Informal Fallacies

Question 0

These involve flawed reasoning caused by such things as a misleading emphasis on a word or phrase, shifting meanings of words with an argument, incorrect inferences from parts to wholes – and vice versa.

Answer 0

Fallacies of ambiguity

Question 1

Arguments that look persuasive but are unsound.

Answer 1

Fallacies

Question 2

Arises from faulty grammar such as omission of punctuation marks or incorrect positioning of words or phrases.

Answer 2

Amphiboly

Example: “one morning I shot of elephant in my pyjamas. How we got in my pyjamas I’ll never know.”

Question 3

Arise when words or sentences are taken out of context and given visual or verbal emphasis that they were not meant to have.

Answer 3

The fallacy of Accent

Example: Fly to Australia for $89 – one-way fare, not including tax, surcharges, transfers, etc.

Question 4

Arises when a key term or word in an argument changes meaning during the course of the argument.

Answer 4

The fallacy of equivocation.

Example: A feather is light. Whatever is light cannot be dark. Therefore a feather cannot be dark.

Question 5

Arises when characteristics of a group are inferred from characteristics of its individual parts or members.

Answer 5

The fallacy of composition.

Example: since every human must die, the human race will one day die.

Question 6

Arises by incorrectly inferring characteristics of the individual parts of a set or group from the characteristics of the group as a whole.

Answer 6

The fallacy of division

Example: Cambridge University is a great university and since Sharon went to Cambridge University she must be great to.

Question 7

All such arguments contain unstated assumption that it is flawed. In the most obvious cases, conclusions are arrived on the basis of a single instance.

Answer 7

Fallacies of presumption

Question 8

Any form of argument in which the conclusion appears as one of the premises. Also known as petitio principii, or arguing in a circle.

Answer 8

The fallacy of Begging the question.

Example: we know that the Buddha was enlightened because he said so, and enlightened beings never lie.

Question 9

An argument which is presented with only two alternatives where in reality others may exist. Sometimes known as the “black and white fallacy” or the “excluded middle” it presents an “either…or” situation when there are in fact other options.

Answer 9

The fallacy of bifurcation.

Examples: there are two types of people in the world: the wealthy and the losers. Do you want to be wealthy or a loser?

You either love them or you hate them.

You’re either with me or against me.

Question 10

Incorrectly highlighting the similarity of two things.

Answer 10

The fallacy of false analogy.

Example: a nuclear power plant is safer than eating, because 500 people choke to death on food every year.

Children and adults are similar because they are both human. Adults are allowed to smoke cigarettes. Therefore, children should be allowed to smoke.

Question 11

An argument that suggests events are causally connected when in fact no causal connection has been convincingly established. Post hoc, ergo propter hoc, meaning “after this, therefore because of this”.

Answer 11

The fallacy of false cause.

Examples:
The USSR collapsed after instituting state atheism. Therefore we must not Institute state atheism for the same reasons.

The wealthiest town had the lowest incidence of obesity, well the poorest had the highest. This goes to show that poverty is the cause of obesity.

Question 12

This fallacy occurs with the error of assuming that what is true under certain conditions is true under all conditions.
Also called dicto simpliciter occurs when a general rule is applied to a particular situation in which the features of that particular rule are inapplicable.

Answer 12

The fallacy of sweeping generalisation.

Examples:
Jogging is healthy exercise so Craig should take it up as it will be good for his heart condition.

My parents have told me to always tell the truth so I will tell Aunt Thelma that her new hairstyle looks awful.

Question 13

This fallacy occurs when a generalisation or principle is drawn on the basis of too small a sample or an uncommon case. It may also occur because of laziness or sloppiness. It is very easy to simply leap to a conclusion; much harder to gather an adequate sample and draw a justified conclusion.

Answer 13

The fallacy of hasty generalisation.

Examples:
I’ll never trust another Australian because it was an Australian who stole my watch when I left it in the changing room.

Question 14

This fallacy consists of objecting to something on the grounds of the unwarranted assumption that it will ultimately lead to a bad consequence that in turn will lead to another bad inconsequence and so on. It claims that we must stop the first action in order to prevent the catastrophic slide.

Answer 14

The fallacy of the slippery slope.

Examples:
If I make an exception for you then I have to make an exception for everyone.

Pornography should not be banned. Once they’ve banned one form of literature, it will never stop. Next thing you know, they will be burning all types of books.

Question 15

This fallacy occurs when an opponent’s views are misrepresented and weakened in order to make it easier to criticise. The idea behind the name of this fallacy is that instead of engaging in debate with your real opponent you set up a position not held by your opponent, and then set about destroying the argument as if it were your opponent’s.

Answer 15

The straw man fallacy.

Examples:
Some members of parliament say that the air force should not purchase any more fighter aircraft. I disagree entirely. I can’t understand why they would want to leave us totally defenceless like that.

Question 16

Fallacies that depend upon evidence that’s beside the point and therefore irrelevant. When we assess arguments that commit this type of fallacy we notice that there is a gap in the reasoning. Aside from involving irrelevant considerations, these arguments may also use an illegitimate appeal of one sort or another.

Answer 16

Fallacies of relevance

Question 17

Also known as the fallacy of arguing against the person, it involves attacking an opponent rather than the opponents argument. In it’s crudest form it amounts to nothing more than using insults and mudslinging. This fallacy my also occur when an opponent’s personal or professional standing is used as a reason for discounting an argument. These arguments are fallacious because the personal qualities and beliefs of the arguer are irrelevant to the truth or falsity of the argument that is being presented.

Answer 17

Ad hominem (literally argument to the man)

Examples:
What do you know about the conflict in Ireland; after all you’ve never even been there.

The theory of relativity must be false because its creator, Albert Einstein was Jewish.

Question 18

This fallacy claims that the argument is poor because the arguer doesn’t follow their own advice.

Answer 18

Tu quoque (literally “you also” – best understood as “look who’s talking”)

Examples:
Who are you to say I should stop doing over time? You put in more hours than I do.

You tell me to get more exercise but all you do is sit in your armchair and watch TV all day.

Question 19

This fallacy occurs when the authority been cited has no special knowledge about the topic being argued. This often appears convincing because of appeals to our sense of modesty and our reluctance to argue against the famous person or widely held belief.

Answer 19

Appeal to authority.

Examples:
David Hume was a great philosopher and he liked eggs for breakfast so they must be good for you.

Reverse appeal to authority – I can’t take vegetarianism seriously because Hitler was a vegetarian.

Question 20

This fallacy attempts to persuade by appealing to popular opinion and mass sentiment.

Answer 20

Appeal to the masses.

Examples:
All my friends are going so I should be allowed to go too.

The cool kids of our age smoke cigarettes; you should too.

Question 21

Also known as “scare tactics” Or “swinging the big stick” this fallacy occurs when, instead of using good reasoning, force is used to persuade. Examples may include verbal or sexual harassment, blackmail, extortion, bribery, or physical force.

Answer 21

Appeal to force. (Argumentum ad baculum)

Examples:
You should believe in God because if you don’t you will be punished and sent to hell. You don’t want to spend an eternity being tortured in hell do you?

I say to the members of the jury, if you don’t convict the defendant of this heinous crime then, dare I say it, one of your children may be their next victim.

Question 22

This fallacy is used as a technique to try to bypass a persons thinking abilities. An irrelevant appeal is made to encourage us to respond with pity and except the conclusion given.

Answer 22

Appeal to pity. (Ad misericordiam - Latin meaning “appeal to sympathy or compassion”)

Examples:
The defendant should not be found guilty of murder, since it would break his poor mothers heart to see him sent to jail.

I know I can do the job that you have advertised, and I really need to find work soon as my mother is sick and I need money to pay the hospital bills.

Question 23

This fallacy arises when someone argues that because we do not know that a certain statement is true then it must be false. This argument takes the form of: “if you can’t prove me wrong, then I must be right.”

Answer 23

Appeal to ignorance. (Argumentum ad ignoratum)

Examples:
You can’t prove that God does not exist, therefore, God exists.

There is insufficient evidence to show that God exists. Therefore, God does not exist.