Logical Fallacies

Topics: Logic, Deductive reasoning, Argument Pages: 5 (1268 words) Published: November 8, 2009
Logic
An argument consists of one or more premises and one conclusion. A premise is a statement that can be either true or false that is offered to support a claim. The claim is the conclusion that can be either true or false. Arguments can be deductive or inductive. Deductive vs. Inductive

A deductive argument is an argument in which the premises appear to provide complete support for the conclusion. An inductive argument is an argument such that the premises appear to provide some degree of support for the conclusion. If the premises actually provide the required degree of support for the conclusion, then the argument is a good one. A good deductive argument is a valid argument and is such that if all its premises are true, then its conclusion must be true. If all the argument is valid and actually has all true premises, then it is known as a sound argument. If it is invalid or has one or more false premises, it will be unsound. A good inductive argument is such that if the premises are true, the conclusion is likely to be true. In inductive reasoning, the premises may predict a high probability of the conclusion, but they do not ensure that the conclusion is true Fallacies

Logical fallacies are arguments based on faulty reasoning. They often appear true at first, but they do not remain viable under scrutiny. A fallacy is an “argument” in which the premises given for the conclusion do not provide the needed degree of support. A deductive fallacy is a deductive argument that is invalid (it is such that it could have all true premises and still have a false conclusion). An inductive fallacy is less formal than a deductive fallacy. They are arguments which appear to be inductive arguments, but the premises do not provided enough support for the conclusion. In such cases, even if the premises were true, the conclusion would not be more likely to be true.

Logic
Argument: Premises and Conclusion

Deductive vs. Inductive Logic and Fallacies

1.Deductive argument is an argument in which the premises appear to provide complete support for the conclusion. 2.Inductive argument is an argument such that the premises appear to provide some degree of support for the conclusion. 3.A deductive fallacy is a deductive argument that is invalid (it is such that it could have all true premises and still have a false conclusion). 4.An inductive fallacy is less formal argument which appears to be an inductive argument, but the premises do not provided enough support for the conclusion. In such cases, even if the premises were true, the conclusion would not be more likely to be true.

Examples of Fallacies

I.Deductive Argument
a.The law must treat all men as equal.
b.Ian and Tim are men.
c.The law must treat Ian and Tim equally.

II.Inductive Argument
a.Premise 1: Most American cats are domestic house cats.
b.Premise 2: Bill is an American cat.
c.Conclusion: Bill is domestic house cat.

III.Factual Error
a.New York City is the capital of the United States.

IV.Deductive Fallacy
a.Premise 1: If Elkton is the capital of Maryland, then it is in Maryland. b.Premise 2: Elkton is in Maryland.
c.Conclusion: Elkton is the capital of Maryland.

V.Inductive Fallacy
a.Premise: Having arrived at Paul’s house, I had a delicious piece of homemade Baklava. b.Conclusion: Paul makes delicious desserts.
Common Logical Fallacies:

Ad Hominem Attack / Poisoning the Well: Unfavorable information (be it true or false) about person A is presented; therefore any claims person A makes will be false. (An attack on a person rather than on his or her ideas) Ex: The Speaker of the House reminded Congress that George Bush “didn’t speak Mexican” before they voted on a border patrol bill.

Generalization: conclusion based upon inadequate data
Ex: In a study of motorists in Cecil County who own Saabs, two of the six had faulty transmissions; therefore, the Saab is a lousy car.

Anecdotal Evidence:...