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What You Need to Know About Logical Fallacies

Mental Models Mar 14, 2022

The use of logic is a crucial part of any argument. Logic can help us to reach the correct conclusion, and it can also be used as a weapon against our opponents in arguments. We must understand logical fallacies so we know how to avoid them when formulating our arguments. In this post, we'll discuss what they are and why you need to be aware of them.

What is a fallacy?

A logical fallacy is a false argument used to try and convince someone of another opinion. These are flawed, deceptive, or false arguments that can be demonstrated to be false through reasoning. Sometimes, the person making the mistake will be unaware that they are doing it. Other times, they'll do it on purpose to make you believe something unlikely or untrue. In either case, knowing what these errors look like can help you both avoid them yourself and identify them in others.

Fallacies are divided into two categories:

A formal fallacy is a logical fallacy in which the premise and conclusion do not hold up under scrutiny.

An informal fallacy is a flaw in the argument's form, content, or context.

"Arguments and debates play an important role in academic and college discourse. However, not every argument is flawless. Some can be picked apart because of logical and rhetorical flaws."

Types of Logical Fallacies

Common types

The most common logical fallacy is an argument from ignorance, which means that someone believes something to be true because it has not been proven false. For example, if you were having a discussion about extraterrestrial life with someone who believed aliens do exist but have never seen one themselves, they might say "prove to me they don't exist!"

While it might sound reasonable to ask for proof of something, this is an error in logic. You cannot prove a negative- that means you can only provide evidence against the possibility of something being true, not actual evidence that it's false.

Another common logical fallacy is called the argument from authority. This one means that someone believes something to be true because it's been said by a respected or famous person. For example, if you asked your friend whether they thought global warming was real and they answered "Well Bill Nye the Science Guy says we're causing climate change, so I believe him."

This is an error in logic as well; just because someone is an expert in their field doesn't automatically mean they're right when it comes to other topics. This is especially true if the person with whom you are speaking believes that Bill Nye's opinion on climate change contradicts what another authority figure, like a teacher or scientist, has said.

A faulty generalization is another common logical fallacy. This indicates that a generalization has been made based on insufficient evidence. For example, if you were discussing gun control with someone and they said, "I think we should ban all guns because my friend's cousin was shot," you should be concerned.

This is fallacious reasoning; your friend's cousin getting shot doesn't give you enough information to base an argument on. You cannot generalize based on one or two specific experiences; to do so would be committing the fallacy of hasty generalization.

There are, unfortunately, many more logical fallacies than this! Knowing how to avoid them is important if you want your arguments and debates to be valid and effective. The next time you find yourself in a disagreement with someone, try to figure out if they're using logical fallacies. If so, ask them for evidence that supports their argument or challenge them on the specifics of what they've said.

Other types

The example above uses three types of fallacies, but there are many more logical fallacies you may have encountered at work. Six more common logical fallacies are listed below.

The Slippery Slope

The slippery slope argument works by convincing you that the worst that can happen will happen if you follow a certain path. This isn't always the case.

Example

"If Susan is allowed to leave early, we'll be able to give everyone Friday afternoon off soon.

This type of debate occurs frequently. However, a closer examination of the example reveals that concluding that allowing one employee to leave early one time will require you to give everyone an afternoon off every week is illogical.

The Fallacy of Jumping on the Bandwagon

You are persuaded to believe in an idea or proposition simply because it is popular or has a large following. However, just because a large number of people agree on something does not make it true or correct.

Example

"We polled all of our customers, and they unanimously agreed that staying open 24 hours a day would be a great idea. As soon as possible, we need to put together a 24-hour schedule.

Before you can draw any conclusions from an informal survey like this, you need to ask some more questions.

For instance, who were these individuals? Would they go to the store at 2 a.m. and buy something? If so, how often do you do it? What are the costs and benefits of such a strategy?

Keep in mind, however, that just because a lot of people believe in something doesn't mean it's true. Always try to think critically and avoid being swayed by persuasion.

Note:

The bandwagon fallacy is similar to the "appeal to tradition" fallacy. In this case, the debate revolves around something that has "always" been done or is a widely accepted practice. As an example, "We've always promoted from within the ranks to become the CEO. There will be too much disagreement and discord if we look outside."

The Fallacy of False Dichotomy

The false dichotomy fallacy is based on an "either-or" argument: you give people only two choices and force them to choose one. Neither option may be the best, and there may be a plethora of other options. However, the argument makes it appear as if the suggested option is the only viable option.

Example

"As a Board, we have the option of either approving this initial public offering or succumbing to our competitors' slow annihilation."

There are almost certainly other options that the Board could consider in this case. Is it even possible to improve or maintain a company's competitive position by raising capital?

The Fallacy of the Straw Man

Creating a false argument and then refuting it is known as the straw man fallacy. The counterargument is assumed to be correct at this point. Your preferred position appears stronger by misrepresenting an opposing position (and then knocking it down).

Example

In densely populated areas, a local politician plans to expand the municipality's cycle network and install several new speed cameras. As their opponent puts it, "They want us to all stop driving for good. They're punishing the law-abiding motorists and commuters who contribute to these politicians' salaries."

The opponent has easily demolished the position by claiming that the proposed changes are an attack on motorists, rather than addressing the actual concerns the proposal addresses โ€“ in this case, a rise in fatalities due to traffic collisions and pollution levels.

Note:

A straw man argument is not the same as a straw man proposal. You start with a half-finished idea and purposefully "poke holes" in it to get to a better final product with a straw man proposal.

When used with clear and honest intentions, a straw man proposal, unlike a straw man argument, is an effective process.

The Fallacy of the No True Scotsman

This is also known as an "appeal to purity," and it is a technique for dismissing flaws in an argument or criticisms of it.

The person who commits this fallacy "moves the goalposts" and shifts the terms of the argument so that the contradictory evidence does not apply, regardless of how compelling the counterargument is.

Example

A Scotsman, according to Andy, would never put sugar on his porridge. Dougal responds that he is a Scotsman who does sweeten his porridge. Andy counters that a true Scotsman would never put sugar in his porridge.

To support his position, Andy alters the terms of the debate by implying that Dougal is not a "true" Scotsman.

Selection by Observation

This means that you emphasize the positive aspects of a concept while ignoring the flaws. You're attempting to persuade your audience by only telling half of the story.

Example

"I'm aware that our television commercials are more effective than those on the radio. According to the numbers, we reached twice as many people with television ads, and our focus groups remembered the TV commercial 38 percent more than the radio spot."

This argument ignores the cost and returns on investment of television commercials versus radio commercials. Is there a link between the 38 percent increase in retention and sales conversions? How many people who listen to the radio versus those who watch TV buy the product?

If you become attached to an idea, especially if you were involved in its creation, it's easy to fall into observational selection.

A similar fallacy is the "statistics of small numbers" fallacy. You use one observation to draw a broad conclusion in this case.

As an example, "I would never use Gaudi Brothers as a paper supplier. They were used by my wife's company, and they short-shipped and back-ordered products."

This opinion is based on a single negative experience, and it does not imply that the company is always untrustworthy. It's possible that the purchasing company was late in submitting orders or paying invoices.

Why do people make these mistakes?

Logical fallacies are some of the most common mistakes that people make in everyday reasoning. They happen when someone is drawing a conclusion based on faulty logic, and they can be very dangerous. If youโ€™re not careful, logical fallacies can lead to all sorts of problems: poor decisions about what to do next; missed opportunities for success. With just a little knowledge and practice, you too can avoid these mistakes before they mess up your life.

Logical fallacies are everywhere and most people donโ€™t even realize it. Mostly, they come from a lack of knowledge or understanding of how logic works. This is one reason why logical fallacy examples exist in so many areas: politics, religion, educationโ€ฆ you name it. But, even if you try to avoid these specific areas of life where people use fallacies all the time (like politics and religion), itโ€™s easy for them to sneak in unnoticed and influence your decisions.

Logical fallacies are so common because the human mind is naturally drawn to quick and easy conclusions. This makes logical reasoning an incredibly difficult process for most of us, but itโ€™s also something that we need to get by every day. We just have to keep practicing until our minds learn how to do it on autopilot.

How can I avoid making these errors myself?

Logical fallacies are errors in reasoning that can be avoided.

Logical fallacies are often found in arguments between people who hold different positions on an issue. These errors of reasoning lead to faulty conclusions and should therefore be avoided, if possible.

You'll need a basic understanding of how an argument works to spot logical fallacies. In logic, an argument is a collection of statements from which one can infer the other (or others). There are two types of statements: declarative and non-discursive.

Premises are statements that are made to support an argument's conclusion.

Conclusions are statements that can be deduced from the evidence.

The premises must fully support the conclusion for an argument to be valid or logical. This can be accomplished in one of two ways:

1. Making Use of Inductive Reasoning

You begin with broad premises and work your way to a specific, predetermined conclusion.

Example

Premise 1: Trucan Supply decided to limit layoffs to the New York facility only to save money on redundancy.

Premise 2: Tom, a Trucan employee, was laid off.

Tom is employed at the New York facility.

2. Making Inductive Inferences

You begin with specific premises and work your way to a broad conclusion. This "bottom-up" logic relies on on-premises to arrive at a likely but not certain conclusion. (For more information, see our article on Inductive Reasoning.)

Example

Premise 1: In the last five years, April promotions have increased sales by 15% on average.

Premise 2: Summer promotions have not resulted in any measurable increase in sales during this period.

Conclusion: This year's promotion should be held in April rather than the summer to increase sales.

Use these two tests to see if an argument you're given has a solid foundation in logic. You can be confident that the argument is sound if it passes. If it doesn't, request additional information and evidence.

Conclusion

Logical fallacies are common in arguments. They can be difficult to identify because they donโ€™t always have a clearly identifiable pattern, but there are some signs that might help you recognize them when they happen. You may notice an argument has circular reasoning or is full of red herrings if these logical fallacies show up. Be on the lookout for any signifier that indicates someone may not be thinking critically about what he or she is saying.

Further Reading

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Seeking Wisdom

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