18 Logical fallacies

The word “logic” comes from the Greek word “logos,” which has several translations, including word, reason and discussion. Logic is the study of correct reasoning or argumentation. This amounts to deriving valid inferences. Logical fallacies are erroneous arguments that can still appear believable because they can be psychologically convincing. Formal logic errors occur when there is an incorrect logical structure. Informal logic errors are arguments based on incorrect premises or confusing language. Here are some common logical fallacies:

18 Logical fallacies (reasoning errors)

  1. Ad hominem: a Latin phrase meaning "to the person." It refers to an argumentative strategy whereby an opponent's character or personal traits are attacked instead of addressing the substance of their argument. Example: “I really don't need to listen to your opinion because you are young and inexperienced.”
  2. Red herring: attempt to divert attention from the real issue by introducing irrelevant information or moving on to another topic. Example: “Let's not talk about climate change. What really matters is the economy. We have to focus on that.”
  3. Argument from ignorance: 1) arguing that a statement is true because it has not yet been proven to be false, or 2) arguing that a statement is false because it has not yet been proven to be true. Example: “The fact that we have never been able to prove the origin of UFOs shows that they were created by super-intelligent aliens.”
  4. Appeal to authority: reasoning that assumes something must be true because a person who is supposed to be an authority says it is true. Example: “Corona vaccines are dangerous because an acquaintance of mine, who studied biology, says they are dangerous.”
  5. Appeal to nature: stating that a product or practice is good because it is natural, or bad because it is non-natural. Example: "Vaccinations are unnatural, therefore they are bad for you.”
  6. Appeal to popularity: (also called: 'ad populum' and 'bandwagon fallacy') reasoning that assumes that something is true or good because many people agree with it. Example 1: “A majority of people eat meat so it must be good. Example 2: Other countries also emit large amounts of CO2, so it is wrong for our country to take strict measures to reduce CO2 emissions.”
  7. Appeal to tradition: Claiming that something is true because it has always been done or believed. Example: “We should keep the death penalty because it has been a tradition in our country for centuries.”
  8. Circular reasoning (also known as begging the question): reasoning in which what needs to be proven is already assumed in advance. Example: “God exists because it is stated in the Bible and what it says in the Bible is true because it is the word of God.”
  9. Equivocation: Changing the meaning of a term in the middle of an argument. Example: “I am against abortion because it is murder.” The equivocation lies in the word 'murder'. While “murder” legally refers to the unlawful killing of someone with premeditation, it can also be interpreted morally or emotionally in this context. Without specifying which meaning is being used, the argument can be ambiguous and misleading.
  10. Slippery slope: reasoning that assumes that a first step must lead to a chain of subsequent steps with extreme consequences. Example: “If we give John permission to work from home tomorrow, soon, we will never see him back at the office.”
  11. Non Sequitur: Drawing a conclusion that does not follow from the premise of the argument. Example: “I don't believe in climate change because it snowed today.”
  12. Hasty generalization: drawing conclusions based on too little information or unreliable data. Example: “All politicians are pickpockets because recently another one of them was caught for fraud.”
  13. Post-hoc ergo propter hoc: reasoning in which you assume that because event B comes after event A, B must have been caused by A. Example: “Measles vaccines cause autism because after my nephew was vaccinated he suddenly developed autism.”
  14. Just world fallacy: the belief that the world is inherently just and that people get what they deserve. Example: The assumption that people living in poverty are lazy or have made poor choices, without taking into account structural inequalities.
  15. Straw man reasoning: reasoning in which you misrepresent the other person's argument to make it easier to attack. Example: “Person A: “I think we should invest more money in education to improve the quality of education.” Person B: “So you're saying we should neglect other important sectors like healthcare and infrastructure? That is ridiculous!"
  16. False analogy: Comparing two unrelated things as if they were similar. Example: “Just as a family must adjust its spending to match its income, a country must adopt austerity measures when tax revenues decline.” (Explanation: While households must indeed adjust their spending, countries can use fiscal and monetary policy measures to boost incomes or justify expenditures that serve larger economic goals.)
  17. False dichotomy: incorrectly presenting a situation as a dichotomy, while in fact intermediate forms and mixed forms also exist. Example: “Alice says she wants to be a pop musician. Bob warns her: “In the music world there are two groups: a handful of superstars and a huge number of poor people. Are you sure you want to participate in such a lottery?”
  18. False dilemma: falsely pretending that there are only two options when multiple options exist. Example: “Emma indicates that the negative working atmosphere in the team bothers her. Hugh responds laconically: “Listen, Emma, ​​it's very simple. You have two options: either you stay and stop complaining, or you look for another job.”

How do we know if statements are true?

Why is it useful to know about these reasoning errors? Because they help you analyze whether statements are correct. A few years ago I designed a simple tool to help you determine whether to believe claims or not. The tool revolves around answering three questions (knowledge about reasoning errors is especially important for answering question 2):

  1. Is the statement clear?
  2. Does the statement make sense?
  3. Is the claim supported by evidence?