Transcript Logical Fallacies

Logical Fallacies
The Fallacy of Begging the Question: This is a common logical
fallacy. It involves assuming the point that needs to be proven.
In other words, in attempting to prove a point, one assumes the point
that one has set out to prove. One ends up arguing in a vicious circle.
Click the next slide for an example of begging the question -
IE, novelist John Irving writes:
If you expect people to be responsible for their children, then
you have to give them the right to choose whether or not to
have children (abortion).
With that kind of logic, one could argue anything, I.e.,:
"If you expect people to be responsible for their fellow citizens,
you have to give them the right to choose whether or not to pay
income tax."
(
Or, consider the following:
Without the predictive precision of mathematics, any claim to
truth is illusory. If you cannot express your knowledge in
mathematical form, you may know something; you may have the
beginnings of knowledge, but your knowledge is inevitably of a
rudimentary and incomplete form.
* The problem with this is that the statement is not expressed in mathematical form, nor
can it be. Moreover, the author does not prove his point, but only states it.
Or,
All rights should be enshrined in law.
Abortion is a basic human right.
Therefore, abortion should be enshrined in law.
Fallacy of Ignoring the Question: This is the fallacy that consists in
proving something other than the point to be established. It consists in
evading the original issue.
For example, consider the following:
There is an incredible amount of empty space in the universe. The
distance from the sun to the nearest star is about 4.2 light years, or
25 followed by 12 noughts miles...And as to mass: the sun weighs
about 2 followed by 27 noughts tons, the Milky Way weights about
160,000 times as much as the sun and is one of a collection of
galaxies of which, as I said before, about 30 million are known. It is
not very easy to retain a belief in one's own cosmic importance in
view of such overwhelming statistics.
Bertrand Russell
Sophistry (an instance of ignoring the question): a flawed but very
deceptive method of argumentation.
Consider the following debate:
John: “Even the bible does not state that euthanasia is murder. It
states simply: “Thou shalt not kill”. That mercy killing is murder is
your inference.
Bill: “John, my dictionary defines murder as the 'premeditated
killing of one human being by another'.”
John: “Bill, your dictionary has nothing to do with this.”
* Granted, Bill’s dictionary has nothing to do with the debate, since it is probably sitting on his book
shelf collecting dust. But the correct definition of words certainly is relevant to a proper debate. If
John were to say “the true meaning of words has nothing to do with this”, we’d all see him for what he
really is, namely irrational.
“The new budget will be out tomorrow. We plan to oppose the
government and vote against it.”
"Shouldn’t you read the document first, before you come out
publicly against it?"
To which the politician replied: "There’s no virtue in delay”.
* Indeed, delay and virtue seem unrelated. Virtue is a good habit, delay is an
unexpected lapse of time. But it might be wise, nevertheless, to deliberately wait
until all the evidence is in.
Or, consider the following: During a debate on sexual ethics, the person who is arguing against the Catholic
understanding begins to argue,
"The Pope has no business in our bedrooms. Keep the Pope out of my
bedroom."
Or, with regard to the abortion debate,
"Keep your rosaries off my ovaries".
These are forms of the fallacy of Ignoring the Question, for the Pope is
not in anyone's bedroom, nor is the rosary on anyone's ovaries. The
issue is whether or not the sexual act is an expression of conjugal love, or
whether abortion is the destruction of a developing human life. Are these
issues of privacy? One would have to show that they are. But instead of
doing so, he/she employs the fallacy of Ignoring the Question and
formulates excellent sophistry that is also an instance of the fallacy of
Appeal to the People.
The Fallacy of False Cause: This fallacy consists in assuming that
when one event precedes another, it is the cause of the succeeding
event.
“If it were permitted to reason consistently in religious matters, it is
clear that we all ought to become Jews, because Jesus Christ was born
a Jew, lived a Jew, and died a Jew, and because he said that he was
accomplishing and fulfilling the Jewish religion.”
Voltaire
Or,
“Look at all the wars going on in the world. They are all between
different religious factions. The sooner we get rid of religion, the
better off this world will be.”
On the road I travel to the mall in Wheaton, Md., two white men severely
beat two black women Tuesday. One was doused with lighter fluid, and
her attacker tried to set her afire. Both men cursed the women for being
black. I couldn't help but shudder: That could have been me. This
heinous act happened only hours after Pat Buchanan voters gave him 30
percent of the vote in the Maryland GOP presidential primary." — USA
Today columnist and former "Inquiry" page editor Barbara Reynolds,
March 6, 1992
The Fallacy of Accident. This fallacy consists in treating what is
accidental (attribute inhering in a subject) to a subject as something
essential to that subject.
“No, there is only one most sacred human right, and this right is at
the same time the most sacred obligation, namely, to see to it that the
blood is preserved pure, so that by the preservation of the best human
material a possibility is given for a more noble development of these
human beings.”
Hitler
The Fallacy of Part and Whole: This fallacy consists in attributing to a
whole what belongs only to its parts (the fallacy of generalization).
All Muslims are terrorists.
All who with turbans and beards are terrorists.
Or, the fallacy occurs when a person attributes to the part what belongs
only to the whole.
Ie, Since America is such a prosperous nation, all of its citizens must be
well off. Here what belongs only to a whole is predicated of the parts.
On Oprah recently, a so-called “expert” told a couple that they have only
a 50% chance of a successful marriage. Why? Because 50% of all
marriages today end in divorce.
Note:
It is not this fallacy that is politically incorrect. Rather, it is this
fallacy as applied to certain groups of people that is politically
incorrect. For example, today it is politically incorrect to apply
this fallacy to:
• Jews
• Black people
• Homosexuals
But it is politically correct to apply this fallacy to:
• Americans
• Conservatives
• Catholics (clergy)
• Muslims
The Fallacy of Misplaced Authority: It consists in concluding that
something is true because somebody of authority said it. Yet the kind of
authority he or she has and the issue at hand are simply incongruent.
"My doctor assured me that Fords are the best cars. Therefore, I'm going
to buy a Ford. After all, he is a doctor.“
Or,
"Albert Einstein said that criminals are not responsible for their criminal
behaviour, and that such behaviour is a result of ignorance. I'd listen to
Einstein over some unknown psychologist from the University of
Guelph; for who has ever heard of Professor Quigglemyer?“
Or,
Consulting Nobel Prize winners in Chemistry, Physics, and Medicine to
comment on world issues. Or, consulting renowned scientists to
comment on the existence of God.
The Fallacy of Ad Hominem (directed to the man): This involves the
criticism of some person's position or belief by criticizing the person
rather than the position itself.
“Einstein couldn't have been right about Relativity, for just look at the
way he combs his hair.”
“Look at the way he stutters when he talks. He must not know what
he's talking about, so I'm not going to vote for him.”
The Fallacy of the Double Standard: This fallacy consists in applying
one standard for one group or individual, and another standard for an
opposing group or individual.
For example, according to the popular media (predominantly Democrat),
Dan Quayle (a Republican) is not fit to be President of the United States
because he misspelled potato (potatoe).
But Bill Clinton (a Democrat) can commit perjury, adultery, and sexually
abuse a woman young enough to be his daughter and lie about it under
oath, and remain--in the eyes of the liberal media--a good president
because “his private life has nothing to do with his public life.”
The Fallacy of Equivocation: This fallacy occurs when some
word or expression is used with more than one meaning in an
argument. For instance, consider the following argument:
Addicts, who have serious emotional problems, tend to think in
black and white terms, that is, they tend to be absolutists.
John argues that there are absolute moral precepts.
Therefore, John has serious emotional problems.
Or,
It is unreasonable to be so inflexible.
Bill will not compromise (is inflexible) on euthanasia.
Therefore, Bill is unreasonable.
The Fallacy of Appeal to Ignorance: This fallacy
occurs whenever someone argues that a statement is false
because it has not been proved to be true, or is true because it
has not been proved to be false.
With all the effort people have spent trying to show that
people do not communicate with one another through mental
telepathy, no one has succeeded in showing that telepathy
does not occur. That is why we argue that communication
through mental telepathy occurs.
Or, consider the following argument:
Elephants have red eyes so that they can hide in cherry trees.
Have you ever seen an elephant in a cherry tree?
No.
There you go! That proves my point.
Appeal to the People: This fallacy occurs when a speaker attempts
to get some group to agree to a particular position by appealing
solely to their bigotry, biases, and prejudices or, in some cases,
merely to their desire to hear what they already believe.
As an example, consider the last election when the politicians
appealed to the people's fears about medicare and began to accuse the
Alliance Party of advocating a two tiered heath care system. They
were appealing to their prejudices, but they were not engaged in
rational argument.
The Fallacy of False Analogy: This occurs when a person argues a
position merely by drawing an analogy, without justifying the use of
the analogy.
Analogies only illustrate a point, they do not prove a point.
For an example, click to the next slide:
Recently, an Engineer argued the following regarding the issue of
abortion and the status of the fetus. He writes:
The reality is that there is a gradual transition from germ cell to human
being. Is a set of plans a building? Most people would say no, not until
there are foundations, walls, windows, a roof, etc., something
resembling a functional building. A zygote is really nothing but a set of
plans. It has a set of instructions, but nothing else. It will become a
genuine human only after a lot of materials are delivered and
assembled properly.
Not only is the above an instance of begging the question, but an
analogy is employed that is radically false. A living organism is not at
all like an artifact, such as a computer or a building. An organism is a
unified and living whole that has an internal principle of movement. An
artefact is the sum of its parts, a multiplicity of substances--not one
substance--and its principle of movement is not internal, but external,
namely the builders.
Fallacy: Appeal to Novelty
Appeal to Novelty is a fallacy that occurs when it is assumed that
something is better or correct simply because it is new. This sort of
"reasoning" has the following form:
1.X is new.
2.Therefore X is correct or better
Or
Change is an inevitable part of
life.
Therefore, all change is good.
This sort of "reasoning" is fallacious because the
novelty or newness of something does not automatically
make it correct or better than something older.
This sort of "reasoning" is appealing for many reasons.
• First, "western culture" includes a very powerful commitment
to the notion that new things must be better than old things.
• Second, the notion of progress (which seems to have come, in
part, from the notion of evolution) implies that newer things will
be superior to older things.
• Third, media advertising often sends the message that newer
must be better. Because of these three factors (and others) people
often accept that a new thing (idea, product, concept, etc.) must
be better because it is new. Hence, Novelty is a somewhat
common fallacy, especially in advertising.
A professor is lecturing to his class.
Prof: "So you can see that a new and better morality is sweeping the nation.
No longer are people with alternative lifestyles ashamed. No longer are people
caught up in the outmoded moralities of the past."
Student: "Well, what about the ideas of the the great thinkers of the past?
Don't they have some valid points?"
Prof: "A good question. The answer is that they had some valid points in their
own, barbaric times. But those are old, moldy moralities from a time long
gone. Now is a time for new moralities. Progress and all that, you know."
Student: "So would you say that the new moralities are better because they
are newer?"
Prof: "Exactly. Just as the dinosaurs died off to make way for new animals,
the old ideas have to give way for the new ones. And just as humans are better
than dinosaurs, the new ideas are better than the old. So newer is literally
better."
Student: "I see."
Fallacy: Appeal to Ridicule
The Appeal to Ridicule is a fallacy in which ridicule or mockery is
substituted for evidence in an "argument." This line of "reasoning"
has the following form:
X, which is some form of ridicule, is presented (typically directed
at the claim).
Therefore claim C is false (or bad).
The fallacy of Exaggeration
• "Sure my worthy opponent claims that we should lower tuition,
but that is just laughable."
• "Support the ERA? Sure, when the women start paying for the
drinks! Hah! Hah!"
• "Those wacky conservatives! They think a strong military is the
key to peace!"
Remember:
Moral Relativism is rooted in a denial of truth. Since one
cannot reason to truth (since it does not exist), one need not
obey the laws of reasoning, that is, the rules of logic.
That is why in a world in which moral relativism reigns
supreme (such as Canada, Western Europe, and the United
States of the late 20th century), logical fallacies will be
employed in order to “win the argument”. It is okay to be
unreasonable, since reason is impossible anyway.