Informal Fallacies: 15 Common Examples of Faulty Reasoning

Fallacies are flawed patterns of reasoning that can lead to incorrect or misleading conclusions.

They can be categorised as formal and informal. Formal fallacies are errors in deductive reasoning where the form or structure of the argument is flawed, making it logically invalid. These fallacies occur when the conclusion does not necessarily follow from the premises, even if the premises are true. Examples of formal fallacies include denying the antecedent and affirming the consequent.

Informal fallacies, on the other hand, involve errors in reasoning that are not solely dependent on the structure of the argument. They often rely on the content, context, or language used to persuade or mislead the audience. Informal fallacies can be more subjective and context-dependent, which can make them harder to identify and analyse than formal fallacies.

In this post, we will look at 15 examples of informal fallacies:

Remember: Just because an argument involves a fallacy, this does not automatically mean the conclusion is false! If an argument involves a fallacy it means its conclusion does not necessarily follow from the premises – but the conclusion might be true anyway. 

1. Straw Man Fallacy: Misrepresenting the Argument

The Straw Man fallacy involves misrepresenting or distorting an opponent’s argument to make it easier to attack or refute. Instead of addressing the actual claims or positions put forth by the opposing side, a weakened or exaggerated version is presented and countered.

Example 1:

Person A: “I think we should invest more in improving public schools to enhance the quality of education.”

Person B (Straw Man Response): “So, you’re saying we should throw all our money into schools and have no funds left for anything else? That’s absurd!”

In this example, Person B misrepresents Person A’s argument by exaggerating it and creating a distorted version. Person A suggested investing more in public schools, but Person B responds by framing it as an extreme stance of allocating all funds to schools and neglecting other important areas. By constructing this exaggerated version, Person B avoids addressing the actual argument made by Person A.

Example 2:

Person A: “I believe it’s important to limit screen time for children and encourage more outdoor activities to promote their physical and mental well-being.”

Straw Man Response: “So, you want to completely forbid children from using any electronic devices and isolate them from the digital world?”

2. Begging the Question Fallacy: Circular Reasoning

The Begging the Question fallacy occurs when the conclusion of an argument is assumed to be true within the premises. It’s sometimes referred to as the circular reasoning fallacy. The argument fails to provide sufficient evidence or support for its claim, assuming what it is trying to prove.

Begging the question fallacy can be deceptive as it creates an illusion of support for the conclusion without offering any external evidence or logical reasoning.

There are a couple of arguments that can be accused of Begging the Question in A level philosophy. For example, in metaethics, the argument that anti-realism must be false because of moral progress assumes moral properties exist in order to prove that moral properties exist. Elsewhere, in metaphysics of mind, the argument that eliminative materialism must be false because it is self-refuting essentially assumes folk psychology is true in order to prove folk psychology is true.

Example 1:

“The Bible is the word of God because it says so, and we know it’s true because it is the word of God.”

The argument assumes the conclusion, which is that the Bible is the word of God, by using the Bible’s claim as evidence. It creates a circular reasoning where the claim’s truth is established solely by the claim itself.

In this case, the argument presupposes that the Bible is the word of God without providing any external evidence or logical reasoning to support this claim. The claim is circularly justified by referring back to itself as evidence. This reasoning fails to offer a solid foundation for the assertion and doesn’t provide an objective or independent basis for accepting the Bible as the word of God.

Example 2:

“This policy is beneficial because it is the best option available, and it is the best option available because it is beneficial.”

3. Equivocation Fallacy: Shifting the Meaning of a Key Term

The Equivocation fallacy occurs when a key term or phrase is used with different meanings throughout an argument, leading to confusion or ambiguity. It exploits the multiple meanings of a word to make the argument appear stronger or more valid than it actually is.

An example of the Equivocation fallacy in A level philosophy can be found in evaluation of Malcolm’s ontological argument. Some critics argue that this argument is invalid as the meaning of “necessary” changes between the premises of the argument and the conclusion.

Example 1:

“Only man is rational. No woman is a man. Therefore, no woman is rational.”

In this example, the term “man” is used in two different senses:

  • First, as a generic term for humanity
  • Second, as a term referring specifically to males.

This specific variation of the equivocation fallacy is known as the four terms fallacy.

It’s called the four terms fallacy because there are supposed to be just three terms in such an argument (here: man, woman, and rational). However, in this example there are actually four terms on account of the two different meanings of ‘man’.

Example 2:

Equivocation is most obvious when used in variations of the four terms fallacy like the one above. But it can occur whenever someone uses an ambiguous term.

A classic example to illustrate this is a drunk driver who has consumed 2 beers and an entire bottle of vodka. When pulled over by the police, he says: “I only had a couple of beers”.

In this example, what the driver means by “couple of beers” means something different to what he hopes the police will interpret it to mean. The statement is literally true (the driver did only have 2 beers), but could be interpreted in a way that hides the truth (that the driver had 2 beers and no other alcoholic drinks, which is false).

4. Fallacy of Composition: Inferring Whole from Parts

The Fallacy of Composition assumes that what is true for individual parts of something must also be true for the whole. It erroneously attributes characteristics of the parts to the entire entity without considering emergent properties or interactions.

An example of the fallacy of composition in A level philosophy can be found in discussions of cosmological arguments. Russell argues these arguments are invalid because they conclude that the universe itself has a cause from the observation that everything within the universe has a cause.

Example 1:

“Each piece of paper in this book is thin. Therefore, this entire book must be thin.”

In this example, the fallacy is committed by assuming that because each piece of paper in the book is thin, the entire book must also be thin. This reasoning overlooks the fact that the book is composed of many individual pages stacked together. While each page may be thin, the accumulation of multiple pages results in a thicker book. Therefore, it is incorrect to assume that the entire book shares the same characteristic (thinness) as its individual parts (thin pages).

Example 2:

“Each player on the team is highly skilled. Therefore, the entire team must be unbeatable.”

5. Fallacy of Division: Inferring Parts from the Whole

The Fallacy of Division is the opposite of the fallacy of composition above. It assumes that what is true for the whole must also be true for its individual parts. It incorrectly attributes characteristics of the whole to its constituent parts without considering variations or differences.

Example 1:

“The company is very successful. Therefore, each employee must be highly successful.”

In this example, the fallacy is committed by assuming that because the company as a whole is successful, each employee must also be highly successful. However, this assumption may not be accurate. While the company as a collective entity may be thriving, individual employees may have varying levels of success or performance. It is incorrect to assume that the success of the company automatically translates to the success of each individual employee.

Example 2:

“Our country has a high GDP. Therefore, every citizen must be wealthy.”

6. Ad Hominem Fallacy: Attacking the Person, Not the Argument

The Ad Hominem fallacy involves attacking the character or personal traits of an individual making an argument instead of addressing the substance of their argument. This fallacy aims to discredit the person rather than engaging with the actual ideas being presented.

Example 1:

Person A: “We should invest more in healthcare to ensure everyone has access to quality medical services.”

Person B (Ad Hominem Response): “Opponent A is just a greedy doctor who wants to increase their own profits.”

In this case, the response targets Person A’s character by accusing them of being a greedy doctor motivated by personal financial gain rather than engaging with the argument itself.

By focusing on the character of the opponent rather than the merits of their argument, the Ad Hominem fallacy deflects attention from the actual topic and tries to discredit the person making the argument rather than addressing the substance of their claims.

Example 2:

Worker A: “I believe implementing flexible working hours would benefit employees and lead to higher productivity.”

Ad Hominem Response: “Well, you’re always late to work and never meet deadlines, so your opinion on productivity doesn’t matter.”

7. Genetic Fallacy: Judging Based on Origin or Source

This one is closely related to the Ad Hominem fallacy above. The Genetic Fallacy involves dismissing or accepting an idea based on its origin or source, rather than evaluating the idea itself on its own merits. This fallacy fails to address the actual content or validity of the argument.

Example 1:

“You can’t trust anything he says. He comes from a family with a history of criminal behaviour.”

In this example, the person dismisses the credibility of someone’s statements by pointing out their family background with a history of criminal behaviour. This fallacy assumes that the person’s family history automatically makes their statements unreliable or untrue.

Example 2:

“That research paper can’t be reliable. It was published in a lesser-known journal.”

8. Appeal to Authority Fallacy: Relying Solely on Expert Opinion

The Appeal to Authority fallacy occurs when an argument relies on the opinion or testimony of an authority figure or expert in a particular field, without sufficient evidence or reasoning to support the claim.

Example 1:

“Dr. Smith, a renowned physicist, says that ghosts exist. Therefore, ghosts must be real.”

In this example, the argument is based on the statement made by Dr. Smith, a renowned physicist, who claims that ghosts exist. The fallacy occurs when the conclusion that ghosts must be real is drawn solely based on Dr. Smith’s authority and reputation as a physicist, rather than providing substantial evidence or logical reasoning to support the existence of ghosts. The fallacy assumes that the authority’s opinion is always correct, without critically examining the evidence or arguments for the claim.

Example 2:

“The experts say medicine X is effective and necessary, so you should trust its effectiveness and necessity without question.”

9. Slippery Slope Fallacy: Predicting Extreme Consequences

The Slippery Slope fallacy asserts that a small action or decision will lead to a chain of increasingly dire or extreme events, without providing sufficient evidence to support the claim. It assumes a linear cause-and-effect relationship without considering other factors or possible outcomes.

Example 1:

“If you try one cigarette, you’ll become addicted to smoking. Soon, you’ll be smoking a pack a day, get cancer, and die.”

This example illustrates the slippery slope fallacy by suggesting that trying one cigarette will inevitably lead to a chain of negative outcomes, including addiction, health problems, and death. While it’s true that smoking can be addictive and harmful, this argument overlooks the fact that individuals have different responses to smoking, and not everyone who tries a cigarette becomes a regular smoker. It fails to acknowledge personal agency, potential interventions, and the ability to make informed choices regarding one’s health.

Example 2:

“If we allow students to use smartphones in the classroom for educational purposes, it will lead to complete chaos. Next, they’ll be using them for social media, then they’ll start cheating on tests, and eventually, no one will be focused on learning anymore.”

10. False Dilemma Fallacy: Presenting Limited Options

The False Dilemma fallacy, also known as the Black-and-White fallacy, presents a situation as if there are only two possible options or outcomes when, in reality, there are more. It oversimplifies complex issues and fails to acknowledge alternative perspectives or solutions.

Example 1:

“You’re either a success or a failure. If you haven’t achieved great things in your career, then you’re a failure.”

This example employs a false dilemma by creating an either-or scenario, where success is defined narrowly as achieving great things in one’s career, and anything short of that is deemed failure. It disregards the various measures of success, personal fulfilment, and happiness that can exist outside traditional notions of professional achievements. It oversimplifies the complexity of human experiences and reduces success to a single parameter.

Example 2:

“You’re either with us or against us. If you don’t support our political party, you must be against the country.”

11. Hasty Generalisation Fallacy: Drawing Conclusions from Insufficient Evidence

The Hasty Generalisation fallacy occurs when a general conclusion is drawn based on a limited sample size or insufficient evidence. It fails to consider the individual differences or variations within a group and makes sweeping generalizations. Hasty generalizations overlook the need for a larger sample size and more comprehensive evidence to make accurate and justified generalizations about a particular group or population.

Example 1:

“I met one rude person from that country, so all people from that country must be rude.”

In this case, encountering one rude person from a particular country leads to the hasty conclusion that all people from that country are rude. This conclusion fails to consider the individual differences within a country and disregards the fact that individuals can vary greatly in their behaviour, attitudes, and characteristics. It unfairly stereotypes and assumes that the behaviour of one person represents an entire group.

Example 2:

“I tried one brand of this product, and it didn’t work for me. Therefore, all brands of this product must be ineffective.”

12. Appeal to Ignorance Fallacy: Arguing Based on Lack of Evidence

The Appeal to Ignorance fallacy asserts that something must be true because it has not been proven false or vice versa. It exploits gaps in knowledge or lack of evidence to make a claim without proper justification.

Example 1:

“There’s no evidence that medicine X is harmful, so medicine X is safe.”

In this case, the argument states that since there is no evidence indicating that medicine X is harmful, it is automatically considered safe. However, this reasoning is flawed because the absence of evidence does not guarantee the truth of a claim. For example, there could simply have been no safety tests conducted on medicine X – in which case there would be no evidence it is harmful – but this would not be the same as conducting the tests and proving medicine X actually is safe.

Example 2:

“No one has disproven the existence of aliens, so aliens must exist.”

13. Red Herring Fallacy: Distracting from the Main Issue

The Red Herring fallacy involves diverting attention from the main topic or argument by introducing unrelated or irrelevant information or ideas. It aims to confuse or mislead the audience and steer the discussion away from the central point.

Example 1:

Person A: “You should really start cleaning up your dirty dishes after meals. It’s not fair for others to have to deal with the mess.”

Person B (Red Herring Response): “Well maybe I wouldn’t leave dishes in the sink if you didn’t blast your music late at night. It’s disruptive and inconsiderate.”

In this scenario, Person A raises a concern about dirty dishes left in the sink. However, instead of addressing the issue at hand, Person B redirects the conversation by bringing up an unrelated complaint about Person A’s loud music. By shifting the focus to another topic, Person B attempts to divert attention from their own behaviour and avoid taking responsibility for their actions. This tactic of introducing a different issue to sidestep the original argument makes it an example of the Red Herring fallacy.

Example 2:

“When asked about their involvement in the scandal, the politician starts talking about their accomplishments in office.”

14. False Cause Fallacy: Assuming Causal Relationship without Evidence

The False Cause fallacy assumes a cause-and-effect relationship between two events simply based on their correlation, without providing sufficient evidence to establish a direct causal connection.

Example 1:

“Every time I wear my lucky socks, my team wins. Therefore, my lucky socks must be the reason for their victories.”

In this example, the individual believes wearing their lucky socks directly leads to their team’s victories. However, correlation does not automatically prove causation: Just because the person wears their lucky socks and their team wins, it does not necessarily mean that the socks are the cause of the victories. It neglects the possibility of other variables, such as team performance, strategies, or even luck.

Example 2:

“Crime rates increased after the release of that violent video game, so the game must be causing the rise in crime.”

15. Appeal to Nature Fallacy: Assuming Natural is Always Better

The Appeal to Nature fallacy asserts that because something is natural, it is inherently better or more desirable (and if something is unnatural it is inherently worse or less desirable). It assumes that natural things are always good or safe, while artificial or synthetic things are always bad or harmful.

Note: Don’t confuse the appeal to nature fallacy with Moore’s naturalistic fallacy from metaethics.

Example 1:

“Processed foods contain artificial ingredients, but these organic fruits are natural, so they must be healthier and better for you.”

This example assumes that natural or organic products are always superior or healthier simply because they are natural. And while organic fruits are probably healthier than most processed foods, it disregards other important factors such as nutritional content, preparation methods, and individual dietary needs.

In the context of food, natural = healthy works quite well as a rule of thumb (many processed foods are absolute poison!). But, because this is a fallacy, the conclusion does not necessarily follow. To use an extreme example to illustrate this: Death cap mushrooms are natural, but vinegar is highly processed. However, death cap mushrooms make you incredibly ill whereas vinegar can improve your health by increasing insulin sensitivity. So, in this case, natural does not automatically mean better or healthier!

Example 2:

“Chemical medications have side effects, but this herbal remedy is all-natural, so it must be completely safe and effective.”

The philosophy textbook written with the student in mind!