fallcies of logic
Chapter 5: Logical Fallacies
1. Understanding Arguments and Fallacies
Arguments are prevalent in daily life: books, ads, TV, speeches, discussions.
Sound arguments are convincing; fallacious arguments contain mistakes in reasoning.
Definition: A logical fallacy, or simply a fallacy, is an argument with a mistake in reasoning.
Fallacies are classified into two groups:
Fallacies of Relevance: Premises irrelevant to the conclusion.
Fallacies of Insufficient Evidence: Premises relevant but lack enough evidence to support the conclusion.
2. Concept of Relevance
Relevance: A statement is relevant if it provides a reason to consider another statement true/false.
Types of relevance:
Positively Relevant: Counts in favor of the conclusion.
Negatively Relevant: Counts against the conclusion.
Logically Irrelevant: Does not support or undermine the conclusion.
3. Fallacies of Relevance
3.1 Personal Attack (Ad Hominem)
Definition: Rejecting an argument by attacking the person instead of the argument.
Example: Dismissing Hugh Hefner's arguments against censorship by attacking his character instead.
3.2 Attacking the Motive
Definition: Criticizing the motivation of a person arguing instead of evaluating the argument itself.
Example: Ignoring Professor Michaelson’s argument in favor of tenure based on his personal bias.
3.3 Look Who's Talking (Tu Quoque)
Definition: Criticizing someone’s argument based on their failure to be consistent in their actions.
Example: A parent advising against skipping school while having skipped school themselves.
3.4 Two Wrongs Make a Right
Definition: Justifying a wrongful action by citing another wrong action.
Example: Justifying cheating because others are also cheating.
3.5 Scare Tactics
Definition: Threatening harm to convince someone to accept an argument.
Example: Politician claiming dire consequences if gun control measures are adopted.
3.6 Appeal to Pity
Definition: Evoking pity to gain support without relevant evidence.
Example: A student asking for a grade change due to personal troubles.
3.7 Bandwagon Argument
Definition: Arguing that a proposition must be true because many people believe it.
Example: Claiming astrology must be true because many Americans follow it.
3.8 Straw Man
Definition: Misrepresenting an opponent's argument to make it easier to attack.
Example: Distorting a politician’s speech against violent pornography as a call for complete censorship.
3.9 Red Herring
Definition: Introducing an irrelevant issue to divert attention from the original argument.
Example: Defending Thomas Jefferson’s presidency while ignoring criticism of his slavery ownership.
3.10 Equivocation
Definition: Using a word with multiple meanings within the same argument.
Example: Claiming that it's illegal for anyone to sell 'tanks' when the context shifts meaning.
3.11 Begging the Question
Definition: Assuming as a premise what one is trying to prove as a conclusion.
Example: Stating bungee jumping is dangerous because it is unsafe.
4. Summary of Fallacies of Relevance
Overview of fallacies discussed in Chapter 5, providing concise examples of each fallacy discussed.
Chapter 6: Fallacies of Insufficient Evidence
1. Introduction to Insufficient Evidence
Fallacies of insufficient evidence occur when premises are relevant but inadequate to support the conclusion.
2. Common Fallacies of Insufficient Evidence
2.1 Inappropriate Appeal to Authority
Definition: Citing a witness or authority who is not reliable.
Example: Believing claims made by a barber about Einstein’s theories.
2.2 Appeal to Ignorance
Definition: Claiming something is true because it hasn't been proven false.
Example: Believing in Bigfoot because no one can disprove its existence.
2.3 False Alternatives
Definition: Presenting only two options when more exist.
Example: Claiming we must choose a conservative candidate or face anarchy.
2.4 Loaded Question
Definition: Asking a question with an unfair assumption built in.
Example: Asking if someone is still cheating implies they have cheated before.
2.5 Questionable Cause
Definition: Claiming one event causes another without sufficient evidence.
Example: Assuming that drinking lemon tea cured a cold simply because it happened after.
2.6 Hasty Generalization
Definition: Drawing broad conclusions from limited evidence.
Example: Concluding all immigrants are criminals based on a few examples.
2.7 Slippery Slope
Definition: Asserting that one small step will lead to extreme negative consequences.
Example: Claiming legalizing marijuana will lead to complete societal breakdown.
2.8 Weak Analogy
Definition: Comparing two things that are not truly comparable.
Example: Comparing the dangers of teachers of false religions to plague carriers.
2.9 Inconsistency
Definition: Making claims that contradict each other.
Example: Asserting both that all moral judgments are relative while claiming a moral absolute.
3. Summary of Fallacies of Insufficient Evidence
Brief recap of the nine common fallacies, providing examples illustrating each.