Philosophy 103 - Introduction to Logic: Critical Thinking
2/9 - Informal Fallacies III
a.k.a Revenge of the Fallacy; Son Of Fallacy, Bride of Fallacy etc.
1. Begging the Question:
This can occur in several different forms. Essentially, this fallacy occurs when the key premise of an argument is unsupported. Here are some varieties of this common fallacy:
Circular reasoning: Murders have lost the right to live because anyone who takes the like of another person has given up that right.
Concealed Premise: Murder is always wrong. Therefore, the death penalty is wrong. (The concealed premise: The death penalty is murder).
Wishful Thinking: Of course there is life after death; if I didn't believe that, life would be too depressing.
2. Complex Question:
Sometimes called a "loaded question". A question which contains a hidden assumption or condition. Often, complex questions are such that no matter how you answer them, you may be acknowledging something you might not want to acknowledge.
Examples: When did you stop lying to your friends? When are you going to give up being a Nazi?
3. False Dichotomy or False Dilemma:
Presents as a premise two alternatives as if they were the only two available when in fact there are more. Often the conclusion is only implied and not stated.
Example: Either we elect Mr. X or the economy goes down the tubes. The choice should be obvious.
The way to avoid falling into this trap: before you accept X because Y is false, make sure there isn't some other alternative that allows you to reject X as well.
4. Suppressed Evidence:
An inductive argument which ignores overriding evidence which would prove a different conclusion.
This is common is advertising. Example: Rent-to-own: the cheaper way to buy!
Quoting out of context can also lead to this fallacy, as can ignoring current events.
Where the conclusion of the argument depends on the fact that a word is being used in two different senses due too semantic ambiguity.
Example: Everyone wants to do what is right. Therefore, you have the right to do what you want.
A sentence is ambiguous when it has two or more meanings (note: ambiguity and vagueness are two different things. Vague means imprecise). Semantic ambiguity is the result of one word having two or more definitions.
Example: The banks were important to the town.
Where the conclusion of the argument depends on the fact that a sentence is syntactically ambiguous.
Example: Norris said he operates a small car repair shop. Therefore, you can't take your Cadillac to him. This can be a real problem in legal documents.
A sentence is syntactically ambiguous when the grammar of the sentence allows for more than one interpretation of its meaning.
Example: John attacked the man with a knife.
Mistaking properties of the parts for properties of the whole.
Example: Every member of the team is a winner; therefore the team is a winner.
Not every instance of this type of reasoning is bad however.
Example: Each one of these stamps is valuable. Therefore, the collection of stamps as a whole is valuable.
Here is another example:
HAGAR THE HORRIBLE
by Chris Browne
© 1990 King Features Syndicate Inc. World rights reserved.
Mistaking properties of the whole for properties of the parts.
Example: This wooden table is made up of smaller things called atoms. Since the table is wooden, its atoms must be wooden too. Or: This team is the best in the conference; therefore each team member must be the best in the conference.
Again, not every instance of this reasoning is bad. Pay attention to the context and the details.