Informal fallacies. Avoid being manipulated with language.

Informal fallacies: How the mind plays tricks on us with flawed arguments

Have you ever found yourself in the middle of an argument thinking, “That sounds good, but something doesn’t add up”? Congratulations, you’ve probably just stumbled upon a logical fallacy.

Informal fallacies are like faulty mental shortcuts that we pass off as valid arguments. They seem compelling, they sound logical… until you take them apart. And here’s the kicker: our brains love stories that reinforce our beliefs, even if they’re poorly founded. This is what makes fallacies powerful weapons in political debates, social media, and even dinner table conversations.

Why do we fall into fallacies?

Fallacies are the “fast food” of logic: quick, satisfying, and harmful if we abuse them. We often resort to fallacies for several reasons:

• Mental economy: Our brain loves to save energy. Thinking deeply requires effort, and sometimes we prefer what is easy.
• Emotions in charge: When a statement makes us feel validated or attacked, it is easier to fall into faulty reasoning.
• Herd effect: If everyone believes it, it must be true, right?

The most common fallacies, with their good examples

1. Ad Hominem Fallacy (personal attack)

👉 Example:

“You can’t trust what Javi says about science, he’s an influencer, not a scientist!”

🧠 Why it is incorrect:

Instead of analyzing Javi's arguments, his personal credibility is attacked. Even if Javi were a part-time clown, his opinion could be valid if he has well-founded arguments.

🎯 Why it works:

We love to associate the message with the messenger. If we distrust a person, we automatically assume that what they say is worthless. It is a quick and emotional mechanism to “discard” information.

2. Ad Populum Fallacy (appeal to the majority)

👉 Example:

“Everyone knows that Florentino Pérez is a mobster and corrupt.”

🧠 Why it is incorrect:

Just because a lot of people believe something doesn't mean it's true. Truth isn't a matter of democracy; it's a matter of evidence.

🎯 Why it works:

We feel safer following the crowd. If “everyone” believes it, we are less likely to question the claim out of fear of isolation, because we don’t want to realize we’ve always had an incorrect thought, or because we feel more comfortable buying into arguments rather than thinking for ourselves.

3. Fallacy of false cause (post hoc, ergo propter hoc)

👉 Example:

“Since the current government came to power, inflation has increased. They are useless!”

🧠 Why it is incorrect:

Even though the rise to power and the increase in inflation occurred in the same period, this does not automatically mean that there is a cause-and-effect relationship. Inflation can depend on global factors, such as international crises, energy price increases or monetary policies of the European Central Bank, which are not always under the control of the government.

Just because something happens after something else doesn't mean one causes the other. Correlation does not imply causation.

🎯 Why it works:

Our brains are constantly looking for patterns. Associating cause and effect is one of our favorite evolutionary tools, but sometimes it draws the wrong conclusions. In politics, we look for immediate culprits for complex problems because it is easier to blame the ruling party than to analyze external variables. This simplified narrative is very attractive because it feeds our emotions and confirms our expectations, especially if we do not sympathize with the government in question.

4. Fallacy of the false dichotomy (either black or white)

👉 Example:

“Either you are a Madrid fan or you are anti-Madrid. There is no middle ground.”

🧠 Why it is incorrect:

The situation is presented as if there are only two mutually exclusive options: being a Real Madrid fan or a hater. But the reality is much more complex. You can enjoy football, be neutral or even support several teams without taking radical sides.

🎯 Why it works:

Simplifying things makes us feel more comfortable. Grays are complex and force us to think more. Choosing between A or B is easier than considering an infinite scale of grays.

We also love belonging to “tribes” because it gives us a sense of identity and belonging. In football, these emotional divisions are very powerful, and simplifying the stances creates a stronger and easier-to-follow narrative: the “good guys” versus the “bad guys.”

5. Fallacy of appeal to authority

👉 Example:

“This car must be good because it is recommended by a Formula 1 driver.”

🧠 Why it is incorrect:

Just because a professional driver recommends a car doesn't mean it's the best choice for you. Street cars have different evaluation criteria than racing cars, such as comfort, fuel economy or everyday safety. A great driver may be an expert at driving cars, but that doesn't make him an impartial evaluator or an expert in all vehicle categories.

🎯 Why it works:

We tend to believe that successful people in a field have extensive knowledge on any related topic. Moreover, advertising and marketing take advantage of this emotional association to make their message more persuasive. If we admire the pilot, we automatically trust his opinion, even if it is not always well-founded.

6. Straw man fallacy

👉 Example:

“Are you in favor of electric cars? I bet you also want to ban all gasoline cars tomorrow and force us to plug in our cars in the middle of the road!”

🧠 Why it is incorrect:

The person who supports electric cars probably didn't say anything about banning gasoline cars outright or about absurd situations like running out of power in the middle of the highway. The original position has been exaggerated to make it seem impractical or absurd.

🎯 Why it works:

It is much easier to win an argument against an absurd argument than against a real one. It is a quick way to discredit the other person without responding to what they actually said.

Ridiculing a position makes it easier to attack and diverts attention from the real arguments. It also creates a humorous or dramatic component that appeals to the fear of change, reinforcing resistance to reasoned debate.

7. Slippery slope fallacy

👉 Example:

“If we legalize marijuana, soon everyone will end up using hard drugs.”

🧠 Why it is incorrect:

It assumes that an event will inevitably lead to a chain of increasingly worse consequences, without evidence to support this. It does not show that one step leads to the next.

🎯 Why it works:

The fear of the “domino effect” makes us avoid risks. It is an evolutionary bias: it is better to prevent a danger than to deal with its consequences, even if they are imaginary.

8. Special pleading fallacy

👉 Example:

“Scientists don't understand that the Earth is flat because they are indoctrinated by the system and only those who have awakened can see the truth.”

🧠 Why it is incorrect:

Here a “special exception” to scientific knowledge is created by claiming that only an “awake” or “enlightened” group can understand the supposed truth. Instead of providing verifiable evidence, criticism is discredited by arguing that others are “blinded” or “manipulated.” This makes the belief unquestionable because any objection is automatically attributed to the critic’s lack of understanding.

🎯 Why it works:

Appealing to exclusive or secret knowledge creates a sense of superiority and belonging to a special elite. It also creates a psychological barrier against rational dialogue: those who do not “believe” do so not because the argument is weak, but because they are “not prepared” to see it. This reinforces the idea that questioning the position is a sign of ignorance or indoctrination.

9. Ad Antiquitatem Fallacy (appeal to tradition)

👉 Example:

“Bullfighting should continue to be celebrated because it is a tradition with centuries of history in Spain.”

🧠 Why it is incorrect:

Just because something has been done for a long time doesn't mean it's right or should continue. Traditions may have cultural value, but that doesn't make them immune to change or ethical criticism. Arguing that something should be maintained just because it's old ignores the current context and new social values.

🎯 Why it works:

Traditions connect us to our roots and give us a sense of identity and belonging. The idea of ​​“breaking with the old” can provoke rejection because it makes us feel like we are losing something valuable or betraying our heritage. That is why appealing to antiquity is often an emotionally effective way to stop change.

10. Ad Nauseam Fallacy (appeal to repetition)

👉 Example:

“A lie repeated a thousand times becomes the truth.” — Quote attributed to Joseph Goebbels, Nazi propaganda minister.

🧠 Why it is incorrect:

Repeating a statement many times does not make it true, it just makes it more familiar and therefore easier for people to accept. During the Nazi regime, constantly repeated lies were used to manipulate public perception, such as the idea that certain groups were responsible for Germany’s economic and social problems. The insistence on these messages created a sense of “reality” in the population, even without foundation.

🎯 Why it works:

The human brain has a cognitive bias called the illusory truth effect: we tend to believe something is true simply because we have heard it many times. Familiarity breeds comfort, and comfort causes us to lower our critical defenses. Repetition thus becomes a very powerful tool for reinforcing beliefs, even when they are false.

11. Ad Verecundiam Fallacy (Appeal to Authority)

👉 Example:

“Albert Einstein said that God does not play dice, so quantum physics must be wrong.”

🧠 Why it is incorrect:

The fact that Einstein, a recognised genius, expressed his scepticism about randomness in quantum physics does not mean that the theory is wrong. The validity of a scientific claim depends on evidence and experiments, not on the personal opinion of an expert, however prestigious he may be. In fact, quantum physics has been confirmed on multiple occasions since Einstein's time.

🎯 Why it works:

We tend to trust authority figures and associate their prestige with infallibility. Invoking a great thinker or expert can create the illusion that an argument is irrefutable. However, even great minds can be wrong or limited by the knowledge of their time, and that does not invalidate later advances.

12. Ad Silentio Fallacy (appeal to silence)

👉 Example:

“If no one in this room has any objections, it means that everyone agrees with me.”

🧠 Why it is incorrect:

The fact that no one speaks up does not automatically mean that there is consensus. Silence can be due to many reasons: fear of retaliation, disinterest, lack of information or simply because people prefer not to express their opinion at that moment. Assuming that silence implies approval is flawed reasoning.

🎯 Why it works:

We associate silence with conformity because we have a hard time interpreting the lack of communication. Furthermore, in group situations, many people avoid speaking out so as not to stand out or create conflict, which reinforces the false perception of general agreement. This type of fallacy is particularly effective in hierarchical contexts, where authority figures often impose their narrative in the absence of responses.

13. Ad Ignorantiam Fallacy (appeal to ignorance)

👉 Example:

“5G has not been proven not to cause disease, so it is certainly harmful to health.”

🧠 Why it is incorrect:

The absence of evidence showing that 5G is not dangerous does not automatically mean that it is. The burden of proof is on those who claim that it is harmful, not on those who need to continually prove that it is not. So far, scientific studies indicate that the radio frequency waves used by 5G are safe within regulated limits.

🎯 Why it works:

New technologies often generate distrust, and uncertainty lends itself to speculation. This fallacy exploits the fear of the unknown and takes advantage of the lack of absolute proof as “confirmation” of a non-existent danger, playing on the human need for certainty and the fear of possible hidden risks.

How to train our “fallacy detector”?

The best defense is critical curiosity:
1. Identify shortcuts: If something sounds too simple to be true, it probably is.
2. Ask questions: Does the argument really answer the question or did it stray into something else?
3. Challenge the emotion: When something really bothers you, ask yourself: Is it manipulating me or informing me?

Conclusion

Informal fallacies are like optical illusions of thought: when you detect them, you begin to see reality more clearly, and we stop being victims of those invalid arguments. So, the next time someone throws at you an argument that seems solid but smells like a trap, stop and observe. Because, in the end, logic is like science: it needs evidence, not opinions disguised as truth.

"Science teaches us not to believe something just because it is comforting, but to seek the truth, no matter how uncomfortable it may be."

Carl Sagan