Logical Fallacies

A logical fallacy is a predictable flaw or fault that help people

assess the soundness of an argument. Fallacies try to convince you of

something without actually proving any reason to accept the

conclusion. They can happen accidentally, but sometimes people use

them on purpose to manipulate others. There are two types of logical

fallacies. Formal fallacies are known as "structural errors in deductive

logic" (Textbook). This means the syllogism would be invalid. An

informal fallacy is one that "persuades by means other than reason".

For example, look at the article by Keith Gilligan in the April 2,

2008 Ajax News Advertiser, titled "Ajax wants to hear from residents

on corporate strategy". This, is a type of Fallacy of Ambiguity

(incorrect reasoning rising from the imprecise use of language), known

as an amphiboly. A Fallacy of Amphiboly happens when the

construction of a sentence creates ambiguity. For example, "Most

stores carry jeans for people with 32 waists". This statement could be

taken either of two ways. Either most stores carry jeans for people

that have thirty two different waists, or, most stores carry jeans for

people that have size thirty-two waists. Now lets look at the News

Advertisers Fallacy of Amphiboly, "Ajax wants to hear from residents

on corporate strategy". This could either mean that Ajax wants to

hear from residents about their corporate strategy, or it could mean

that Ajax wants to hear from residents that are on top of the corporate

strategy. The way the sentence is constructed makes it difficult to

figure out which meaning was being implied, because the language

used was not precise enough. Another example of Amphiboly is when

the author opens the article by saying "Two open houses are being

held next month..." Does Keith Gilligan mean that someone is going

to hold two houses that are open, in their hands? Or does he mean

that there will be a house, open for visitation, at two separate times

during the month? More precise language would make the intended

meaning much easier to derive.

Another kind of fallacy is a Fallacy of Relevance. A Fallacy of

Relevance is a fallacy that provides no real support for the conclusion.

One type of fallacy of relevance that is evident in Keith Gilligan's article

is Appeal to Force. This happens when someone who is in charge, or

in power, makes statements to force a conclusion. For example, a

teacher may say "I am the teacher, and I say that Kim Campbell was

Canada's best prime minister ever, so Kin Campbell must be Canada's

best prime minister ever." In the News Advertisers article, a very

obvious example of this is when Marilou Murray, the assistant to Chief

Administrator Officer says "We're moving along well". This is an

example of Appeal to Force because since Marilou Murray is in a

position of power, she can claim that the new strategy is working well,