclusion is not that Mickey’s statement is literally false but rather that we should not believe
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the statement. It is quite possible that Mickey really did see Freddy set fire to the building and that
Mickey’s statement to that effect is true. But if our only reason for believing this statement is the mere
fact that Mickey has made it, then given the circumstances, we are not justified in that belief. Personal
factors are never relevant to truth and falsity as such, but they are relevant to believability.
Yet there is often a close connection between truth and believability, and this provides one of the reasons
why ad hominem arguments are often effective. In evaluating any argument there are always two issues to
be considered: the quality of the reasoning and the truth of the premises. As we have noted, both are
irrelevant to the personal characteristics of the arguer. But whether we accept the premises as true may
depend on the credibility of the arguer. Knowing that the arguer is biased or has a motive to lie may
provide good grounds for distrusting the premises. Another reason why ad hominem arguments are
effective is that they engage the emotions of readers and listeners and thereby motivate them to transfer
their negative feelings about the arguer onto the argument.
5. Accident: The fallacy of accident is committed when a general rule is applied to a specific case it
was not intended to cover. Typically, the general rule is cited (either directly or implicitly) in the premises
and then wrongly applied to the specific case mentioned in the conclusion. Two examples:
Freedom of speech is a constitutionally guaranteed right. Therefore, John Q. Radical should not be arrested for his speech that
incited the riot last week. Property should be returned to its rightful owner. That drunken sailor who is starting a fight with his
opponents at the pool table lent you his .45-caliber pistol, and now he wants it back. Therefore, you should return it to him now.
In the first example, the general rule is that freedom of speech is normally guaranteed, and the specific
case is the speech made by John Q. Radical. Because the speech incited a riot, the rule does not apply. In
the second example, the general rule is that property should be returned to its rightful owner, and the
specific case is the sailor who wants his gun returned. The rule does not apply because the return of the
property might result in serious injury or death.
The fallacy of accident gets its name from the fact that the specific case exhibits some attribute, or
‘‘accident,’’ that prevents the general rule from applying. In the first example the accident is that the
speech incited a riot; in the second example, the accidents are that the sailor is drunk, that he is starting a
fight, and that the property in question is dangerous.
6. Straw Man: The straw man fallacy is committed when an arguer distorts an opponent’s argument
for the purpose of more easily attacking it, demolishes the distorted argument, and then concludes that the
opponent’s real argument has been demolished. By so doing, the arguer is said to have set up a straw man
and knocked it down, only to conclude that the real man (opposing argument) has been knocked down as
well.
Example: Mr. Goldberg has argued against prayer in the public schools. Obviously Mr. Goldberg advocates atheism. But
atheism is what they used to have in Russia. Atheism leads to the suppression of all religions and the replacement of God by an
omnipotent state. Is that what we want for this country? I hardly think so. Clearly Mr. Goldberg’s argument is nonsense.
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Like the argument against the person fallacy, the straw man fallacy involves two arguers. Mr. Goldberg,
who is the first arguer, has presented an argument against prayer in the public schools. The second arguer
then attacks Goldberg’s argument by equating it with an argument for atheism. He then attacks atheism
and concludes that Goldberg’s argument is nonsense. Since Goldberg’s argument had nothing to do with
atheism, the second argument commits the straw man fallacy.
As this example illustrates, the kind of distortion the second arguer resorts to is often an attempt to
exaggerate the first person’s argument or make it look more extreme than it really is. Here are two more
examples: The garment workers have signed a petition arguing for better ventilation on the work premises. Unfortunately, air
conditioning is expensive. Air ducts would have to be run throughout the factory, and a massive heat exchange unit installed on
the roof. Also, the cost of operating such a system during the summer would be astronomical. In view of these considerations the
petition must be rejected.
The student status committee has presented us with an argument favoring alcohol privileges on campus. What do the students
want? Is it their intention to stay boozed up from the day they enter as freshmen till the day they graduate? Do they expect us to
open a bar for them? Or maybe a chain of bars all over campus? Such a proposal is ridiculous!
In the first argument, the petition is merely for better ventilation in the factory—maybe a fan in the
window during the summer. The arguer exaggerates this request to mean an elaborate air conditioning
system installed throughout the building. He then points out that this is too expensive and concludes by
rejecting the petition. A similar strategy is used in the second argument. The arguer distorts the request
for alcohol privileges to mean a chain of bars all over campus. Such an idea is so patently outlandish that
no further argument is necessary.
7. Missing the Point (Ignoratio Elenchi) - All the fallacies we have discussed thus far have been
instances of cases where the premises of an argument are irrelevant to the conclusion. Missing the point
illustrates a special form of irrelevance. This fallacy occurs when the premises of an argument support
one particular conclusion, but then a different conclusion, often vaguely related to the correct conclusion,
is drawn. Whenever one suspects that such a fallacy is being committed, he or she should be able to
identify the correct conclusion, the conclusion that the premises logically imply. This conclusion must be
significantly different from the conclusion that is actually drawn.
Examples: Crimes of theft and robbery have been increasing at an alarming rate lately. The conclusion is obvious: we must
reinstate the death penalty immediately. Abuse of the welfare system is rampant nowadays. Our only alternative is to abolish the
system altogether.
At least two correct conclusions are implied by the premise of the first argument: either ‘‘we should
provide increased police protection in vulnerable neighborhoods’’ or ‘‘we should initiate programs to
eliminate the causes of the crimes.’’ Reinstating the death penalty is not a logical conclusion at all.
Among other things, theft and robbery are not capital crimes. In the second argument the premises
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logically suggest some systematic effort to eliminate the cheaters rather than eliminating the system
altogether.
Ignoratio elenchi means ‘‘ignorance of the proof.’’ The arguer is ignorant of the logical implications of
his or her own premises and, as a result, draws a conclusion that misses the point entirely. The fallacy has
a distinct structure all its own, but in some ways it serves as a catchall for arguments that are not clear
instances of one or more of the other fallacies. An argument should not be identified as a case of missing
the point, however, if one of the other fallacies fits.
8. Red Herring: This fallacy is closely associated with missing the point (ignoratio elenchi). The red
herring fallacy is committed when the arguer diverts the attention of the reader or listener by changing the
subject to a different but sometimes subtly related one. He or she then finishes by either drawing a
conclusion about this different issue or by merely presuming that some conclusion has been established.
By so doing, the arguer purports to have won the argument. The fallacy gets its name from a procedure
used to train hunting dogs to follow a scent. A red herring (or bag of them) is dragged across the trail with
the aim of leading the dogs astray. Since red herrings have an especially potent scent (caused in part by
the smoking process used to preserve them), only the best dogs will follow the original scent.
To use the red herring fallacy effectively, the arguer must change the original subject of the argument
without the reader or listener noticing it. One way of doing this is to change the subject to one that is
subtly related to the original subject.
Here are two examples of this technique: Environmentalists are continually harping about the dangers of nuclear power.
Unfortunately, electricity is dangerous no matter where it comes from. Every year hundreds of people are electrocuted by
accident. Since most of these accidents are caused by carelessness, they could be avoided if people would just exercise greater
caution.
There is a good deal of talk these days about the need to eliminate pesticides from our fruits and vegetables. But many of these
foods are essential to our health. Carrots are an excellent source of vitamin A, broccoli is rich in iron, and oranges and grapefruits
have lots of vitamin C.
Both arguments commit the red herring fallacy. In the first, the original issue is whether nuclear power is
dangerous. The arguer changes this subject to the danger of electrocution and proceeds to draw a
conclusion about that. The new subject is clearly different from the possibility of nuclear explosion or
meltdown, but the fact that both are related to electricity facilitates the arguer’s goal of leading someone
off the track.
In the second argument, the original issue is pesticides, and the arguer changes it to the value of fruits and
vegetables in one’s diet. Again, the fact that the second topic is related to the first assists the arguer in
committing the fallacy. In neither case does the arguer draw a conclusion about the original topic, but by
merely diverting the attention of the reader or listener, the arguer creates the presumption of having won
the argument.
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A second way of using the red herring effectively is to change the subject to some flashy, eye-catching
topic that is virtually guaranteed to distract the listener’s attention.
Topics of this sort include sex, crime, scandal, immorality, death, and any other topic that might serve as
the subject of gossip. Here is an example of this technique:
Professor Conway complains of inadequate parking on our campus. But did you know that last year Conway carried on a torrid
love affair with a member of the English Department? The two used to meet every day for clandestine sex in the copier room.
Apparently they didn’t realize how much you can see through that fogged glass window. Even the students got an eyeful. Enough
said about Conway.
The red herring fallacy can be confused with the straw man fallacy because both have the effect of
drawing the reader/listener off the track. This confusion can usually be avoided by remembering the
unique ways in which they accomplish this purpose.
In the straw man, the arguer begins by distorting an opponent’s argument and concludes by knocking
down the distorted argument. In the red herring, on the other hand, the arguer ignores the opponent’s
argument (if there is one) and subtly changes the subject. Thus, to distinguish the two fallacies, one
should attempt to determine whether the arguer has knocked down a distorted argument or simply
changed the subject. Also keep in mind that straw man always involves two arguers, at least implicitly,
whereas a red herring often does not.
Both the red herring and straw man fallacies are susceptible of being confused with missing the point,
because all three involve a similar kind of irrelevancy. To avoid this confusion, one should note that both
red herring and straw man proceed by generating a new set of premises, whereas missing the point does
not. Straw man draws a conclusion from new premises that are obtained by distorting an earlier argument,
and red herring, if it draws any conclusion at all, draws one from new premises obtained by changing the
subject. Missing the point, however, draws a conclusion from the original premises. Also, in the red
herring and straw man, the conclusion, if there is one, is relevant to the premises from which it is drawn;
but in missing the point, the conclusion is irrelevant to the premises from which it is drawn. Finally,
remember that missing the point serves in part as a kind of catchall fallacy, and a fallacious argument
should not be identified as a case of missing the point if one of the other fallacies clearly fits.
II. Fallacies of Weak Induction - The fallacies of weak induction occur not because the
premises are logically irrelevant to the conclusion, as is the case with the eight fallacies of relevance, but
because the connection between premises and conclusion is not strong enough to support the conclusion.
In each of the following fallacies, the premises provide at least a shred of evidence in support of the
conclusion, but the evidence is not nearly good enough to cause a reasonable person to believe the
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conclusion. Like the fallacies of relevance, however, the fallacies of weak induction often involve
emotional grounds for believing the conclusion.
9. Appeal to Unqualified Authority (Argumentum ad Verecundiam) - We saw in Chapter 1 that
an argument from authority is an inductive argument in which an arguer cites the authority or testimony
of another person in support of some conclusion. The appeal to unqualified authority fallacy is a variety
of the argument from authority and occurs when the cited authority or witness is not trustworthy. There
are several reasons why an authority or witness might not be trustworthy. The person might lack the
requisite expertise, might be biased or prejudiced, might have a motive to lie or disseminate
‘‘misinformation,’’ or might lack the requisite ability to perceive or recall. The following illustrate these
reasons: Dr. Bradshaw, our family physician, has stated that the creation of muonic atoms of deuterium and tritium hold the key
to producing a sustained nuclear fusion reaction at room temperature. In view of Dr. Bradshaw’s expertise as a physician, we
must conclude that this is indeed true.
This conclusion deals with nuclear physics, and the authority is a family physician.
Because it is unlikely that a physician would be an expert in nuclear physics, the argument commits an
appeal to unqualified authority.
David Duke, former Grand Wizard of the Ku Klux Klan, has stated, ‘‘Jews are not good Americans. They have no understanding
of what America is.’’ On the basis of Duke’s authority, we must therefore conclude that the Jews in this country are un-
American.
As an authority, David Duke is clearly biased, so his statements cannot be trusted.
James W. Johnston, Chairman of R. J. Reynolds Tobacco Company, testified before Congress that tobacco is not an addictive
substance and that smoking cigarettes does not produce any addiction. Therefore, we should believe him and conclude that
smoking does not in fact lead to any addiction.
If Mr. Johnston had admitted that tobacco is addictive, it would have opened the door to government
regulation, which could put his company out of business. Thus, because Johnston had a clear motive to
lie, we should not believe his statements.
Old Mrs. Furguson (who is practically blind) has testified that she saw the defendant stab the victim with a bayonet while she was
standing in the twilight shadows 100 yards from the incident. Therefore, members of the jury, you must find the defendant guilty.
Here the witness lacks the ability to perceive what she has testified to, so her testimony is untrustworthy.
In deciding whether a person is a qualified authority, one should keep two important points in mind. First,
the person might be an authority in more than one field. For example, a chemist might also be an
authority in biology, or an economist might also be an authority in law. The second point is that there are
some areas in which practically no one can be considered an authority. Such areas include politics,
morals, and religion. For example, if someone were to argue that abortion is immoral because a certain
philosopher or religious leader has said so, the argument would be weak regardless of the authority’s
qualifications. Many questions in these areas are so hotly contested that there is no conventional wisdom
an authority can depend on.
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10. Appeal to Ignorance (Argumentum ad Ignorantiam) - When the premises of an argument state
that nothing has been proved one way or the other about something, and the conclusion then makes a
definite assertion about that thing, the argument commits an appeal to ignorance. The issue usually
involves something that is incapable of being proved or something that has not yet been proved. Example:
People have been trying for centuries to provide conclusive evidence for the claims of astrology, and no one has ever succeeded.
Therefore, we must conclude that astrology is a lot of nonsense.
Conversely, the following argument commits the same fallacy.
People have been trying for centuries to disprove the claims of astrology, and no one has ever succeeded. Therefore, we must
conclude that the claims of astrology are true.
The premises of an argument are supposed to provide positive evidence for the conclusion. The premises
of these arguments, however, tell us nothing about astrology; rather, they tell us about what certain
unnamed and unidentified people have tried unsuccessfully to do. This evidence may provide some slight
reason for believing the conclusion, but certainly not sufficient reason.
These examples do, however, lead us to the first of two important exceptions to the appeal to ignorance.
The first stems from the fact that if qualified researchers investigate a certain phenomenon within their
range of expertise and fail to turn up any evidence that the phenomenon exists, this fruitless search by
itself constitutes positive evidence about the question. Consider, for example, the following argument:
Teams of scientists attempted over a number of decades to detect the existence of the luminiferous aether, and all failed to do so.
Therefore, the luminiferous aether does not exist.
The premises of this argument are true. Given the circumstances, it is likely that the scientists in question
would have detected the aether if in fact it did exist. Since they did not detect it, it probably does not
exist. Thus, we can say that the above argument is inductively strong (but not deductively valid).
As for the two arguments about astrology, if the attempts to prove or disprove the astrological claims had
been done in a systematic way by qualified experts, it is more likely that the arguments would be good.
Exactly what is required to qualify someone to investigate astrological claims is, of course, difficult to
say. But as these arguments stand, the premises state nothing about the qualifications of the investigators,
and so the arguments remain fallacious.
It is not always necessary, however, that the investigators have special qualifications.
The kinds of qualifications needed depend on the situation. Sometimes the mere ability to see and report
what one sees is sufficient.
Example: No one has ever seen Mr. Andrews drink a glass of wine, beer, or any other alcoholic beverage. Probably Mr.
Andrews is a nondrinker.
Because it is highly probable that if Mr. Andrews were a drinker, somebody would have seen him
drinking, this argument is inductively strong. No special qualifications are needed to be able to see
someone take a drink.
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The second exception to the appeal to ignorance relates to courtroom procedure.
In the United States and Canada, among other countries, a person is presumed innocent until proven
guilty. If the prosecutor in a criminal trial fails to prove the guilt of the defendant beyond reasonable
doubt, counsel for the defense may justifiably argue that his or her client is not guilty.
Example: Members of the jury, you have heard the prosecution present its case against the defendant. Nothing, however, has
been proved beyond a reasonable doubt. Therefore, under the law, the defendant is not guilty.
This argument commits no fallacy because ‘‘not guilty’’ means, in the legal sense, that guilt beyond a
reasonable doubt has not been proved. The defendant may indeed have committed the crime of which he
or she is accused, but if the prosecutor fails to prove guilt beyond a reasonable doubt, the defendant is
considered ‘‘not guilty.’’
11. Hasty Generalization (Converse Accident) - Hasty generalization is a fallacy that affects
inductive generalizations. In Chapter 1 we saw that an inductive generalization is an argument that draws
a conclusion about all members of a group from evidence that pertains to a selected sample. The fallacy
occurs when there is a reasonable likelihood that the sample is not representative of the group. Such
likelihood may arise if the sample is either too small or not randomly selected.
Here are two examples: After only one year the alternator went out in Mr. O’Grady’s new Chevrolet. Mrs. Dodson’s
Oldsmobile developed a transmission problem after six months. The obvious conclusion is that cars made by General Motors are
just a pile of junk these days.
Six Arab fundamentalists were convicted of bombing the World Trade Center in New York City. The message is clear: Arabs are
nothing but a pack of religious fanatics prone to violence.
In these arguments a conclusion about a whole group is drawn from premises that mention only two
instances. Because such small, atypical samples are not sufficient to support a general conclusion, each
argument commits a hasty generalization. The second example indicates how hasty generalization plays a
role in racial (and religious) prejudice.
The mere fact that a sample may be small, however, does not necessarily mean that it is atypical. On the
other hand, the mere fact that a sample may be large does not guarantee that it is typical. In the case of
small samples, various factors may intervene that render such a sample typical of the larger group.
Examples: Ten milligrams of substance Z was fed to four mice and within two minutes all four went into shock and died.
Probably substance Z, in this amount, is fatal to the average mouse.
On three separate occasions I drank a bottle of Figowitz beer and found it flat and bitter. Probably I would find every bottle of
Figowitz beer flat and bitter.
Neither of these arguments commits the fallacy of hasty generalization because in neither case is there
any likelihood that the sample is atypical of the group. In the first argument the fact that the mice died in
only two minutes suggests the existence of a causal connection between eating substance Z and death. If
there is such a connection, it would hold for other mice as well. In the second example the fact that the
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taste of beer typically remains constant from bottle to bottle causes the argument to be strong, even
though only three bottles were sampled.
In the case of large samples, if the sample is not random, it may not be typical of the larger group.
Example: One hundred thousand voters from Orange County, California, were surveyed on their choice for governor, and 68
percent said they intend to vote for the Republican candidate. Clearly the Republican candidate will be elected.
Even though the sample cited in this argument is large, the argument commits a hasty generalization. The
problem is that Orange County is overwhelmingly Republican, so the mere fact that 68 percent intend to
vote for the Republican candidate is no indication of how others in the state intend to vote. In other
words, the survey was not conducted randomly, and for this reason the argument is fatally flawed. The
need for randomness in samples is discussed further in Section 9.4 of this book.
Hasty generalization is otherwise called ‘‘converse accident’’ because it proceeds in a direction opposite
to that of accident. Whereas accident proceeds from the general to the particular, converse accident moves
from the particular to the general. The premises cite some characteristic affecting one or more atypical
instances of a certain class, and the conclusion then applies that characteristic to all members of the class.
12. False Cause: The fallacy of false cause occurs whenever the link between premises and conclusion
depends on some imagined causal connection that probably does not exist. Whenever an argument is
suspected of committing the false cause fallacy, the reader or listener should be able to say that the
conclusion depends on the supposition that X causes Y, whereas X probably does not cause Y at all.
Examples: During the past two months, every time that the cheerleaders have worn blue ribbons in their hair, the basketball
team has been defeated. Therefore, to prevent defeats in the future, the cheerleaders should get rid of those blue ribbons.
Successful business executives are paid salaries in excess of $50,000. Therefore, the best way to ensure that Ferguson will
become a successful executive is to raise his salary to at least $50,000. There are more laws on the books today than ever before,
and more crimes are being committed than ever before. Therefore, to reduce crime we must eliminate the laws.
The first argument depends on the supposition that the blue ribbons caused the defeats, the second on the
supposition that a high salary causes success, and the third on the supposition that laws cause crime. In no
case is it likely that any causal connection exists.
The first argument illustrates a variety of the false cause fallacy called post hoc ergo propter hoc (‘‘after
this, therefore on account of this’’). This variety of the fallacy presupposes that just because one event
precedes another event the first event causes the second. Obviously, mere temporal succession is not
sufficient to establish a causal connection. Nevertheless, this kind of reasoning is quite common and lies
behind most forms of superstition. (Example: ‘‘A black cat crossed my path and later I tripped and
sprained my ankle. It must be that black cats really are bad luck.’’) The second and third arguments
illustrate a variety of the false cause fallacy called non causa pro causa (‘‘not the cause for the cause’’).
This variety is committed when what is taken to be the cause of something is not really the cause at all
and the mistake is based on something other than mere temporal succession. In reference to the second
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argument, success as an executive causes increases in salary—not the other way around—so the argument
mistakes the cause for the effect. In reference to the third argument, the increase in crime is, for the most
part, only coincidental with the increase in the number of laws. Obviously, the mere fact that one event is
coincidental with another is not sufficient reason to think that one caused the other.
A third variety of the false cause fallacy, and one that is probably committed more often than either of the
others in their pure form, is oversimplified cause. This variety occurs when a multitude of causes is
responsible for a certain effect but the arguer selects just one of these causes and represents it as if it were
the sole cause.
Here are some examples: The quality of education in our grade schools and high schools has been declining for years.
Clearly, our teachers just aren’t doing their job these days. Today, all of us can look forward to a longer life span than our parents
and grandparents. Obviously, we owe our thanks to the millions of dedicated doctors who expend every effort to ensure our
health.
In the first argument, the decline in the quality of education is caused by many factors, including lack of
discipline in the home, parental uninvolvement, too much television, and drug use by students. Poor
teacher performance is only one of these factors and probably a minor one at that. In the second
argument, the efforts of doctors are only one among many factors responsible for our longer life span.
Other, more important factors include a better diet, more exercise, reduced smoking, safer highways, and
more stringent occupational safety standards.
The oversimplified cause fallacy is usually motivated by self-serving interests. Sometimes the arguer
wants to take undeserved credit for himself or give undeserved credit to some movement with which he or
she is affiliated. At other times, the arguer wants to heap blame on an opponent or shift blame from
himself or herself onto some convenient occurrence. Instances of the fallacy can resemble either the post
hoc or the non causa pro causa varieties in that the alleged cause can occur either prior to or concurrently
with the effect. It differs from the other varieties of false cause fallacy in that the single factor selected for
credit or blame is often partly responsible for the effect, but responsible to only a minor degree.
The false cause fallacy is often convincing because it is often difficult to determine whether two
phenomena are causally related. A lengthy time lapse between the operation of the cause and the
occurrence of the effect can exacerbate the problem. For example, the thirty-year interval between
exposure to asbestos and the onset of asbestosis impeded the recognition of a causal connection. Also,
when two events are causally related, it may be hard to determine the degree of relatedness. Thus, there
may be some connection between the electromagnetic field produced by high voltage transmission lines
and leukemia, but the connection may be extremely slight. Finally, when a causal connection is
recognized, it may be difficult to determine which is the cause and which is the effect. For example, an
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allergic reaction may be connected with an episode of anxiety, but it may be hard to tell if the allergy
causes the anxiety or if the anxiety causes the allergy.
The realm of human action constitutes another area in which causal connections are notoriously difficult
to establish. For example, the attorneys for accused murderer Dan White argued that Twinkies, Coke, and
potato chips caused him to kill San Francisco Mayor George Moscone. Other attorneys have blamed their
clients’ crimes on PMS, rap music, childhood abuse, mental retardation, and hallucinations. The complex
nature of human motivation renders all such causal claims difficult to evaluate.
The situation may become even worse when whole nations of people are involved. Thus, the recent drop
in crime rates has been attributed to ‘‘three strikes’’ laws, but it is difficult to say whether this or some
other factor is really responsible.
One point that should be kept in mind when establishing causal connections is that statistical correlations
by themselves often reveal little about what is actually going on. For example, if all that we knew about
smoking and lung cancer was that the two frequently occur together, we might conclude any number of
things. We might conclude that both have a common cause, such as a genetic predisposition, or we might
conclude that lung cancer is a disease contracted early in life and that it manifests itself in its early stages
by a strong desire for tobacco. Fortunately, in the case of smoking and lung cancer there is more evidence
than a mere statistical correlation. This additional evidence inclines us to believe that the smoking is a
cause of the cancer.
The fallacy of slippery slope is a variety of the false cause fallacy. It occurs when the conclusion of
an argument rests upon an alleged chain reaction and there is not sufficient reason to think that the chain
reaction will actually take place. Here is an example:
Immediate steps should be taken to outlaw pornography once and for all. The continued manufacture and sale of pornographic
material will almost certainly lead to an increase in sex-related crimes such as rape and incest. This in turn will gradually erode
the moral fabric of society and result in an increase in crimes of all sorts. Eventually a complete disintegration of law and order
will occur, leading in the end to the total collapse of civilization.
Because there is no good reason to think that the mere failure to outlaw pornography will result in all
these dire consequences, this argument is fallacious. An equally fallacious counterargument is as follows:
Attempts to outlaw pornography threaten basic civil rights and should be summarily abandoned. If pornography is outlawed,
censorship of newspapers and
Weak analogy: news magazines is only a short step away. After that there will be censorship of textbooks, political speeches, and
the content of lectures delivered by university professors. Complete mind control by the central government will be the inevitable
result.
Both arguments attempt to persuade the reader or listener that the welfare of society rests on a ‘‘slippery
slope’’ and that a single step in the wrong direction will result in an inevitable slide all the way to the
bottom.
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Deciding whether a slippery slope fallacy has been committed can be difficult when there is uncertainty
whether the alleged chain reaction will or will not occur. This question is discussed in Section 3.5. But
many slippery slopes rest on amere emotional conviction on the part of the arguer that a certain action or
policy is bad and the arguer attempts to trump up support for his or her position by citing all sorts of dire
consequences that will result if the action is taken or the policy followed. In such cases there is usually
little problem in identifying the argument as a slippery slope.
14. Weak Analogy: This fallacy affects inductive arguments from analogy. As we saw in Chapter 1, an
argument from analogy is an argument in which the conclusion depends on the existence of an analogy,
or similarity, between two things or situations. The fallacy of weak analogy is committed when the
analogy is not strong enough to support the conclusion that is drawn.
Example: Harper’s new car is bright blue, has leather upholstery, and gets excellent gas mileage. Crowley’s new car is also
bright blue and has leather upholstery. Therefore, it probably gets excellent gas mileage, too.
Because the color of a car and the choice of upholstery have nothing to do with gasoline consumption,
this argument is fallacious.
Evaluating an argument having this form requires a two-step procedure: (1) Identify the attributes a, b, c, .
. . that the two entities A and B share in common, and (2) determine how the attribute z, mentioned in the
conclusion, relates to the attributes a, b, c, . . . If some causal or systematic relation exists between z and
a, b, or c, the argument is strong; otherwise it is weak. In the argument above, the two entities share the
attributes of being cars; the attributes entailed by being a car, such as having four wheels; and the
attributes of color and upholstery material. Because none of these attributes is systematically or causally
related to good gas mileage, the argument is fallacious.
As an illustration of when the requisite systematic or causal relation does and does not exist, consider the
following arguments:
The flow of electricity through a wire is similar to the flow of water through a pipe. Obviously a large-diameter pipe will carry a
greater flow of water than a pipe of small diameter. Therefore, a large-diameter wire should carry a greater flow of electricity
than a small-diameter wire.
The flow of electricity through a wire is similar to the flow of water through a pipe. When water runs downhill through a pipe,
the pressure at the bottom of the hill is greater than it is at the top. Thus, when electricity flows downhill through
a wire, the voltage should be greater at the bottom of the hill than at the top.
The first argument is good and the second is fallacious. Both arguments depend on the similarity between
water molecules flowing through a pipe and electrons flowing through a wire. In both cases there is a
systematic relation between the diameter of the pipe/wire and the amount of flow. In the first argument
this systematic relation provides a strong link between premises and conclusion, and so the argument is a
good one. But in the second argument a causal connection exists between difference in elevation and
increase in pressure that holds for water but not for electricity. Water molecules flowing through a pipe
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are affected by gravity, but electrons flowing through a wire are not. Thus, the second argument is
fallacious.
The theory and evaluation of arguments from analogy is one of the most complex and elusive subjects in
all of logic.
3.4 Fallacies of Presumption, Ambiguity, and Grammatical Analogy
The fallacies of presumption include begging the question, complex question, false dichotomy, and
suppressed evidence. These fallacies arise not because the premises are irrelevant to the conclusion or
provide insufficient reason for believing the conclusion but because the premises presume what they
purport to prove. Begging the question presumes that the premises provide adequate support for the
conclusion when in fact they do not, and complex question presumes that a question can be answered by a
simple ‘‘yes,’’ ‘‘no,’’ or other brief answer when a more sophisticated answer is needed. False dichotomy
presumes that an ‘‘either . . . or . . .’’ statement presents mutually exhaustive alternatives when in fact it
does not, and suppressed evidence presumes that no important evidence has been overlooked by the
premises when in fact it has.
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The fallacies of ambiguity include equivocation and amphiboly. These fallacies arise from the
occurrence of some form of ambiguity in either the premises or the conclusion (or both). As we saw in
Section 2.1, an expression is ambiguous if it is susceptible to different interpretations in a given context.
The words ‘‘light’’ and ‘‘bank’’ are ambiguous, as is the statement ‘‘Tuna are biting off the Washington
coast.’’
When the conclusion of an argument depends on a shift in meaning of an ambiguous word or phrase or on
the wrong interpretation of an ambiguous statement, the argument commits a fallacy of ambiguity.
The fallacies of grammatical analogy include composition and division. Arguments that commit these
fallacies are grammatically analogous to other arguments that are good in every respect. Because of this
similarity in linguistic structure, such fallacious arguments may appear good yet be bad.
15. Begging the Question (Petitio Principii) - The fallacy of begging the question is committed
whenever the arguer creates the illusion that inadequate premises provide adequate support for the
conclusion by leaving out a key premise, by restating the conclusion as a premise, or by reasoning in a
circle. The latin name for this fallacy, petitio principii, means ‘‘request for the source.’’ The actual source
of support for the conclusion is not apparent, and so the argument is said to beg the question. After
reading or hearing the argument, the observer is inclined to ask, ‘‘But how do you know X?’’ where X is
the needed support.
The first, and most common, way of committing this fallacy is by leaving a key premise out of the
argument while creating the illusion that nothing more is needed to establish the conclusion. Examples:
Murder is morally wrong. This being the case, it follows that abortion is morally wrong. Of course humans and apes evolved
from common ancestors. Just look how similar they are.
It’s obvious that the poor in this country should be given handouts from the government. After all, these people earn less than the
average citizen. Clearly, terminally ill patients have a right to doctor assisted suicide. After all, many
of these people are unable to commit suicide by themselves.
The first of these arguments begs the question ‘‘How do you know that abortion is a form of murder?’’
The second begs the question ‘‘Does the mere fact that humans and apes look similar imply that they
evolved from common ancestors?’’ And the third and fourth beg the questions ‘‘Just because the poor
earn less than the average citizen, does this imply that the government should give them handouts?’’ and
‘‘Just because terminally ill patients cannot commit suicide by themselves, why does it follow that they
have a right to a doctor’s assistance?’’
These questions indicate that something has been left out of the original arguments. Thus, the first
argument is missing the premise, ‘‘Abortion is a form of murder’’; the second is missing the premise,
‘‘the fact that humans and apes look similar implies that they have common ancestors’’; and so on. These
premises are crucial for the soundness of the arguments. If the arguer is unable to establish the truth of
these premises, then the arguments prove nothing. However, in most cases of begging the question, this is
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precisely the reason why such premises are left unstated. The arguer is not able to establish their truth,
and by employing rhetorical phraseology such as ‘‘of course,’’ ‘‘clearly,’’ ‘‘this being the case,’’ and
‘‘after all,’’ the arguer hopes to create the illusion that the stated premise, by itself, provides adequate
support for the conclusion when in fact it does not.
The same form of begging the question often appears in arguments concerning religious topics, to justify
conclusions about the existence of God, the immortality of the soul, and so on. Example:
The world in which we live displays an amazing degree of organization. Obviously this world was created by an intelligent God.
This argument begs the question, ‘‘How do you know that the organization in the world could only have
come from an intelligent creator?’’ Of course the claim that it did come from an intelligent creator may
well be true, but the burden is on the arguer to prove it. Without supporting reasons or evidence, the
argument proves nothing.
Yet, most people who are predisposed to believe the conclusion are likely to accept the argument as a
good one. The same can be said of most arguments that beg the question, and this fact suggests another
reason why arguers resort to this fallacy: Such arguments tend to reinforce preexisting inclinations and
beliefs.
The second form of petitio principii occurs when the premise of an argument merely restates the
conclusion in slightly different language. Examples:
Capital punishment is justified for the crimes of murder and kidnapping because it is quite legitimate and appropriate that
someone be put to death for having committed such hateful and inhuman acts.
Anyone who preaches revolution has a vision of the future for the simple reason that if a person has no vision of the future he
could not possibly preach revolution.
In the first argument, saying that capital punishment is ‘‘justified’’ means the same thing as saying that it
is ‘‘legitimate and appropriate,’’ and in the second argument the premise and the conclusion say exactly
the same thing. However, by repeating the same thing in slightly different language, the arguer creates the
illusion that independent evidence is being presented in support of the conclusion, when in fact it is not.
Both arguments contain rhetorical phraseology (‘‘hateful and inhuman,’’ ‘‘simple reason,’’ and ‘‘could
not possibly’’) that help effect the illusion. The first argument begs the question, ‘‘How do you know that
capital punishment really is legitimate and appropriate?’’ and the second begs the question, ‘‘How do you
know that people who preach revolution really do have a vision of the future?’’
The third form of petitio principii involves circular reasoning in a chain of inferences.
Here is an example: Ford Motor Company clearly produces the finest cars in the United States. We know they produce the
finest cars because they have the best design engineers. This is true because they can afford to pay them more than other
manufacturers. Obviously they can afford to pay them more because they produce the finest cars in the United States.
Upon encountering this argument, the attentive reader is inclined to ask, ‘‘where does this reasoning
begin? What is its source?’’ Since the argument goes in a circle, it has no beginning or source, and as a
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result it proves nothing. Of course, in this example the circularity is rather apparent, so the argument is
not likely to convince anyone. Cases in which circular reasoning may convince involve long and complex
arguments having premises that depend on one another in subtle ways and a key premise that depends on
the conclusion.
In all cases of begging the question, the arguer uses some linguistic device to create the illusion that
inadequate premises provide adequate support for a conclusion. Without such an illusion, the fallacy is
not committed. Thus, the following arguments commit no fallacy:
No dogs are cats.
Therefore, no cats are dogs.
London is in England and Paris is in France.
Therefore, Paris is in France and London is in England.
In both of these examples, the premise amounts to little more than a restatement of the conclusion. Yet,
both arguments are sound because they are valid and have true premises. No fallacy is committed because
no illusion is created to make inadequate premises appear as adequate. We will study arguments of this
sort in Chapters 4 and 7.
Here is another example:
Rome is in Germany or Rome is in Germany.
Therefore, Rome is in Germany.
This argument is valid, but it is unsound because it has a false premise. However, it commits no fallacy
because, again, no illusion is created to cover anything up. Arguments having this form also appear in
Chapter 7.
As with these examples, arguments that beg the question are normally valid. This is easy to see. Any
argument that includes the conclusion as one of the premises is clearly valid, and those forms of the
fallacy that leave a key premise out of the argument become valid when that key premise is introduced.
The problem with arguments that beg the question is that they are usually unsound, or at least not clearly
sound, because the premise needed to provide adequate support for the conclusion is, at best, of uncertain
truth value. Because such arguments presume the truth of this premise, begging the question is called a
fallacy of presumption.
16. Complex Question: The fallacy of complex question is committed when a single question that is
really two (or more) questions is asked and a single answer is then applied to both questions.
Every complex question presumes the existence of a certain condition. When the respondent’s answer is
added to the complex question, an argument emerges that establishes the presumed condition. Thus,
although not an argument as such, a complex question involves an implicit argument. This argument is
usually intended to trap the respondent into acknowledging something that he or she might otherwise not
want to acknowledge. Examples:
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Have you stopped cheating on exams?
Where did you hide the cookies you stole?
Let us suppose the respondent answers ‘‘yes’’ to the first question and ‘‘under the bed’’ to the second.
The following arguments emerge:
You were asked whether you have stopped cheating on exams. You answered ‘‘yes.’’ Therefore, it follows that you have cheated
in the past.
You were asked where you hid the cookies you stole. You replied ‘‘under the bed.’’ It follows that you did in fact steal the
cookies.
On the other hand, let us suppose that the respondent answers ‘‘no’’ to the first question and ‘‘nowhere’’
to the second.We then have the following arguments:
You were asked whether you have stopped cheating on exams. You answered
‘‘no.’’ Therefore, you continue to cheat.
You were asked where you hid the cookies you stole. You answered ‘‘nowhere.’’
It follows that you must have stolen them and eaten them.
Obviously, each of the questions is really two questions:
Did you cheat on exams in the past? If you did cheat in the past, have you stopped now?
Did you steal the cookies? If you did steal them, where did you hide them?
If respondents are not sophisticated enough to identify a complex question when one is put to them, they
may answer quite innocently and be trapped by a conclusion that is supported by no evidence at all; or,
they may be tricked into providing the evidence themselves. The correct response lies in resolving the
complex question into its component questions and answering each separately.
The fallacy of complex question should be distinguished from another kind of question known in law as a
leading question. A leading question is one in which the answer is in some way suggested in the question.
Whether or not a question is a leading one is important in the direct examination of a witness by counsel.
Example:
Tell us, on April 9, did you see the defendant shoot the deceased? (Leading question)
Tell us, what did you see on April 9? (Straight question)
Leading questions differ from complex questions in that they involve no logical fallacies; that is, they do
not attempt to trick the respondent into admitting something he or she does not want to admit. To
distinguish the two, however, it is sometimes necessary to know whether prior questions have been asked.
Here are some additional examples of complex questions:
Are you going to be a good little boy and eat your hamburger?
Is George Hendrix still smoking marijuana?
How long must I put up with your snotty behavior?
When are you going to stop talking nonsense?
17. False Dichotomy: The fallacy of false dichotomy (otherwise called ‘‘false bifurcation’’ and the
‘‘either/or fallacy’’) is committed when one premise of an argument is an ‘‘either . . . or . . .’’
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(disjunctive) statement that presents two alternatives as if they were jointly exhaustive (as if no third
alternative were possible). One of these alternatives is usually preferred by the arguer. When the arguer
then proceeds to eliminate the undesirable alternative, the desirable one is left as the conclusion. Such an
argument is clearly valid; but since the disjunctive premise is usually false, the argument is almost always
unsound. Of course, not all unsound arguments are fallacious. The fallacious nature of false dichotomy
lies in the attempt by the arguer to delude the reader or listener into thinking that the disjunctive premise
presents jointly exhaustive alternatives and is therefore true by necessity. The fallacy is commonly
committed by children and adolescents when arguing with their parents, by advertisers, and by adults
generally. Here are some examples:
Either you let me attend the Garth Brooks concert or I’ll be miserable for the rest of my life. I know you don’t want me to be
miserable for the rest of my life, so it follows that you’ll let me attend the concert.
Either you use Ultra Guard deodorant or you risk the chance of perspiration odor. Surely you don’t want to risk the chance of
perspiration odor. Therefore, you will want to use Ultra Guard deodorant.
Either you buy only American-made products or you don’t deserve to be called a loyal American. Yesterday you bought a new
Toyota. It’s therefore clear that you don’t deserve to be called a loyal American.
None of the disjunctive premises in these arguments presents alternatives that are jointly exhaustive. Yet
in each case the arguer wants to make it appear that it does. For example, in the first argument the arguer
wants to convey the illusion that either he or she goes to the concert or faces a lifetime of misery, and no
other alternatives are possible. Clearly, however, such is not the case.
False dichotomy is classified as a fallacy of presumption because the soundness of the argument depends
on the presumption that the two alternatives presented are the only ones that exist. If they are not the only
ones that exist, the ‘‘either . . . or . . .’’ statement is false, and the argument is unsound.
Most instances of false dichotomy are not presented as complete arguments. Only the disjunctive premise
is expressed, and the arguer leaves it to the reader or listener to supply the missing parts:
Either you buy me a new mink coat, or I’ll freeze to death when winter comes.
Either I continue smoking, or I’ll get fat and you’ll hate to be seen with me.
The missing premise and conclusion are easily introduced.
18. Suppressed Evidence: Chapter 1 explained that a cogent argument is an inductive argument with
good reasoning and true premises. The requirement of true premises includes the proviso that the
premises not ignore some important piece of evidence that outweighs the presented evidence and entails a
very different conclusion. If an inductive argument does indeed ignore such evidence, then the argument
commits the fallacy of suppressed evidence. Consider, for example, the following argument:
Most dogs are friendly and pose no threat to people who pet them. Therefore, it would be safe to pet the little dog that is
approaching us now.
If the arguer ignores the fact that the little dog is excited and foaming at the mouth (which suggests
rabies), then the argument commits a suppressed evidence fallacy.
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This fallacy is classified as a fallacy of presumption because it works by creating the presumption that the
premises are both true and complete when in fact they are not. Perhaps the most common occurrence of
the suppressed evidence fallacy appears in inferences based on advertisements. Nearly every ad neglects
to mention certain negative features of the product advertised. As a result, an observer who sees or hears
an advertisement and then draws a conclusion from it may commit the fallacy of suppressed evidence.
Example: The new RCA Digital Satellite System delivers sharp TV reception from an 18-inch dish antenna, and it costs only
$199. Therefore, if we buy it, we can enjoy all the channels for a relatively small one-time investment.
The ads for the Digital Satellite System fail to mention that the user must also pay a substantial monthly
fee to the satellite company and that none of the local channels are carried by the system. Thus, if the
observer takes the ads at face value and uses them as the basis for such an argument, the argument will be
fallacious.
Another way that an arguer can commit the suppressed evidence fallacy is by ignoring important events
that have occurred with the passage of time that render an inductive conclusion improbable. Here is an
example:
During the past fifty years, Poland has enjoyed a rather low standard of living. Therefore, Poland will probably have a low
standard of living for the next fifty years.
This argument ignores the fact that Poland was part of the Soviet bloc during most of the past fifty years,
and this fact accounts for its rather low standard of living. However, following the collapse of the Soviet
Union, Poland became an independent nation, and its economy is expected to improve steadily during the
next fifty years.
Yet another form of suppressed evidence is committed by arguers who quote passages out of context from
sources such as the Bible, the Constitution, and the Bill of Rights to support a conclusion that the passage
was not intended to support. Consider, for example, the following argument against gun control:
The Second Amendment to the Constitution states that the right of the people to keep and bear arms shall not be infringed. But a
law controlling handguns would infringe the right to keep and bear arms. Therefore, a law controlling handguns would be
unconstitutional.
In fact, the Second Amendment reads, ‘‘A well regulated militia, being necessary to the security of a free
state, the right of the people to keep and bear arms, shall not be infringed.’’ In other words, the
amendment states that the right to bear arms shall not be infringed when the arms are necessary for the
preservation of a well-regulated militia.
Because a law controlling handguns (pistols) would have little effect on the preservation of a well-
regulated militia, it is unlikely that such a law would be unconstitutional. The suppressed evidence fallacy
is similar to the form of begging the question in which the arguer leaves a key premise out of the
argument. The difference is that suppressed evidence leaves out a premise that requires a different
conclusion, while that form of begging the question leaves out a premise that is needed to support the
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stated conclusion. However, because both fallacies proceed by leaving a premise out of the argument,
there are cases where the two fallacies overlap.
19. Equivocation: The fallacy of equivocation occurs when the conclusion of an argument depends on
the fact that a word or phrase is used, either explicitly or implicitly, in two different senses in the
argument. Such arguments are either invalid or have a false premise, and in either case they are unsound.
Examples:
Some triangles are obtuse. Whatever is obtuse is ignorant. Therefore, some triangles are ignorant.
Any law can be repealed by the legislative authority. But the law of gravity is a law. Therefore, the law of gravity can be repealed
by the legislative authority.
We have a duty to do what is right. We have a right to speak out in defense of the innocent. Therefore, we have a duty to speak
out in defense of the innocent.
A mouse is an animal. Therefore, a large mouse is a large animal.
In the first argument ‘‘obtuse’’ is used in two different senses. In the first premise it describes a certain
kind of angle, while in the second it means dull or stupid. The second argument equivocates on the word
‘‘law.’’ In the first premise it means statutory law, and in the second it means law of nature. The third
argument uses ‘‘right’’ in two senses. In the first premise ‘‘right’’ means morally correct, but in the
second it means a just claim or power. The fourth argument illustrates the ambiguous use of a relative
term. The word ‘‘large’’ means different things depending on the context. Other relative terms that are
susceptible to this same kind of ambiguity include ‘‘small,’’ ‘‘good,’’ ‘‘bad,’’ ‘‘light,’’ ‘‘heavy,’’
‘‘difficult,’’ ‘‘easy,’’ ‘‘tall,’’ ‘‘short,’’ and so on.
To be convincing, an argument that commits an equivocation must use the equivocal word in ways that
are subtly related. Of the three examples given above, only the third might fulfill this requirement. Since
both uses of the word ‘‘right’’ are related to ethics, the unalert observer may not notice the shift in
meaning. Another technique is to spread the shift in meaning out over the course of a lengthy argument.
Political speechmakers often use phrases such as ‘‘equal opportunity,’’ ‘‘gun control,’’ ‘‘national
security,’’ and ‘‘environmental protection’’ in one way at the beginning of a speech and in quite another
way at the end. A third technique consists in using such phrases one way in a speech to one group and in a
different way in a speech to an opposing group. If the same people are not present at both speeches, the
equivocation is not detected.
20. Amphiboly: The fallacy of amphiboly occurs when the arguer misinterprets a statement that is
syntactically ambiguous and proceeds to draw a conclusion based on this faulty interpretation.
The original statement is usually asserted by someone other than the arguer, and the syntactical ambiguity
usually arises from a mistake in grammar or punctuation—a missing comma, a dangling modifier, an
ambiguous antecedent of a pronoun, or some other careless arrangement of words. Because of this
ambiguity, the statement may be understood in two clearly distinguishable ways. The arguer typically
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selects the unintended interpretation and proceeds to draw a conclusion based upon it. Here are some
examples:
The tour guide said that standing in Greenwich Village, the Empire State Building could easily be seen. It follows that the Empire
State Building is in Greenwich Village.
John told Henry that he had made a mistake. It follows that John has at least the courage to admit his own mistakes.
Professor Johnson said that he will give a lecture about heart failure in the biology lecture hall. It must be the case that a number
of heart failures have occurred there recently.
The premise of the first argument contains a dangling modifier. Is it the observer or the Empire State
Building that is supposed to be standing in Greenwich Village? The correct interpretation is the former. In
the second argument the pronoun ‘‘he’’ has an ambiguous antecedent; it can refer either to John or to
Henry. Perhaps John told Henry that Henry had made a mistake. In the third argument the ambiguity
interpretation is probably the former. The ambiguity can be eliminated by inserting commas (‘‘Professor
Johnson said that he will give a lecture, about heart failure, in the biology lecture hall’’) or by moving the
ambiguous modifier (‘‘Professor Johnson said that he will give a lecture in the biology lecture hall about
heart failure’’).
Two areas where cases of amphiboly cause serious problems involve contracts and wills. The drafters of
these documents often express their intentions in terms of ambiguous statements, and alternate
interpretations of these statements then lead to different conclusions. Examples:
Mrs. Hart stated in her will, ‘‘I leave my 500-carat diamond necklace and my pet chinchilla to Alice and Theresa.’’ Therefore, we
conclude that Alice gets the necklace and Theresa gets the chinchilla.
Mr. James signed a contract that reads, ‘‘In exchange for painting my house, I promise to pay David $5000 and give him my new
Cadillac only if he finishes the job by May 1.’’ Therefore, since David did not finish until May 10, it follows that he gets neither
the $5000 nor the Cadillac.
In the first example, the conclusion obviously favors Alice. Theresa is almost certain to argue that the gift
of the necklace and chinchilla should be shared equally by her and Alice. Mrs. Hart could have avoided
the dispute by adding either ‘‘respectively’’ or ‘‘collectively’’ to the end of the sentence. In the second
example, the conclusion favors Mr. James. David will argue that the condition that he finish by May 1
affected only the Cadillac and that he therefore is entitled to the $5000. The dispute could have been
avoided by properly inserting a comma in the language of the promise.
Amphiboly differs from equivocation in two important ways. First, equivocation is always traced to an
ambiguity in the meaning of a word or phrase, whereas amphiboly involves a syntactical ambiguity in a
statement. The second difference is that amphiboly usually involves a mistake made by the arguer in
interpreting an ambiguous statement made by someone else, whereas the ambiguity in equivocation is
typically the arguer’s own creation. If these distinctions are kept in mind, it is usually easy to distinguish
amphiboly from equivocation. Occasionally, however, the two fallacies occur together, as the following
example illustrates:
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The Great Western Cookbook recommends that we serve the oysters when thoroughly stewed. Apparently the delicate flavor is
enhanced by the intoxicated condition of the diners.
First, it is unclear whether ‘‘stewed’’ refers to the oysters or to the diners, and so the argument commits
an amphiboly. But if ‘‘stewed’’ refers to the oysters it means ‘‘cooked,’’ and if it refers to the diners it
means ‘‘intoxicated.’’ Thus, the argument also involves an equivocation.
21. Composition: The fallacy of composition is committed when the conclusion of an argument
depends on the erroneous transference of an attribute from the parts of something onto the whole. In other
words, the fallacy occurs when it is argued that because the parts have a certain attribute, it follows that
the whole has that attribute too and the situation is such that the attribute in question cannot be
legitimately transferred from parts to whole.
Examples:
Maria likes anchovies. She also likes chocolate ice cream. Therefore, it is certain that she would like a chocolate sundae topped
with anchovies.
Each player on this basketball team is an excellent athlete. Therefore, the team as a whole is excellent.
Each atom in this piece of chalk is invisible. Therefore, the chalk is invisible.
Sodium and chlorine, the atomic components of salt, are both deadly poisons. Therefore, salt is a deadly poison.
In these arguments the attributes that are transferred from the parts onto the whole are designated by the
words ‘‘Maria likes,’’ ‘‘excellent,’’ ‘‘invisible,’’ and ‘‘deadly poison,’’ respectively.
In each case the transference is illegitimate, and so the argument is fallacious.
Not every such transference is illegitimate, however. Consider the following arguments:
Every atom in this piece of chalk has mass. Therefore, the piece of chalk has mass.
Every component in this picket fence is white. Therefore, the whole fence is white.
In each case an attribute (having mass, being white) is transferred from the parts onto the whole, but these
transferences are quite legitimate. Indeed, the fact that the atoms have mass is the very reason why the
chalk has mass. The same reasoning extends to the fence. Thus, the acceptability of these arguments is
attributable, at least in part, to the legitimate transference of an attribute from parts onto the whole.
These examples illustrate the fact that the fallacy of composition is indeed an informal fallacy. It cannot
be discovered by a mere inspection of the formof an argument—that is, by the mere observation that an
attribute is being transferred from parts onto the whole. In addition, detecting this fallacy requires a
general knowledge of the situation and of the nature of the attribute being transferred. The critic must be
certain that, given the situation, the transference of this particular attribute is not allowed.
Further caution is required by the fact that composition is sometimes confused with hasty generalization.
The only time this confusion is possible is when the ‘‘whole’’ is a class (such as the class of people in a
city or the class of trees in a forest), and the ‘‘parts’’ are the members of the class. In such a case
composition proceeds from the members of the class to the class itself. Hasty generalization, on the other
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hand, proceeds from the specific to the general. Because it is sometimes easy to mistake a statement about
a class for a general statement, composition can be mistaken for hasty generalization. Such a mistake can
be avoided if one is careful to keep in mind the distinction between these two kinds of statements. This
distinction falls back on the difference between the collective and the distributive predication of an
attribute.
Consider the following statements:
Fleas are small.
Fleas are numerous.
The first statement is a general statement. The attribute of being small is predicated distributively; that is,
it is assigned (or distributed) to each and every flea in the class. Each and every flea in the class is said to
be small. The second statement, on the other hand, is a statement about a class as a whole, or what we will
call a ‘‘class statement.’’ The attribute of being numerous is predicated collectively; in other words, it is
assigned not to the individual fleas but to the class of fleas. The meaning of the statement is not that each
and every flea is numerous but that the class of fleas is large.
To distinguish composition from hasty generalization, therefore, the following procedure should be
followed. Examine the conclusion of the argument. If the conclusion is a general statement—that is, a
statement in which an attribute is predicated distributively to each and every member of a class—the
fallacy committed is hasty generalization.
But if the conclusion is a class statement—that is, a statement in which an attribute is predicated
collectively to a class as a whole—the fallacy is composition.
Example:
Less gasoline is consumed by a car than by a truck. Therefore, less gasoline is consumed in the United States by cars than by
trucks.
At first sight this argument might appear to proceed from the specific to the general and, consequently, to
commit a hasty generalization. But in fact the conclusion is not a general statement at all but a class
statement. The conclusion states that the whole class of cars uses less gas than does the whole class of
trucks (which is false, because there are many more cars than trucks). Since the attribute of using less
gasoline is predicated collectively, the fallacy committed is composition.
22. Division: The fallacy of division is the exact reverse of composition. As composition goes from
parts to whole, division goes from whole to parts. The fallacy is committed when the conclusion of an
argument depends on the erroneous transference of an attribute from a whole (or a class) onto its parts (or
members). Examples:
Salt is a nonpoisonous compound. Therefore, its component elements, sodium and chlorine, are nonpoisonous.
This jigsaw puzzle, when assembled, is circular in shape. Therefore, each piece is circular in shape.
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The Royal Society is over 300 years old. Professor Thompson is a member of the Royal Society. Therefore, Professor Thompson
is over 300 years old.
In each case the attribute, designated respectively by the terms ‘‘nonpoisonous,’’ ‘‘circular in shape,’’ and
‘‘over 300 years old,’’ is illegitimately transferred from the whole or class onto the parts or members. As
with the fallacy of composition, however, this kind of transference is not always illegitimate. The
following arguments contain no fallacy:
This piece of chalk has mass. Therefore, the atoms that compose this piece of chalk have mass.
This field of poppies is uniformly orange in color. Therefore, the individual poppies are orange in color.
Obviously, one must be acquainted with the situation and the nature of the attribute being transferred to
decide whether the fallacy of division is actually committed. Just as composition is sometimes prone to
being confused with hasty generalization (converse accident), division is sometimes prone to being
confused with accident. As with composition, this confusion can occur only when the ‘‘whole’’ is a class.
In such a case, division proceeds from the class to the members, while accident proceeds from the general
to the specific. Thus, if a class statement is mistaken for a general statement, division may be mistaken for
accident. To avoid such a mistake, one should analyze the premises of the argument. If the premises
contain a general statement, the fallacy committed is accident; but if they contain a class statement, the
fallacy is division.
Example:
Stanley Steamers have almost disappeared.
This car is a Stanley Steamer.
Therefore, this car has almost disappeared.
The first premise is not a general statement but a class statement. The attribute of having almost
disappeared is predicated collectively. Accordingly, the fallacy committed is division, not accident.
This example also illustrates how cases of division that involve class statements can include a subtle form
of equivocation. In the conclusion, the word ‘‘disappeared’’ means fading from vision, as when the lights
are turned down; but in the first premise it means rarely seen. The equivocation is a kind of secondary
fallacy that results from the primary fallacy, which is division.
The next example shows how division turns up in arguments dealing with averages.
The average American family has 2.5 children.
The Jones family is an average American family.
Therefore, the Jones family has 2.5 children.
The statement ‘‘the average American family has 2.5 children’’ is not a general statement, but rather a
class statement. The sense of the statement is not that each and every family has 2.5 children, but that the
class of families is reducible to 55 percent children and 45 percent adults. Thus, once again, the fallacy is
division, and not accident. In our account of composition and division, we have presented examples of
arguments that commit these fallacies in conjunction with other, structurally similar arguments that do
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not. Because of the structural similarity between arguments that do and do not commit these fallacies,
composition and division are classified as fallacies of grammatical analogy.
Avoiding Fallacies: Why do people commit informal fallacies? Unfortunately, this question admits
of no simple, straightforward answer. The reasons underlying the commission of fallacies are complex
and interconnected. However, we can identify three factors that lead to most of the informal mistakes in
reasoning. The first is intent. Many fallacies are committed intentionally. The arguer may know full well
that his or her reasoning is defective but goes ahead with it anyway because of some benefit for himself or
herself or some other person. All of the informal fallacies we have studied can be used for that purpose,
but some of them are particularly well suited. These include the appeal to force, appeal to pity, appeal to
the people, straw man, ad hominem, complex question, false dichotomy, and suppressed evidence. Here is
such a case of appeal to force:
I deserve a chocolate sundae for dessert, and if you don’t buy me one right now, I’ll start screaming and embarrass you in front of
all of the people in this restaurant.
And here is a case of false dichotomy that conveys the appearance of being intentionally committed:
Either you take me on a Caribbean cruise, or I’ll have a nervous breakdown. It’s up to you.
The key to avoiding fallacies that are intentionally committed probably lies in some form of moral
education. The arguer must come to realize that using intellectually dishonest means to acquire something
he or she does not deserve is just another form of cheating.
The situation becomes more complicated, however, when the sought-after goal is morally justified.
Arguers sometimes use fallacious reasoning intentionally to trick a person into doing something that is
really for that person’s own good. Here is a false dichotomy of that sort:
Either you control your eating and get regular exercise, or you’ll have a heart attack and die. The choice is yours.
Given the beneficial consequences of controlled eating and regular exercise, some moral philosophers
will find nothing wrong with this argument. Others will contend that manipulating someone into doing
something violates human dignity. In either event, such arguments are logically unacceptable.
The second factor that leads to the commission of informal fallacies is a careless mental posture
combined with an emotional disposition favoring or opposing some person or thing. The careless mental
posture opens the door, so to speak, to fallacious reasoning, and the emotional disposition pushes the
arguer through it. Even people who are thoroughly versed in the informal fallacies occasionally succumb
to the deadly combination of mental carelessness and emotional impetus. For example, arguments such as
the following ad hominem abusive can sometimes be heard in the halls of university philosophy
departments:
Professor Ballard’s argument in favor of restructuring our course offering isn’t worth a hoot. But what would you expect from
someone who publishes in such mediocre journals. And did you hear Ballard’s recent lecture on Aristotle? It was total nonsense.
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When people who should know better are confronted with the fact that their argument commits a common
fallacy, they often admit with embarrassment that they have not been thinking and then revise their
argument according to logical principles. In contrast, people who are not familiar with the distinction
between good and fallacious reasoning will likely deny that there is anything wrong with their argument.
Thus, the key to avoiding fallacies that arise from mental carelessness lies in developing a thorough
familiarity with the informal fallacies combined with a habitual realization of how emotions affect
people’s reasoning. Everyone should realize that unchecked emotions are an open invitation to illogical
reasoning, and they can lead a person to commit quite blindly every one of the fallacies we have studied
thus far.
The third factor that leads to the commission of informal fallacies is far more difficult to contend with
than the first two. It consists in the influence of what we might call the ‘‘worldview’’ of the arguer. By
worldview we mean a cognitive network of beliefs, attitudes, habits, memories, values, and other
elements that conditions and renders meaningful the world in which we live. Beginning in infancy, our
worldview emerges quietly and unconsciously from enveloping influences—culture, language, gender,
religion, politics, and social and economic status. As we grow older, it continues to develop through the
shaping forces of education and experience. Once it has taken root, our worldview determines how each
of us sizes up the world in which we live. Given a set of circumstances, it indicates what is reasonable to
believe and what is unreasonable.
In connection with the construction and evaluation of arguments, an arguer’s worldview determines the
answer to questions about importance, relevance, causal connections, the qualifications of authorities,
whether a sample is typical or atypical of a group, what can and cannot be taken for granted, and other
factors. However, because these determinations inevitably involve unexamined presuppositions, the
arguer’s worldview can lead to the commission of informal fallacies. All of the fallacies we have studied
so far are likely candidates, but the ones especially susceptible are appeal to pity, straw man, missing the
point, appeal to unqualified authority, hasty generalization, false cause, slippery slope, weak analogy,
begging the question, false dichotomy, and suppressed evidence.
Thus, a person with a victim mentality may think that his pathetic circumstances really justify some
favorable treatment; an uncritical conservative may cite with complete confidence the authority of Rush
Limbaugh; a person with a racist worldview may conclude that the errant behavior of a handful of Asians,
African Americans, or Hispanics really is typical of the larger class; a person with a liberal worldview
may quite innocently distort an opponent’s argument by equating it with fascism; a pro-life arguer may
consider it obvious that the fetus is a person with rights, while a pro-choice arguer may take it for granted
that the fetus is not a person with rights, and so on.
Consider, for example, the following argument from analogy:
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A court trial is like a professional football game. In a professional football game, the most important thing is winning. Similarly,
in a trial, the most important thing is winning.
This argument is consistent with the worldview of many, if not most, lawyers. Lawyers are trained as
advocates, and when they enter a courtroom they see themselves going into battle for their clients. In any
battle, winning is the most important objective. But this viewpoint presupposes that truth and justice are
either unattainable in the courtroom or of secondary importance. Thus, while many lawyers would
evaluate this argument as non-fallacious, many non-lawyers would reject it as a weak analogy.
For another example, consider the following causal inference:
After enslaving most of Eastern Europe for nearly fifty years, the evil Soviet empire finally collapsed. Obviously God listened to
our prayers.
This argument reflects the worldview of many theists. It presupposes that there is a God, that God listens
to prayers, that God is affected by prayers, that God has the power to influence the course of history, and
that God does influence the course of history. While the theist is likely to consider this argument a good
one, the atheist will reject it as a blatant case of false cause.
To avoid fallacies that arise from the influence of worldviews, the arguer must acknowledge and critique
his or her presuppositions. Doing so inclines the arguer to couch his or her arguments in language that
takes those presuppositions into account.
The result is nearly always an argument that is more intelligently formed, and, it is hoped, more
persuasive. However, the task of recognizing and critiquing one’s presuppositions is not easy.
Presuppositions are intrinsically linked to one’s worldview, and many people are not even aware that they
have a worldview. The reason is that worldviews are formed through a process that is largely
unconscious. Thus, the arguer must first recognize that he or she has a worldview and must then exercise
constant vigilance over the presuppositions it comprises.
Even after one’s presuppositions have been exposed and thoroughly critiqued, however, there is no
guarantee that one’s arguments will agree with the arguments of others who have critiqued their
worldviews. This is because a person’s worldview reflects the unique perspective that person has on the
world. No two people share exactly the same perspective. Nevertheless, disclosing and critiquing the
presuppositions in one’s worldview lays a foundation for meaningful communication with other
reasonable arguers, and it provides a context of reasonableness for working out disagreements.
In summary, the three factors that are probably responsible for most informal fallacies are intention,
mental carelessness combined with emotional dispositions, and unexamined worldviews. However, these
factors rarely occur in isolation. In the vast majority of cases, two, or all three, conspire to produce
fallacious reasoning. This fact exacerbates the difficulty in avoiding informal fallacies in one’s own
arguments and in detecting fallacies in the arguments of others.
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Now let us consider some cases of real-life arguments in light of the factors we have just discussed. All
are taken from letters to the editors of newspapers and magazines.
The first relates to affirmative action programs:
I’m a nonracist, nonsexist, white male born in 1969, who has never owned a slave, treated anyone as inferior because of his or
her race, or sexually harassed a female co-worker. In other words, I don’t owe women or minorities a thing. Since when are
people required to pay for the sins of their predecessors simply because they belong to the same race or gender. (Ben Gibbons)
The author of this argument presupposes that racist and sexist patterns in society have not benefitted him
in any way. Among other things, he presupposes that his white ancestors in no way benefitted from their
being white and that none of these benefits passed down to him. On the other hand, given that he has
received such benefits, he may presuppose that he is not obligated to pay any of them back. Of course
none of these things may have occurred, but the author should at least address these issues. Because he
does not address them, the argument begs the question.
The next argument relates to second-hand smoke from cigarettes:
Now, besides lung cancer and other nasty business, second-hand smoke causes deafness and impotence. Was second-hand smoke
a problem when people heated their homes solely by fireplaces? How about those romantic teepees with the smoke hole at the
top? And what about fireplaces in new homes? Let’s have some research about the problems caused by these as well as
barbecues. A little cancer with your hot dog, anyone? (Pat Sharp)
This argument seems to commit the fallacy of equivocation. The arguer begins by using ‘‘second-hand
smoke’’ to refer to the smoke from burning tobacco, and then uses the termto refer to the smoke from
fireplaces, teepee fires, and barbecues. Smoke from burning tobacco is clearly not the same thing as
smoke from burning wood or charcoal. Alternately, the argument might be seen to beg the question: ‘‘But
do people burn tobacco in their fireplaces and barbecues?’’ These fallacies probably arise either from the
intentions of the author or from carelessness in failing to distinguish the two kinds of second-hand smoke.
In either event, the author is probably hostile to government efforts to control second-hand tobacco smoke
in confined areas.
The next argument deals with gun control:
Detroit, the seventh largest city and one with strict gun laws, had 596 homicides in 1992. In the same year Phoenix, the ninth
largest city and one that at the time did not require gun owners to be licensed, had 136 homicides. Criminals don’t fear the
toothless criminal-justice system, but they do fear armed citizens. (Paul M. Berardi)
This argument commits a false cause fallacy. The author presupposes that the availability of guns caused
Phoenix to have a lower homicide rate than Detroit. The arguer also presupposes that Detroit and Phoenix
are comparable as to homicide rate merely because they are roughly the same size. As a result, the
argument also begs the question.
The additional factors of emotion and intent may also be present. The arguer probably hates the prospect
of gun control, and he may be fully aware of the fact that Phoenix and Detroit are not comparable for his
purpose, but he went ahead with the comparison anyway.
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The next argument deals with religious fundamentalism:
If we compromise God’s word, we compromise the truth. To say that the fundamentalist is a loud shrill voice drowning out
religious moderation implies that diluted truth is better than absolute truth. (Gerald Gleason)
This argument begs the question. The arguer presupposes that there is a God that God has spoken, that
God has revealed his intentions to fundamentalist preachers, and that those preachers accurately report the
word of God. The argument also seems to reflect an emotional disposition in favor of religious
fundamentalism.
The last argument we will consider relates to English as the official U.S. language:
This great country has been held together for more than 200 years because of one simple thing: the English language. There are
two things we must do: Make English the official language of the United States and do away with bilingual education. (David
Moisan)
This argument misses the point. The arguer presupposes that making English the official language would
guarantee that all citizens speak it and that doing away with bilingual education would accelerate the
learning process of immigrant children. The argument may also reflect the fear that many feel in connecti
SUMMARY OF INFORMAL FALLACIES
I. FALLACIES of Relevance
Appeal to force: Arguer threatens reader/listener.
Appeal to pity: Arguer elicits pity from reader/listener.
Appeal to the people (direct): Arguer arouses mob mentality.
Appeal to the people (indirect): Arguer appeals to reader/listener’s desire for security, love, respect, etc.
Argument against the person (abusive): Arguer verbally abuses other arguer.
Argument against the person (circumstantial): Arguer presents other arguer as predisposed to argue
this way.
Argument against the person (tu quoque): Arguer presents other arguer as hypocrite.
Accident: General rule is applied to a specific case it was not intended to cover.
Straw man: Arguer distorts opponent’s argument and then attacks the distorted argument.
Missing the point: Arguer draws conclusion different from that supported by premises
Red herring: Arguer leads reader/listener off track.
II. Fallacies of Weak Induction
Appeal to unqualified authority: Arguer cites untrustworthy authority.
Appeal to ignorance: Premises report that nothing is known or proved, and then a conclusion is drawn.
Hasty generalization: Conclusion is drawn from atypical sample.
False cause: Conclusion depends on nonexistent or minor causal connection.
Slippery slope: Conclusion depends on unlikely chain reaction.
35

Weak analogy: Conclusion depends on defective analogy.
III. Fallacies of Presumption
Begging the question: Arguer creates the illusion that inadequate premises are adequate by leaving out a
key premise, or by restating the conclusion as a premise, or by reasoning in a circle.
Complex question: Multiple questions are concealed in a single question.
False dichotomy: ‘‘Either . . . or . . .’’ statement hides additional alternatives.
Suppressed evidence: Arguer ignores important evidence that requires a different conclusion.
IV. Fallacies of Ambiguity
Equivocation: Conclusion depends on a shift in meaning of a word or phrase.
Amphiboly: Conclusion depends on the wrong interpretation of a syntactically ambiguous statement.
V. Fallacies of Grammatical Analogy
Composition: Attribute is wrongly transferred from parts to whole.
Division: Attribute is wrongly transferred from whole to parts.
Succinct Summary of Informal Fallacies: A fallacy is a mistake in an argument that arises
from something other than merely false premises. Usually fallacies involve defects in reasoning or the
creation of an illusion that makes a bad argument appear good. Fallacies can be either formal or informal.
A formal fallacy is one that can be detected by analyzing the form of an argument; such fallacies affect
only deductive arguments. An informal fallacy is one that can be identified only by analyzing the content
of an argument; such fallacies can affect both deductive and inductive arguments.
The fallacies of relevance occur when the premises of an argument are not relevant to the conclusion.
Cases of such irrelevance occur in premises that threaten the observer, elicit pity from the observer, create
a mob mentality in a group of observers, appeal to the observer’s desire for security, verbally abuse an
opposing arguer, present an opposing arguer as predisposed to argue as he does, present an opposing
arguer as a hypocrite, misapply a general rule, distort an opponent’s argument, or lead the observer off the
track. A kind of catch-all fallacy, missing the point, occurs when an arguer draws a conclusion different
from the one implied by the premises.
The fallacies of weak induction occur when the premises, although possibly relevant to the conclusion,
provide insufficient support for the conclusion. Cases of such inadequate support occur when the arguer
cites an authority who is not qualified, draws a conclusion from premises that give no positive evidence,
draws a conclusion from an atypical sample, depends on a nonexistent or minor causal connection,
depends on a chain reaction that is unlikely to occur, or draws a conclusion from an analogy that is not
close enough to support it.
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The fallacies of presumption occur when the premises presume what they purport to prove. Such
presumptions occur when the arguer creates the illusion that inadequate premises are adequate, asks a
question that masquerades as two or more questions, uses a disjunctive statement that falsely claims to
exhaust the available alternatives, or ignores important evidence that requires a different conclusion.
The fallacies of ambiguity occur when the conclusion depends on some form of linguistic ambiguity.
Either a word or phrase is used in more than one sense or the wrong interpretation is given to an
ambiguous statement.
The fallacies of grammatical analogy occur when a defective argument appears good owing to a
grammatical similarity to some argument that is not fallacious. Such grammatical similarities occur in
arguments that wrongly transfer an attribute from parts to a whole or from a whole to its parts.
Fallacies that occur in real-life argumentation are harder to detect than those in manufactured examples
because they may not exactly fit the structure of the named fallacies and because several fallacies can be
woven together in a single passage.
Three factors that underlie the commission of fallacies in real-life argumentation are the intent of the
arguer, mental carelessness combined with unchecked emotions, and unexamined worldviews.
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