Traps Are Everywhere

Common Logical Fallacies

1. Formal Fallacies

1.1 Affirming the Consequent

• Explanation: Believing that if the conclusion is true, the premise must also be true. In reality, the establishment of the conclusion cannot reversely deduce the establishment of the premise.

• Example: If it rains, the ground is wet. The ground is wet, therefore it rained. (Ignoring other possible causes of wet ground)

1.2 Denying the Antecedent

• Explanation: Erroneously believing that if the premise doesn't hold, the conclusion also doesn't hold. In reality, the negation of the premise doesn't necessarily lead to the negation of the conclusion.

• Example: If it rains, the ground is wet. It didn't rain, therefore the ground isn't wet. (Ignoring other possible causes of wet ground)

2. Informal Fallacies

2.1 Fallacies of Language

2.1.1 Equivocation

• Explanation: Using multiple meanings of a word in the argumentation process to mislead the audience.

• Example: Humans are rational animals. Pigs are not human, therefore pigs are not rational animals. (Switching the meaning of "human")

2.2 Fallacies of Relevance

2.2.1 Ad Hominem

• Explanation: Refuting the opponent's argument by attacking their personal characteristics, rather than discussing the argument itself.

• Example: You don't understand economics at all, so your opinion is invalid.

2.2.2 Appeal to Authority

• Explanation: Believing that an authority figure's opinion must be correct, without examining the argument itself.

• Example: A famous professor said this theory is correct, so we should believe it.

2.2.3 Appeal to Emotion

• Explanation: Influencing judgment by arousing emotions (such as fear, pity, etc.) rather than based on rational reasoning.

• Example: If you don't support this policy, many innocent children will suffer because of it.

2.2.4 Straw Man

• Explanation: Distorting the opponent's view, attacking this false view rather than the opponent's actual argument.

• Example: You say we should reduce military spending, so you don't care about national security.

2.3 Causal Fallacies

2.3.1 Post Hoc Ergo Propter Hoc

• Explanation: Believing that because event B occurred after event A, A must have caused B.

• Example: I wore my lucky shirt and then passed the exam, so the shirt brought me good luck.

2.4 Fallacies of Assumption

2.4.1 Slippery Slope

• Explanation: Assuming that a small event will inevitably lead to a chain of negative consequences, without reasonable evidence.

• Example: If we allow students to bring phones to class, the next step is they'll demand to play games, and eventually the entire education system will collapse.

2.4.2 False Dilemma

• Explanation: Simplifying complex issues into two extreme options, ignoring other possibilities.

• Example: Either you're with us, or you're our enemy.

2.5 Fallacies of Insufficient Evidence

2.5.1 Hasty Generalization

• Explanation: Drawing general conclusions based on a small, unrepresentative sample.

• Example: The two French people I met were unfriendly, therefore all French people are unfriendly.

Extended Learning Resources

1. Web Resources

1.1 Wikipedia - Logic

• Link: Logic - Wikipedia

• Introduction: The "Logic" entry on Wikipedia provides an overview of logic, including formal logic, informal logic, logical fallacies, etc. Suitable for beginners to quickly understand the basic framework of logic.

1.2 YourLogicalFallacyIs

• Link: YourLogicalFallacyIs

• Introduction: This is a website dedicated to introducing logical fallacies, providing easy-to-understand diagrams and explanations to help you identify and avoid common logical errors. The website also has a Chinese version.

1.3 Critical Thinking Web

• Link: Critical Thinking Web

• Introduction: A critical thinking resource website provided by the University of Hong Kong, covering logical reasoning, deductive and inductive reasoning, logical fallacies, etc. Suitable for in-depth study of logic and its applications.

2. Book Recommendations

2.1 "Introduction to Logic"

• Authors: Irving M. Copi, Carl Cohen

• Introduction: A classic logic textbook covering formal logic, informal logic, reasoning rules, and logical fallacies, suitable for readers with some foundation.

2.2 "What is Logic"

• Author: He Huaihong

• Introduction: An easy-to-understand introductory book on logic, suitable for beginners interested in logical thinking.

2.3 "Critical Thinking"

• Author: Diane Halpern

• Introduction: This book not only discusses logical reasoning but also covers how to apply critical thinking in daily life, helping readers identify fallacies and improve thinking skills.

3. Online Courses

3.1 Coursera - Introduction to Logic

• Provider: Stanford University

• Link: Introduction to Logic

• Introduction: This course covers the basics of formal logic, including propositional logic and predicate logic, suitable for beginners interested in logical reasoning.

3.2 edX - Critical Thinking Skills for University Success

• Provider: University of Sydney

• Link: Critical Thinking Skills for University Success

• Introduction: This course focuses on the application of critical thinking in academics, covering logical reasoning and fallacy identification, suitable for learners looking to improve their critical thinking skills.

3.3 Khan Academy - Logic

• Provider: Khan Academy

• Link: Khan Academy Logic

• Introduction: Khan Academy offers free courses related to logical reasoning, suitable for beginners to quickly get started.