Guide to Informal Logical Fallacies

Guide to Logical Fallacies

Group 1: Argue Against an Idea

1. Ad Hominem

Attacking the person making the argument rather than addressing the argument itself.

Formula: Person A makes argument X. Instead of addressing X, attack Person A's character or circumstances.

Example: "You can't trust his views on urban planning; he's never lived in a big city."

Counter: Refocus the discussion on the merits of the argument, regardless of who is making it.

Counter Example: "Let's examine the urban planning proposal itself, rather than focusing on personal experiences."

2. Strawman

Misrepresenting or oversimplifying an opponent's argument to make it easier to attack.

Formula: Person A states position X. Person B exaggerates, distorts, or oversimplifies X into Y, then argues against Y.

Example: "People who support renewable energy want to shut down all traditional power plants immediately."

Counter: Clarify the actual position and highlight the discrepancies between the original argument and the distorted version.

Counter Example: "Most renewable energy advocates actually argue for a gradual transition, not an immediate shutdown. Let's discuss the real issues of energy sustainability and economic impact."

3. Sunk Cost Fallacy

Continuing a behavior or endeavor due to previously invested resources.

Formula: Because we've already invested X in Y, we must continue with Y regardless of future costs or benefits.

Example: "We've already spent three years on this software project, so we have to finish it no matter what."

Counter: Evaluate future costs and benefits independently of past investments.

Counter Example: "Let's assess whether completing the project will be beneficial for the company, regardless of the time we've already invested."

4. Red Herring

Introducing an irrelevant topic to divert attention from the original issue.

Formula: During a discussion about A, introduce unrelated topic B to shift focus away from A.

Example: In a debate about education reform, suddenly bringing up the candidate's vacation habits.

Counter: Acknowledge the new topic but redirect the conversation back to the original subject.

Counter Example: "While personal time management is interesting, it doesn't address our current discussion on education reform. Let's return to the main issue."

5. Begging the Question

Making an argument where the conclusion is assumed in one of the premises.

Formula: Premise assumes the truth of the conclusion, often restating the conclusion in different words.

Example: "This book is a bestseller because it's popular."

Counter: Use the Socratic method to question the underlying assumptions and break the circular reasoning.

Counter Example: "What makes a book popular? Are there other factors besides sales that contribute to its popularity?"

Group 2: Argue against an Evidence

1. Compartmentalization

Isolating conflicting ideas or evidence to avoid cognitive dissonance.

Formula: Accept idea A in context X, but reject the same idea in context Y without acknowledging the contradiction.

Example: A business person who advocates for free market principles in their work but supports protectionist policies for their own industry.

Counter: Address the overarching principle or idea that spans multiple contexts.

Counter Example: "Let's consider how the principles of economic competition apply to both global markets and specific industries."

2. Self-Sealing

Constructing an argument that cannot be falsified or disproven.

Formula: Make a claim that, by its nature, rejects or explains away any potential counterevidence.

Example: "If you don't see the benefits of this self-help program, it's because you're not trying hard enough."

Counter: Introduce the concept of falsifiability and challenge the argument's testability.

Counter Example: "What evidence would you accept as proof that the program might not work for everyone? If there's no such evidence, how can we objectively evaluate its effectiveness?"

Group 3: Argue just after an event

1. False Analogy

Drawing a comparison between two things that are not truly comparable.

Formula: A is like B. B has property X. Therefore, A must also have property X.

Example: "Managing a household budget is just like managing a national economy."

Counter: Highlight the significant differences between the compared items.

Counter Example: "While both involve financial decisions, national economies have complex factors that households don't face, such as monetary policy and international trade."

2. Shoehorning

Forcing a fact or idea to fit a predetermined narrative or explanation.

Formula: Event A occurs. Force A to fit into explanation B, even if there's no clear connection.

Example: Blaming a sports team's loss on a fan's choice of shirt color.

Counter: Demonstrate the lack of a causal link between the event and the proposed explanation.

Counter Example: "There's no evidence linking shirt color to team performance. Let's look at factors like player strategy and opponent strengths instead."

3. Hasty Generalization

Drawing a broad conclusion from insufficient evidence.

Formula: Observe A in a small sample. Conclude A is true for the entire population.

Example: "I had two bad meals at local restaurants, so all the food in this city must be terrible."

Counter: Emphasize that a single instance or small sample is inherently biased and unrepresentative.

Counter Example: "Two meals can't represent an entire city's culinary scene. We'd need to try a much larger, diverse sample of restaurants to draw any meaningful conclusions."

4. False Cause

Assuming that because two events occur together, one must cause the other.

Formula: A occurs with B, after B, or ignoring common cause C. Therefore, A causes B.

Example: "I started using this new app and my productivity increased, so the app must be responsible for my improved productivity."

Counter: Point out that correlation does not imply causation.

Counter Example: "Many factors can influence productivity. Without controlled experiments, we can't attribute the improvement solely to the app."

5. Slippery Slope

Assuming a small action will inevitably lead to a chain of related events.

Formula: If A happens, then B will happen, which will lead to C, D, and eventually Z.

Example: "If we allow students to choose their own reading materials, they'll stop reading classics altogether."

Counter: Demonstrate alternative outcomes or stopping points along the proposed chain of events.

Counter Example: "Allowing students to choose some of their reading materials doesn't mean they'll never read classics. Many schools successfully balance student choice with curriculum requirements."

Group 4: Appealing an Idea

1. False Dichotomy

Presenting only two options when other alternatives exist.

Formula: Present A and B as the only options, ignoring possibilities C, D, E, etc.

Example: "Either we cut all funding to this program or we'll go bankrupt."

Counter: Identify and present additional options or middle ground.

Counter Example: "There are many approaches we could take. For instance, we could reduce funding partially, seek additional revenue sources, or restructure the program for efficiency."

2. Appeal to Ignorance

Arguing that a claim is true because it hasn't been proven false, or vice versa.

Formula: X hasn't been proven false, therefore X is true. Or, X hasn't been proven true, therefore X is false.

Example: "No one has proven that this ancient remedy doesn't work, so it must be effective."

Counter: Explain that absence of evidence is not evidence of absence.

Counter Example: "Just because we haven't found evidence against something doesn't make it true. We need positive evidence from clinical trials to support the remedy's effectiveness."

3. Appeal to Authority

Claiming something is true because an authority figure says it is.

Formula: Authority figure A says X is true. Therefore, X must be true.

Example: "This famous entrepreneur says this investment strategy works, so it must be foolproof."

Counter: Evaluate the authority's relevant expertise and look for supporting evidence.

Counter Example: "While the entrepreneur is successful, let's look at financial analyses and market trends to verify the strategy's effectiveness for different situations."

4. Appeal to People

Arguing that something is true because it's popular or appeals to vanity or snobbery.

Formula: Many people believe X, or X makes you superior, so X must be true.

Example: "All the influential people in town belong to this club, so it must be the best."

Counter: Show that popularity or status appeal doesn't determine truth or quality.

Counter Example: "Popularity among certain groups doesn't always indicate quality. Let's look at the club's actual offerings and compare them objectively with other options."

5. Appeal to Emotions

Using emotional manipulation instead of logic to win an argument.

Formula: Evoke emotion E (pity, fear, shame, etc.) to support conclusion C.

Example: "If you really cared about the environment, you'd buy this eco-friendly product."

Counter: Acknowledge emotions but refocus on factual evidence and logical reasoning.

Counter Example: "While environmental concerns are important, let's examine the actual impact of this product based on lifecycle assessments and compare it with alternatives."

Group 5: Probability or Data Fallacy

1. Cherry-picking and Confirmation Bias

Selecting data that supports one's position while ignoring contradictory evidence.

Formula: Present evidence A, B, C that support X, while ignoring evidence D, E, F that contradict X.

Example: Citing only customer reviews that praise a product, ignoring those that mention flaws.

Counter: Present a comprehensive view including contradictory evidence.

Counter Example: "While those reviews are positive, let's also consider these other reviews that mention issues. A balanced view helps us understand the product's strengths and weaknesses."

2. Gambler's Fallacy

Believing that past random events affect future outcomes in independent events.

Formula: Event A has occurred X times in a row, so event B is more likely to occur next time.

Example: "The coin has landed heads 5 times in a row, so it's due for tails."

Counter: Explain that each event is independent and past outcomes don't influence future probabilities.

Counter Example: "Each coin toss is an independent event. The probability of getting tails remains 50% regardless of previous tosses."

3. Ludic Fallacy

Assuming that the rules of a model or game apply to real-life situations.

Formula: In game/model A, rule B applies. Therefore, B must apply in real-life situation C.

Example: "I always win at chess, so I'd be a great military strategist."

Counter: Highlight the complexities and unpredictabilities of real-life situations.

Counter Example: "Real military strategy involves many more variables than chess, including logistics, diplomacy, and unpredictable human factors that can't be easily modeled in a game."

4. Base Rate Fallacy

Ignoring general probabilities in favor of specific, attention-grabbing information.

Formula: Ignore the base rate of A occurring, focus on specific instance B.

Example: Overestimating the risk of a rare disease due to a recent news story, despite its low prevalence in the population.

Counter: Present the absolute numbers and overall probabilities.

Counter Example: "While the news story is concerning, let's look at the actual prevalence of this disease in the population. Statistically, other health issues might be more relevant for most people."

5. Magical Thinking

Believing that one's thoughts or actions can influence unrelated events.

Formula: Action or thought A occurred before unrelated event B, so A must have caused B.

Example: "I wore my lucky socks and aced the test. My socks must have brought me good luck."

Counter: Request scientific evidence for the proposed causal relationship.

Counter Example: "Can you explain how wearing specific socks could influence test performance? Is there any scientific evidence supporting this kind of influence on cognitive abilities?"