Have you ever lost an argument even though you knew you were right? There is a high chance that your opponent was — either deliberately or unknowingly — using logical fallacies to defeat you.
More often than not, these flaws in reasoning play a role in arguments. They may be committed unintentionally due to a lack of argumentation skills, however, they are frequently used as a persuasion strategy for one’s personal advantage. For instance, in domains such as politics and advertising, logical fallacies are used skillfully to influence the audience’s opinion and behavior.
Understanding how fallacies work and knowing how to spot them in a discussion can be a useful skill for almost anyone: It can lead to personal empowerment by helping you to form better, more persuasive arguments, as well as defend yourself from people who wish to influence your thinking in a way that may be against your best interests.
To help you begin your learning journey, or to refresh your memory, here’s a list of 10 fallacies that are among the most common ones.
1. Ad Hominem
Ad hominem, which is Latin for “against the man”, is undoubtedly one of the most common logical fallacies and often the bread and butter of political debates and campaigns.
This offender occurs when someone attacks directly the person making an argument rather than criticizing the argument itself. In other words, one replaces logical argumentation with attacks directed towards their opponent’s personal qualities, such as their character, background, intelligence, morals, physical appearance, reputation, or credentials.
As such, ad hominem is considered a logical fallacy because, in reality, insults and other verbal attacks do nothing to disprove the substance of the actual being made.
- “You didn’t even finish high school. How could you possibly know about this?”
- Caitlyn: “All murderers are criminals, but thieves aren’t murderers, so they can’t be criminals.”
- Jim: “Well, you’re a thief and a criminal, so there goes your argument.”
2. Straw Man
The straw man occurs when someone attacks a distorted version of the original argument that they have themselves created (i.e “the straw man”). In fact, they attack an argument the opponent doesn’t really hold in order to ridicule or disproof their claims.
The argument goes like this:
- Person A makes a claim.
- Person B creates a distorted version of the claim.
- Person B attacks the distorted version.
The distorted version is unrelated or only remotely related to the original claim, and may be oversimplified, exaggerated, taken out of context, or focus only on a specific aspect of the argument. The straw man argument, like ad hominem, is a common occurrence in politics and debates on any controversial topic.
- “Tree-huggers” are dumb because they think plants have feelings and are more important than humans.”
- Jim: “I think our company should allocate a larger portion of the budget to customer support. It is clearly lacking behind other areas.”
- Andy: “We’ll go bankrupt if we spend all our money on customer support.”
3. Appeal to Authority
Appeal to authority works by claiming that something must be true because it is backed up by someone who is (at least allegedly) an authority on the subject.
Although an appeal to authority is by no means always unfounded, it can be misused. If all someone does to support their arguments is to appeal to a figure of authority, and without providing sufficient evidence that the authorities are correct, it quickly becomes fallacious.
Appeal to false authority is a more specific variation of this fallacy. As the name suggests, it refers to the use of incompetent or irrelevant authorities.
Practically any celebrity endorsement in advertising could be considered as an appeal to false authority: For example, a commercial claiming that a specific brand of cereal is the best way to start the day because Tiger Woods has it for breakfast would be logically fallacious since Tiger’s expertise lies in a completely different field.
- “An environmental scientist, who has been studying climate change for several years, says that global warming is not real. Therefore, it cannot be real.”
- “Three out of four yoga teachers say that stretching makes your life meaningful.”
4. Slippery Slope
The slippery slope fallacy, also known as “absurd extrapolation”, works by moving an argument from a sensible premise to an undesirable or extreme conclusion via a number of steps. The first, seemingly unimportant event is suggested to lead to a more significant event, which leads to an even more significant event, and so on.
As such, its logical form is:
- If A, then B.
- If B, then C.
- If C… then ultimately X.
The conclusion of the argument, or the culmination of the chain of events, is seen as unacceptable and therefore it is argued that the first decision or action must be rejected.
- “If we legalize gay marriage, next people will want to legalize polygamy.”
- “Legalizing prostitution would cause more marriages to break up, which would cause the breakdown of families, which would finally result in the destruction of civilization.”
5. The Bandwagon
The bandwagon fallacy, which is especially common in the world of advertising, is based on the assumption that the opinion of the majority is always correct. In other words, if most people do or believe something, it cannot be wrong or incorrect.
It is sometimes called “appeal to popularity” or “argumentum ad populum” (which is Latin for the appeal to the people).
It’s a fallacy because it offers the appeal instead of making a valid argument; it only shows that something is popular without taking into account that people may well be mistaken or deceived. For instance, people used to believe that the sun was orbiting the earth and not the other way around, but this obviously wasn’t true.
Furthermore, the name “bandwagon” comes from the times when politicians used to ride through the streets as part of their political campaigns, and people who supported that politician would jump on their bandwagon.
- “Mc’donalds has served 100 billion people in the world. It must be the best fast food restaurant.”
- “Everyone is buying the new iPhone that’s coming out this weekend. You have to buy it too!”
6. Appeal to Ignorance
This logical fallacy is based on the assumption that if we cannot prove something, it must be true or false. That is, an argument must be true if it cannot be proven false, and if it cannot be proven false, it must be true.
In reality, appeal to ignorance only succeeds in illustrating one thing: that we don’t know something. If such an argument was valid, it could often be applied to support two opposing claims, which is a clue that it is based on flawed reasoning. For example: “you cannot prove that ghosts don’t exist; therefore they exist” and “you cannot prove that ghosts exist; therefore they don’t exist”.
- “You cannot prove that God does not exist; therefore God exists.”
- “No one has ever proven that UFOs haven’t visited earth yet, so they must have visited earth.”
7. False Dilemma
False dilemma is another common line of flawed reasoning. It occurs when only two choices – that are often extreme opposites – are presented as the only possibilities when, in fact, there are other alternatives.
For example, if someone asserts that “you either love me, or you hate me”, they would be committing the false dilemma since there are other possibilities for how people can feel for each other.
It’s also known as the “either-or fallacy”, “all-or-nothing fallacy” and “black-and-white fallacy”.
- “I didn’t see you at the charity fundraiser today. I guess you are not a good person after all.”
- “We either keep euthanasia illegal and show that we value human life, or we legalize euthanasia and decide that human life is worthless”
8. Hasty Generalization
Also known as “faulty generalization” and “argument from small numbers”, this common offender occurs when a general conclusion is drawn based on a sample size that is too small.
In other words, the conclusion is made hastily without looking at a broader range of relevant data, and thus lacking sufficient evidence to support it.
This fallacy can be tough to overcome because there are often our built-in biases involved behind incorrect generalizations and stereotyping.
- “I just arrived in this country and the first 2 local people I met were so rude. Everyone in this country must be unfriendly!”
- “My dad has smoked 2 packs of cigarettes per day for 30 years. Smoking can’t be dangerous!”
9. The Red Herring Fallacy
The red herring is a fallacy that works by derailing the actual issue being discussed to an irrelevant topic. It is a deliberately made diversion, and it is a common strategy used when the topic is disadvantageous or uncomfortable to the arguer.
The diversion often seems like it is a valid point or a counter-argument, when in fact it has only a surface relevance to the real issue at hand.
The name of this fallacy apparently refers to a type of herring, a smelly fish that was used to train hunting dogs since its strong smell was well-suited for training them to track scents without getting distracted.
- Daughter: “I’m so hurt that my boyfriend broke up with me.” Mother: “Think of all the poor starving children in Africa. Your problems will seem pretty insignificant then.”
- “I don’t think that evolution is a good explanation for the origin of human life. Also, It makes me offended that you would suggest that I came from a monkey.”
10. Appeal to Tradition
Appeal to tradition occurs when it’s claimed that something must be good or true because it has been practiced for a long time (that is, traditionally).
Arguments made on this basis are fallacious since the main evidence for them are historical preferences, not relevant facts and logical reasoning; the mere fact that a belief or behavior is traditional does not prove that it must be right or better than its newer alternative.
As John Locke, a well-known English philosopher, pointed out:
New opinions are always suspected, and usually opposed, without any other reason but because they are not already common.
- “Religion X has been around for thousands of years; therefore, it must be a good religion.”
- “People have believed the earth is flat for much longer than it is round. For this reason, I choose to believe that the earth is flat.”