2. 1. A fallacy is an error in reasoning—a type of
argument that may seem to be correct, but proves not
to be so upon closer examination.
An argument is said to commit a fallacy when it makes
a mistake of a given type.
There are four main categories of logical fallacies:
(1)fallacies of relevance, (2) defective induction,
(3)presumption, and (4)ambiguity.
Within these four subcategories, this chapter covers 17
different logical fallacies.
3. Fallacies of relevance rely on premises that seem to be
relevant to the conclusion when, in fact, they are not.
There are six major fallacies of relevance:
1. Appeals to emotion
2. Red herring
3. Straw man
4. Argument ad hominem
5. Appeal to force
6. Missing the point (irrelevant conclusion)
4. Also called ad populum (to the populace)
The most obvious of all fallacies
Yet also the most common error made
It appeals to the emotions of the audience
http://www.youtube.com/watch?v=1eMmcMK_3Ao
It is used by advertising, politicians, propaganda
The speaker relies on expressive language and other devices
to excite the audience for their cause or against another –
rather than to use rational argument and evidence
Choice of words that cause an emotive response
Also ad misercordiam – appeal to pity or mercy
http://www.youtube.com/watch?v=gV9AGwwos0E
5. "Pornography must be banned. It is violence against
women."
"For thousands of years people have believed in Jesus
and the Bible. This belief has had a great impact on
their lives. What more evidence do you need that Jesus
was the Son of God? Are you trying to tell those people
that they are all mistaken fools?"
6. The fallacy that relies on distraction
Attention is deflected away from the topic being
argued or discussed and focused on another area that
is related to the topic (or not) but irrelevant to the
point being argued
Any deliberately misleading trail is called a red herring
http://www.youtube.com/watch?v=mnJjLsq9abE
http://www.youtube.com/watch?v=exdK7Lirngg&feat
ure=related
7. This fallacy is committed when someone introduces
irrelevant material to the issue being discussed, so that
everyone's attention is diverted away from the points
made, towards a different conclusion.
"You may claim that the death penalty is an ineffective
deterrent against crime--but what about the victims of
crime? How do you think surviving family members
feel when they see the man who murdered their son
kept in prison at their expense? Is it right that they
should pay for their son's murderer to be fed and
housed?"
8. Arguing the opponent’s view as one that is easily torn
apart (made of straw)
It is similar to red herring in that it distracts from the
real argument by placing words or entire arguments
that were never made or said
Key words for this : all, every, none, never and of
course… “the man” (the government, big brother, etc)
YouTube - The "Straw Man" Fallacy
9. The straw man fallacy is when you misrepresent
someone else's position so that it can be attacked more
easily, knock down that misrepresented position, then
conclude that the original position has been
demolished. It's a fallacy because it fails to deal with
the actual arguments that have been made.
"To be an atheist, you have to believe with absolute
certainty that there is no God. In order to convince
yourself with absolute certainty, you must examine all
the Universe and all the places where God could
possibly be. Since you obviously haven't, your position
is indefensible."
10. Also called ad hominem (to the man)
The most irrational and morally wrong of the fallacies
Often hurtful and attempting personal damage of the
person
The argument shifts away from the topic and becomes an
attack on the person instead
Two major types : abusive and circumstantial
Abusive – attempts to disparage the character of the other
directly; insult
Circumstantial – attacking what a person does, or did, or
their affiliation, etc.
http://www.youtube.com/watch?v=k58IkX_MqpA
11. Argumentum ad hominem literally means "argument directed at the man"; there are two
varieties.
The first is the abusive form. If you refuse to accept a statement, and justify your refusal
by criticizing the person who made the statement, then you are guilty of abusive
argumentum ad hominem. For example:
"You claim that atheists can be moral--yet I happen to know that you abandoned your
wife and children."
This is a fallacy because the truth of an assertion doesn't depend on the virtues of the
person asserting it. A less blatant argumentum ad hominem is to reject a proposition
based on the fact that it was also asserted by some other easily criticized person. For
example:
"Therefore we should close down the church? Hitler and Stalin would have agreed with
you."
A second form of argumentum ad hominem is to try and persuade someone to accept a
statement you make, by referring to that person's particular circumstances. For example:
"Therefore it is perfectly acceptable to kill animals for food. I hope you won't argue
otherwise, given that you're quite happy to wear leather shoes."
This is known as circumstantial argumentum ad hominem. The fallacy can also be used
as an excuse to reject a particular conclusion. For example:
"Of course you'd argue that positive discrimination is a bad thing. You're white."
This particular form of Argumentum ad Hominem, when you allege that someone is
rationalizing a conclusion for selfish reasons, is also known as "poisoning the well."
12. Also called ad baculum (to the stick)
Using threats or strong arm methods to win the
argument rather than to discuss it
http://www.youtube.com/watch?v=kM7xsmJFDEM
13. An Appeal to Force happens when someone resorts to
force (or the threat of force) to try and push others to
accept a conclusion. This fallacy is often used by
politicians, and can be summarized as "might makes
right." The threat doesn't have to come directly from
the person arguing. For example:
"Thus there is ample proof of the truth of the Bible. All
those who refuse to accept that truth will burn in
Hell."
"In any case, I know your phone number and I know
where you live. Have I mentioned I am licensed to
carry concealed weapons?"
14. Also called ignoratio elenchi (mistaken refutation)
This happens when an argument goes off track, a
disconnect occurs somewhere along the way and the
‘point is missed’
Usually the cause of faulty logic and poor rationing
ability
Frequently occurs when one does not understand the
proposition in dispute
Exercises p.135 – 141
15. The fallacy of Irrelevant Conclusion consists of claiming
that an argument supports a particular conclusion when it
is actually logically nothing to do with that conclusion.
For example, a Christian may begin by saying that he will
argue that the teachings of Christianity are undoubtedly
true. If he then argues at length that Christianity is of great
help to many people, no matter how well he argues he will
not have shown that Christian teachings are true.
Sadly, these kinds of irrelevant arguments are often
successful, because they make people to view the supposed
conclusion in a more favorable light.
16. Fallacies of defective induction arise from the fact that
the premises of the argument, although relevant to the
conclusion, are so weak and ineffective that reliance
upon them is a blunder. We will cover these 4 major
ones:
1. Arguments from ignorance
2. The appeal to inappropriate authority
3. False cause
4. Hasty generalization/converse accident
17. Also called ad ignorantium (to ignorance)
If something is not proven true, then it must be false
That we are ignorant to the truth , means it must be
false
An informal fallacy in which a conclusion is supported
by an illegitimate appeal to ignorance (lack of knowing
as true), as when it is supposed that something is likely
to be true because we cannot prove it is false
http://www.youtube.com/watch?v=XyA8cIzosFU
18. Argumentum ad ignorantiam means "argument from ignorance." The fallacy occurs
when it's argued that something must be true, simply because it hasn't been proved false.
Or, equivalently, when it is argued that something must be false because it hasn't been
proved true.
(Note that this isn't the same as assuming something is false until it has been proved
true. In law, for example, you're generally assumed innocent until proven guilty.)
Here are a couple of examples:
"Of course the Bible is true. Nobody can prove otherwise."
"Of course telepathy and other psychic phenomena do not exist. Nobody has shown any
proof that they are real."
In scientific investigation, if it is known that an event would produce certain evidence of
its having occurred, the absence of such evidence can validly be used to infer that the
event didn't occur. It does not prove it with certainty, however.
For example:
"A flood as described in the Bible would require an enormous volume of water to be
present on the earth. The earth doesn't have a tenth as much water, even if we count that
which is frozen into ice at the poles. Therefore no such flood occurred."
It is, of course, possible that some unknown process occurred to remove the water. Good
science would then demand a plausible testable theory to explain how it vanished.
19. Also called ad verecundiam ( to the respected one)
Using the example of an expert or an authority figure
(mom, priest, teacher) to prove your argument is valid
An informal fallacy in which the appeal to authority is
illegitimate because the authority appealed to has no
special claim to expertise on the matter in question
http://www.youtube.com/watch?v=otjRLqSl9Yc
http://www.youtube.com/watch?v=k7zT4m0MYjA&fe
ature=related
20. The Appeal to Authority uses admiration of a famous person to try and
win support for an assertion. For example:
"Isaac Newton was a genius and he believed in God."
This line of argument isn't always completely bogus when used in an
inductive argument; for example, it may be relevant to refer to a widely-
regarded authority in a particular field, if you're discussing that
subject. For example, we can distinguish quite clearly between:
"Hawking has concluded that black holes give off radiation"
and
"Penrose has concluded that it is impossible to build an intelligent
computer"
Hawking is a physicist, and so we can reasonably expect his opinions on
black hole radiation to be informed. Penrose is a mathematician, so it
is questionable whether he is well-qualified to speak on the subject of
machine intelligence.
21. Also called non causa pro causa (non cause for cause)
Attempting to link a cause and effect relationship that is
not really there
An informal fallacy in which the mistake arises from
accepting as the cause of an event what is not really the
cause
A variety of this is the post hoc ergo hoc (after the thing,
therefore because of the thing) – just because something
happened does not mean it caused another thing that may
be unrelated to it
http://www.youtube.com/watch?v=TZ7UMOV9UMA&p=B
62092A0ED907098&playnext=1&index=13
22. The fallacy of Non Causa Pro Causa occurs when
something is identified as the cause of an event, but it has
not actually been shown to be the cause. For example:
"I took an aspirin and prayed to God, and my headache
disappeared. So God cured me of the headache.“
The fallacy of Post Hoc Ergo Propter Hoc occurs when
something is assumed to be the cause of an event merely
because it happened before that event. For example:
"The Soviet Union collapsed after instituting state atheism.
Therefore we must avoid atheism for the same reasons.“
http://www.youtube.com/watch?v=THzJilpGr7w&feature=
related
23. When we draw conclusions all persons or things in a
given class on the basis of our knowledge of one or a
few
The informal fallacy in which a principle that is true of
a particular case is applied, carelessly or deliberately, to
the majority of other cases
http://www.youtube.com/watch?v=AMzufTogzl0&feat
ure=related
http://www.youtube.com/watch?v=ZgmNSg-
g5GY&feature=fvw
24. Bill: "You know, those feminists all hate men."
Joe: "Really?"
Bill: "Yeah. I was in my philosophy class the other day and that Rachel
chick gave a presentation."
Joe: "Which Rachel?"
Bill: "You know her. She's the one that runs that feminist group over at
the Women's Center. She said that men are all sexist pigs. I asked her
why she believed this and she said that her last few boyfriends were
real sexist pigs. "
Joe: "That doesn't sound like a good reason to believe that all of us are
pigs."
Bill: "That was what I said."
Joe: "What did she say?"
Bill: "She said that she had seen enough of men to know we are all pigs.
She obviously hates all men."
Joe: "So you think all feminists are like her?"
Bill: "Sure. They all hate men."
25. Fallacies of presumption arise when an argument relies
on a proposition that is assumed to be true, but is in
fact false, dubious, or without warrant. There are three
such fallacies:
1. Accident
2. Complex question
3. Begging the question
26. Moving from a generalization to a specific
An informal fallacy in which a generalization is
applied to individual cases that it does not govern (not
related to)
http://www.youtube.com/watch?v=JyVZp5CzaVQ
27. A sweeping generalization occurs when a general rule
is applied to a particular situation, but the features of
that particular situation mean the rule is inapplicable.
It's the error made when you go from the general to the
specific. For example:
"Christians generally dislike atheists. You are a
Christian, so you must dislike atheists."
This fallacy is often committed by people who try to
decide moral and legal questions by mechanically
applying general rules.
28. Rhetorical questions that include the
conclusion/answer already in them
An informal fallacy in which a question is asked in
such a way as to presuppose the truth of some
proposition buried in the question itself
http://www.youtube.com/watch?v=Nh0pePhc5d0
http://www.youtube.com/watch?v=ZsoMIbXfA0g
29. One example is the classic loaded question:
"Have you stopped beating your wife?"
The question presupposes a definite answer to another question
which has not even been asked. This trick is often used by
lawyers in cross-examination, when they ask questions like:
"Where did you hide the money you stole?"
Similarly, politicians often ask loaded questions such as:
"How long will this EU interference in our affairs be allowed to
continue?"
or
"Does the Chancellor plan two more years of ruinous
privatization?"
Another form of this fallacy is to ask for an explanation of
something which is untrue or not yet established.
30. Also called petitio principii (assuming the initial
point)
The proof of the argument is in its own point
An informal fallacy in which the conclusion of an
argument is stated or assumed in one of the premises
http://www.youtube.com/watch?v=1XaEzsP5Iow
Exer. P. 155-157
31. This fallacy occurs when the premises are at least as
questionable as the conclusion reached. Typically the
premises of the argument implicitly assume the result
which the argument purports to prove, in a disguised form.
For example:
"The Bible is the word of God. The word of God cannot be
doubted, and the Bible states that the Bible is true.
Therefore the Bible must be true.
"Homosexuals must not be allowed to hold government
office. Hence any government official who is revealed to be
a homosexual will lose his job. Therefore homosexuals will
do anything to hide their secret, and will be open to
blackmail. Therefore homosexuals cannot be allowed to
hold government office."
32. Fallacies of ambiguity (called sophisms)occur when
arguments are formulated such that they rely on shifts
in the meaning of words from their premises to their
conclusions. Such ambiguous language results in five
fallacies of ambiguity:
1. Equivocation
2. Amphiboly
3. Accent
4. Composition
5. Division
33. Using words other meanings intentionally to distort an
argument
An informal fallacy in which two or more meanings of
the same word or phrase have been confused
intentionally or accidentally
http://www.youtube.com/watch?v=MmhhYcJirl8
http://www.youtube.com/watch?v=1x8V0qY0Dl4
34. Equivocation occurs when a key word is used with two
or more different meanings in the same argument. For
example:
"What could be more affordable than free software?
But to make sure that it remains free, that users can do
what they like with it, we must place a license on it to
make sure that will always be freely redistributable."
One way to avoid this fallacy is to choose your
terminology carefully before beginning the argument,
and avoid words like "free" which have many
meanings.
35. Ambiguous premises because of grammatical issues
An informal fallacy arising from the loose, awkward, or
mistaken way in which words are combined, leading to
alternative possible meanings of a statement.
http://www.youtube.com/watch?v=qQnCS94Zs7E&fea
ture=related
36. Amphiboly occurs when the premises used in an argument are
ambiguous because of careless or ungrammatical phrasing. For
example:
"Premise: Belief in God fills a much-needed gap."
Furnished Apartments for Rent: 3 rooms, river view, private
phone, bath, kitchen, utilities included
Your interest is aroused. But when you visit the apartment, there
is neither a bathroom nor a kitchen. You challenge the landlord.
He remarks that there are common bathroom and kitchen
facilities at the end of the hall. 'But what about the private bath
and kitchen that the ad mentioned?' you query. 'What are you
talking about?' the landlord replies. 'The ad didn't say anything
about a private bath or a private kitchen. All the ad said was
private phone.' The advertisement was amphibolous
37. Changing the emphasis on certain words or phrases to
distort the meaning
An informal fallacy committed when a term or phrase
has a meaning in the conclusion of an argument
different from its meaning in one of the premises, the
difference arising chiefly from a change in emphasis
given to the words used.
http://www.youtube.com/watch?v=CwGEOP0LYfg
38. Accent is a form of fallacy through shifting meaning.
In this case, the meaning is changed by altering which
parts of a statement are emphasized. For example:
"We should not speak ill of our friends"
and
"We should not speak ill of our friends"
Be particularly wary of this fallacy on the net, where
it's easy to misread the emphasis of what's written.
39. Two types:
(1) Reasoning fallaciously from the attributes of the parts of
a whole to the attributes of the whole itself – because a part
means or is one thing then the whole thing exhibits those
same qualities
(2) Reasoning from attributes of the individual elements or
members of a collection to attributes of the collection or
totality of those elements – because elements/members
have an attribute the whole thing/membership has the
same issue.
An informal fallacy in which an inference is mistakenly
drawn from the attributes of the parts of a whole to the
attributes of the whole itself.
http://www.youtube.com/watch?v=xj8QxRDHzlo
40. The Fallacy of Composition is to conclude that a property shared by a number
of individual items, is also shared by a collection of those items; or that a
property of the parts of an object, must also be a property of the whole thing.
Examples:
"The bicycle is made entirely of low mass components, and is therefore very
lightweight."
"A car uses less petrochemicals and causes less pollution than a bus. Therefore
cars are less environmentally damaging than buses."
A related form of fallacy of composition is the "just" fallacy, or fallacy of
mediocrity. This is the fallacy that assumes that any given member of a set must
be limited to the attributes that are held in common with all the other
members of the set. Example:
"Humans are just animals, so we should not concern ourselves with justice; we
should just obey the law of the jungle."
Here the fallacy is to reason that because we are animals, we can have only
properties which animals have; that nothing can distinguish us as a special
case.
41. Two types:
(1) Arguing fallaciously that what is true of a whole must
also be true of its parts - because something is true of a
whole then it is true with all that whole’s parts
(2) When one argues from the attributes of a collection of
elements to the attributes and elements themselves – the
collection is given the same value of its individual elements
An informal fallacy in which a mistaken inference is drawn
from the attributes of a whole to the attributes of the parts
of that whole.
http://www.youtube.com/watch?v=_qBDZxZq-
zM&feature=related
Exer. P. 167-173
42. The fallacy of division is the opposite of the fallacy of
composition. It consists of assuming that a property of
some thing must apply to its parts; or that a property
of a collection of items is shared by each item.
"You are studying at a rich college. Therefore you must
be rich."
"Ants can destroy a tree. Therefore this ant can destroy
a tree."
44. 1. What do the fallacies of relevance have in common? Choose
three of them and discuss how, though they are distinct, they
share this common thread.
2. Why are ad hominem arguments usually made? Are such
arguments ever valid? Explain.
3. How does the argument ad populum differ from just using
emotive language to persuade?
4. One of the most common logical fallacies is that of begging
the question. Think of some examples of this fallacy, and discuss
how they assume what they seek to prove.
5. The fallacy of accent is common in advertising. Take some
examples of advertisements from the media and identify
examples of this fallacy, showing how they suggest their
misleading misinterpretations.
45. 1. What are the distinctions between fallacies of accent,
equivocation, and amphiboly? Using examples of each,
explain how these fallacies are distinct.
2. What do the fallacies of false cause and accident have in
common? Are they really the same fallacy, are they entirely
distinct, or are they related in some, but not all ways?
Explain your answer by giving an example of each.
3. At first glance, composition and division may seem to be
the same as accident and converse accident. However, they
are entirely different. Explain what the real difference is
between these pairs of fallacies.
46. 4. Is arousing emotional responses in an argument always a fallacy? For
example, some charities use stirring appeals to rouse our pity. Are such
arguments the fallacy of “appeal to pity?”What about references to prestigious
individuals, such as well-known experts— aren’t those passages cases of
“appeal to inappropriate authority?” Be sure to use examples to back up your
essay’s claims.
5. Examine the following passage for fallacies, and write an essay describing any
fallacious reasoning you detect in it: “Some people say the reasons to transplant
organs, such as the heart and liver, from one human to another are obvious.
However, I don’t think so. People have vastly different religious and cultural
beliefs, and may attribute spiritual significance to certain organs. Terrible
psychological damage could occur, for instance, if a person were to receive the
heart of a person regarded in that culture as having bad moral character.
Moreover, there are other psychological problems to consider. In the case of
ovary transplants, any woman willing to subject herself to this dangerous
procedure must have an abnormal desire to produce children from her own
body. Should society contribute to these psychological problems by allowing
organ transplants?”
