Chapter 6

Validity

A deductive argument is valid if the two premises are correctly, that is, logically, constructed, and the conclusion follows logically.

False Analogy

A false analogy is noting many differences in the two items being compared or by noting a significant difference that has been ignored.

Forced Hypothesis

A forced hypothesis is also an error in inductive reasoning. The hypothesis offered is "forced" or illogical because either 1. sufficient evidence doesn't exist to draw any conclusion or 2. the evidence can be explained more simply or more sensibly by a different hypothesis.

Slippery Slope

A slippery slope argument asserts that we should not proceed with or permit A because, if we do, the terrible consequences X, Y, and Z will occur. This type of argument oversimplified by assuming without evidence.

A. All people who perform with courage and a clear purpose in a crisis are great leaders. B. Lincoln was a person who performed with courage and a clear purpose in a crisis. C. Lincoln was a great leader. Which letter is the major premise, the minor premise and the conclusion?

A. Major Premise B. Minor premise C. Conclusion

Analogy

Analogies assert that since A and B are alike in several ways, they must be alike in another way as well.

Begging the Question

Begging the question is assuming that part of your argument is true without supporting it.

Deduction

Deduction is the reasoning process that draws the conclusion from the logical relationship of two assertions, usually one broad judgement or definition and one more specific assertion, often an inference.

A. All people who perform with courage and a clear purpose in a crisis are great leaders. B. Lincoln was a person who performed with courage and a clear purpose in a crisis. C. Lincoln was a great leader. Is this an example of an inductive or deductive reasoning?

Deductive Reasoning

Hasty or Faulty Generalizations

Hasty or faulty generalizations may be qualified assertions, but they still oversimplify by arguing from insufficient evidence or by ignoring some relevant evidence.

Induction

Induction is the process by which we reach inferences- opinions based on facts or on a combination of facts and less debatable inferences.

Claim: Dinosaurs were the dominant life form during the Mesozoic era. Grounds: Facts presented from a source. Assumption: The facts are representative, revealing dinosaur diversity. Is this an example of inductive or deductive reasoning?

Inductive Reasoning

Premises

Premises are the two reasons of an deductive argument.

If we allow the government to register handguns, next it will register hunting rifles; then it will prohibit all citizen ownership of guns, thereby creating a police state or a world where only outlaws have guns. What sort of logical fallacy is this?

Slippery Slope

Ad Hominem

The ad hominem argument, literally "to the man," appeals to emotion masquerading as argument.

Ad Populum

The ad populum technique, literally "to the people," arouses an audience's emotion and ignores the issue. This argument appeals to the audience's presumed shared values and beliefs.

Argument from Analogy

The argument from analogy is an argument based on comparison.

Common Practice or Band Wagon

The band wagon argument is arguing that an action should be taken or position accepted because everyone is doing it. This argument is illogical; the majority is not always right.

False Dilemma

The false dilemma oversimplifies by asserting only two alternatives when there are more than two.

Major Premise

The major premise is the broader premise in a deductive argument.

Minor Premise

The minor premise is the more specific premise in a deductive argument.

Red Herring

The red-herring introduces a side issue, some point that is not relevant to the debate.

Straw Man

The straw man argument attributes to opponents incorrect and usually ridiculous views that they do not hold so that their position can be easily attacked.

Non Sequitur

The term non sequitur, meaning literally "it does not follow," could apply to all illogical arguments, but the term is usually reserved for those in which the conclusions are not logically connected to the reasons.

Post Hoc Fallacy

The term post hoc, literally, "after this, therefore because of it," refers to a common error in arguments about cause.