Book SummaryThe Art of Thinking Clearly, by Rolf Dobelli

1-Page Summary1-Page Book Summary of The Art of Thinking Clearly

The Art of Thinking Clearly is an introduction to the most common logical fallacies that affect people’s ability to make good decisions. Logical fallacies affect everyone and are extremely difficult to avoid. Rolf Dobelli encourages readers to improve their decisions by learning how to recognize the fallacies and how to work around them.

Dobelli warns that his book isn't a step-by-step guide to logical thinking. Rather, he takes the “via negativa” approach, explaining what prevents you from thinking logically. If you’re aware of your illogical tendencies, you can work around them and make good decisions.

In this guide, we’ll explore the most common logical fallacies, grouping them by theme. We’ll start with fallacies caused by evolutionary adaptations and move to fallacies with more varied causes. We’ll cover how these fallacies form and how to overcome them.

You Want to Belong to the Group

First, we’ll cover fallacies related to group membership. Dobelli says that one of the traits that most influences you is the desire to be in a group. For early humans, group membership was necessary for survival. Those who left the group died, while those who stayed with the group survived and reproduced. Thus, your brain is genetically wired to fit in.

(Shortform note: The physical protection groups once offered has become less important, but group membership is still valuable to modern humans: It exposes you to others’ experiences and life skills and helps you develop empathy and self-worth.)

In this section, we’ll cover some of the specific ways this desire to be in a group impacts you.

Social Proof and Authority Bias

To maintain your place in a group, you’re pressured to copy other people’s behavior, especially if that person is an authority. This pressure can even convince you to ignore your morals, Dobelli says.

(Shortform note: It’s hard to resist pressure from authorities because you’re trained from childhood to obey them. You can make this pressure easier to resist by distancing yourself from the authority and forming a connection with any victims of the problematic actions you’re being pressured into.)

In-Group, Out-Group Bias

Another consequence of group membership is prioritizing your own group above others. Your brain focuses on similarities between you and your group members, Dobelli says, ignoring any differences. Your brain also simplifies other groups, labeling them as “other” and ignoring any similarities you share with them. Finally, you think your group is the best because you only spend time with your group and don’t hear any different opinions.

(Shortform note: You prioritize your in-group because group membership becomes part of your identity: Protecting your group becomes protecting your identity. However, pinning your identity on membership of an in-group is dangerous, because in-groups can change depending on the situation—you may find yourself no longer a member of the group you value and feel unsure of your identity. You can avert this by increasing the variety of your groups so you don't tie yourself too closely to just one. Spend time with people from different groups, focus on points of connection with others rather than differences, and recognize when your groups are formed around arbitrary means that could crumble.)

You Pay Attention to the Wrong Things

Now that we've covered biases relating to humanity’s desire to fit in, we’ll examine fallacies that misdirect your attention. Humans tend to pay attention to the most memorable or flashy information that comes up, rather than the most pertinent or helpful, Dobelli explains. (Shortform note: The brain has arguably evolved to do this for reasons of efficiency. Your brain rapidly stores information, and it takes it less time and energy to accept the flashiest information available than to evaluate the entire situation.)

Here are some of the ways in which your attention is drawn to the wrong things:

The Salience Effect

According to Dobelli, when the salience effect takes hold, your brain latches onto unusual or notable factors of a situation and gives them too much credit for causing the situation, ignoring any more subtle influences. (Shortform note: What you pay attention to when the effect sets in depends on your past experiences. You might notice certain details due to your career or past experiences while someone else would notice different things. Thus, surrounding yourself with people with varied experiences can give you a clearer idea of the whole situation, as you can compare notes on the different things you’ve noticed.)

Story Bias

Another way people’s attention is misdirected is through story bias. People prefer entertaining fiction to boring facts, Dobelli explains. Sometimes, this means following an interesting story-based tangent while ignoring the central issue; other times, it means assigning meaning to random events.

(Shortform note: Why do we do this? Possibly because stories activate your brain’s sensory processing center. This gives you a...

The Art of Thinking Clearly Summary Shortform Introduction

In The Art of Thinking Clearly, Rolf Dobelli breaks down the most common logical fallacies that plague humanity. Logical fallacies affect everyone, are extremely difficult to avoid, and can hinder our decision-making ability. Dobelli encourages readers to improve their decisions by learning how to recognize these fallacies and how to work around them.

About the Author

Rolf Dobelli is a Swiss writer and entrepreneur. Born in Lucerne, Switzerland, in 1966, Dobelli studied philosophy and business administration at college. He graduated with an MBA and PhD in philosophy from the University of St. Gallen, Switzerland in 1995.

Dobelli primarily wrote novels before stepping into non-fiction in 2011. The Art of Thinking Clearly was his first non-fiction book, and he hadn’t always intended to publish it. The book was originally a private list of fallacies he’d curated to help himself act logically. It was only after friends expressed interest in the list that he started publishing it in newspaper columns and eventually as a book.

Once it was published, The Art of Thinking Clearly catapulted Dobelli to...

The Art of Thinking Clearly Summary Part 1: Evolutionary Fallacies | Chapter 1: You Want to Belong to the Group

In The Art of Thinking Clearly, Rolf Dobelli explores 99 common fallacies that inhibit logical thinking. He explains how these fallacies form and how they can negatively affect your daily decision-making.

Dobelli warns that his book isn't a step-by-step guide to logical thinking. Rather, he takes the “via negativa” approach, explaining what prevents you from thinking logically. If you’re aware of your illogical tendencies, you can work around them and make good decisions.

In Part 1 of this guide, we’ll cover evolutionary fallacies: traits stemming from humanity’s past as hunter-gatherers. In Part 2, we’ll cover non-evolutionary fallacies: traits stemming from other sources.

What Are Evolutionary Fallacies?

According to Dobelli, evolutionary fallacies are errors in thinking that occur because of the way humans’ brains evolved over millions of years. Through evolution, humans’ thought processes were optimized for a hunter-gatherer lifestyle. As we’ll see, in the modern industrialized world, these lingering thought patterns become pitfalls rather than benefits.

Evolutionary Psychology: How It Works and Why You’re Not Evolving Anymore

Dobelli’s...

Shortform Exercise: Overcome Social Proof

According to Dobelli, social proof pressures you to copy other people’s behavior. This is a defense mechanism to maintain your group membership, but it can lead you to make bad decisions. Every person has unique wants and needs, and following the status quo might keep you from happiness.

Think of the last time you did something because you felt pressured to by your group. (This group could be family members, friends, religious or political groups, and so on.) What happened? Did your actions make you happy or unhappy, and why?

The Art of Thinking Clearly Summary Chapter 2: You Pay Attention to the Wrong Things

Now that we've covered biases relating to humanity’s desire to fit in, we’ll examine the next set of evolutionary fallacies: those in which you pay attention to the wrong things. Humans have evolved to pay attention to the most memorable or flashy information that comes up, rather than the most pertinent or helpful, Dobelli explains. The more conspicuous and repeated a piece of information is, the more you’ll believe it.

(Shortform note: The brain has arguably evolved to do this for reasons of efficiency. Your brain rapidly stores information, and it takes it less time and energy to accept the flashiest information available than to evaluate the entire situation. This is especially true in the modern day, when you’re constantly bombarded with information from, for instance, social media.)

In this chapter, we’ll cover the following fallacies:

• The salience effect
• Story bias
• Survivorship bias
• False knowledge
• The feature-positive effect
• The illusion of attention

The Salience Effect

The first attention-affecting fallacy we’ll look at is the salience effect. Dobelli notes that **your brain...

Shortform Exercise: Overcome the Illusion of Attention

The illusion of attention makes people think they’re paying attention to everything around them, when really, their brain discards many details it deems unimportant. You can overcome this illusion by challenging your expectations and assumptions of your situation.

Describe a situation where you thought you were paying attention to everything but were later surprised by something you missed. (This could be someone reacting differently than you anticipated or a decision having unexpected consequences.)

The Art of Thinking Clearly Summary Chapter 3: You’re Using the Wrong Kind of Thinking

The next set of fallacies we'll look at revolve around using the wrong type of thinking. There are two main kinds of thinking: fast and instinctive, and slow and logical. Both play important roles, Dobelli explains, but both cause logical fallacies when used in the wrong situation. (Shortform note: These types of thinking are also called hot and cold cognition. Instinct and emotion dictate hot cognition, while logic and reasoning control cold cognition. Hot cognition uses little mental energy, doesn’t turn off, and inspires impulsive decisions, while cold cognition uses a lot of mental energy and can overwhelm you with information.)

So when is it better to rely on fast, instinctive thinking? When actions are familiar or something you’ve been evolutionarily optimized for, Dobelli says. If you’ve ever thought too hard about the way you’re breathing, you’re using slow thinking when instinctive thinking is better. When you’re trying something new, or are in a situation you’re not instinctually prepared for, use slow logic, Dobelli concludes.

**Other Perspectives on When and How to Think...

Shortform Exercise: Overcome the Affect Heuristic

Affects are immediate judgments of like or dislike. Your brain makes these very quickly and relies on these affects rather than logical risk-benefit analyses. It’s important to overcome the affect heuristic because these instinctive judgments aren’t always accurate.

Identify three instinctive judgments of objects or actions that influence your behavior. (Common affects include seeing sugary treats as better than healthy food, seeing intimidating items as more dangerous than they are, such as nuclear power plants, or seeing attractive items as more beneficial than they are, such as motorcycles.)

The Art of Thinking Clearly Summary Chapter 4: You Struggle to Understand Complex Math

The next set of fallacies we’ll look at revolve around complex math. Your hunter-gatherer brain isn’t designed for complex math, Dobelli says: Because your ancestors didn’t need this math to survive, you can’t instinctively grasp concepts like averages, statistics, and exponential growth. However, understanding these concepts is important for modern life.

(Shortform note: Some people argue that people’s difficulty with complex math concepts isn't a biological limitation but a result of how math is viewed. People internalize the idea that math is difficult and define themselves as “a math person” or “not a math person.” Thus, those who struggle with math concepts stop trying to understand them. If people treated math like a second language, which takes a lot of practice and repetition to learn but can be learned by anyone, people would learn complex math easier.)

In this chapter, we’ll look at the following examples of complex math concepts and how not understanding them...

The Art of Thinking Clearly Summary Chapter 5: Miscellaneous Evolutionary Fallacies

Now that we’ve covered the main groups of evolutionary fallacies, we’ll look at the following final, miscellaneous fallacies of this kind:

• Ambiguity aversion
• Action bias
• Loss aversion

Ambiguity Aversion

According to Dobelli, ambiguity aversion is the human tendency to dislike uncertainty. Uncertainty is a lack of concrete facts about an outcome. For early humans, lacking facts was deadly: If you didn’t know which plants were edible or where predators lived, you died. Thus, humans evolved to avoid uncertainty.

(Shortform note: Ambiguity aversion is the root of the colloquialism “Better the devil you know.” Even if your situation is bad, you’d rather stay in that situation than face the uncertainty of leaving. For example, say you’re stuck in a job you hate and are offered a new job in a field you know nothing about but might like—you’re not quite sure. Despite not enjoying your current job, you’ll probably choose to stay: Your fear of uncertainty over the new job makes you choose the unhappiness you know.)

However, **uncertainty is very prevalent and...

The Art of Thinking Clearly Summary Part 2: Non-Evolutionary Fallacies | Chapter 6: You Misinterpret Cause and Effect

Now that we’ve covered evolutionary fallacies, we’ll look at non-evolutionary fallacies. These are fallacies that Dobelli doesn’t classify as having an evolutionary basis: Rather, they have other causes, such as past experience, limited perspective, or information overload.

In this chapter, we’ll cover how misinterpreting cause and effect damages your judgment. According to Dobelli, humans struggle to interpret cause and effect because they confuse correlation and causation. When two events coincide, people assume there’s a causal relationship between the two of them, even when there’s not. For example, if a person gets the flu after they start taking vitamins, they might assume a causal relationship—taking vitamins gave them the flu—simply because the timing coincides.

(Shortform note: How do people make these mistaken links? They take their knowledge of the effect and look for any similar events that might point to a cause, regardless of the likelihood of that similar event actually being the cause. In...

Shortform Exercise: Overcome the Fallacy of the Single Cause

The fallacy of the single cause is the desire to simplify a situation until it has only one cause. This is problematic because everything is caused by a complex web of influences. You can use this knowledge of the web of influences to overcome the fallacy.

Describe a current project. Make a list of all potential influences on the success of that project.

The Art of Thinking Clearly Summary Chapter 7: Your Memory Is Not as Reliable as You Think It Is

In this chapter, we’ll look at fallacies related to memory. People believe their memories are untouchable, stored away and recalled when needed in perfect condition. However, this isn't the case, Dobelli warns. Your memory is affected by your feelings, opinions, and situation.

(Shortform note: Your memories are affected in these ways at several points: First, whatever you were feeling in a moment is tangled up with the details of the situation in your memory. Later, every time you remember the situation, your current mental state further alters your memories. Thus, the more you remember a situation, the more distorted the memory becomes.)

We’ll look at the following fallacies and situations in which your memory is unreliable:

• Falsification of history
• The Zeigarnik effect
• The primacy and recency effects

Falsification of History

The first and most serious situation that affects your memory is falsification of history. Your brain is constantly rewriting your memories, Dobelli explains. As your...

Shortform Exercise: Alleviate Stress With the Zeigarnik Effect

The Zeigarnik effect impacts how your brain handles tasks, Dobelli says. Before a task is completed, it stays in the forefront of your mind, often causing stress. Once you’ve completed the task, though, you forget it. You can manipulate this tendency to clear your mind of pressing tasks and alleviate stress.

Make a list of your three most pressing unfinished tasks that are clogging your mind and causing you stress.

The Art of Thinking Clearly Summary Chapter 8: You Struggle to Understand Probability and Predictions

The next set of fallacies we’ll cover revolves around probability and predictions. Dobelli reminds us that people hate uncertainty, and he says that they try to predict future events to reduce that uncertainty. However, to make accurate predictions, you must understand probability, which humans struggle with.

Thus, people’s predictions are usually inaccurate, even those from experts who make predictions for a living. Yet, despite their inaccuracy, people still rely on predictions to make important decisions, leading to logical errors and financial loss.

(Shortform note: As Dobelli notes, even though humans struggle with probability and predictions are unreliable, people still make a living estimating probability and making predictions. This is authority bias: Because the person is seemingly an expert at making predictions, you assume they know what they're doing. However, no matter how knowledgeable the person, [they’ll still struggle to process the information...

The Art of Thinking Clearly Summary Chapter 9: You Value Things for Arbitrary Reasons

In this chapter, we’ll cover fallacies that affect how you value things. According to Dobelli, humans tend to value a person, situation, or item for arbitrary and illogical reasons. We’ll look at the following arbitrary standards of value:

• The endowment effect
• Liking bias
• The sunk cost fallacy
• The contrast effect

The Endowment Effect

The endowment effect is the first illogical shift in your valuation of an item. When you own an item, you subconsciously increase its value simply because it's yours, Dobelli explains. (Shortform note: Dobelli doesn’t explain why the endowment effect occurs, but others argue that it stems from loss aversion, discussed in Chapter 5. Once something is in your possession, you fear losing it, which makes you value the item more.)

The endowment effect makes buying and selling things difficult, Dobelli adds, because you inflate the value of an item to be higher than others value it. You’ll even turn down generous offers for the item because you’ve mistakenly increased its value so much.

The endowment effect also influences people who don’t own an item yet, Dobelli...

Shortform Exercise: Overcome the Sunk Cost Fallacy

The sunk cost fallacy means that the more you invest in something, the more you value that thing. This means you’ll hold onto things you’ve heavily invested in beyond their usefulness. You can overcome the sunk cost fallacy by focusing on the future benefits or consequences keeping that activity or item would bring.

Describe something you’ve been investing in. (It could be a hobby, a business, stocks, or anything that takes time, money, or effort.)

The Art of Thinking Clearly Summary Chapter 10: You Have Too Much of a Good Thing

Our next set of fallacies revolve around situations in which you have too much of a good thing. Many times, you make bad decisions because you don’t have enough options, information, or experience to make logical ones. However, too many options, information, or experience can also inspire irrational decisions, Dobelli says.

In this chapter, we’ll look at the following situations where excess causes irrationality:

• Too many options
• Too much information
• Too much experience

Too Many Options

The first situation we’ll cover is having too many options. Most people think that having more options to choose from is better than having fewer, Dobelli says. However, having too many options can be just as bad as not having enough for three reasons:

1. Having too many options paralyzes you. A wide range of options makes you so afraid of choosing the wrong one that you avoid any decision, Dobelli says. (Shortform note: Some people tie this paralysis to loss aversion, discussed in Chapter 5. The more options available, the more options you lose by choosing. You fear losing the other options more...

The Art of Thinking Clearly Summary Chapter 11: Miscellaneous Non-Evolutionary Fallacies

Now that we’ve looked at the major types of non-evolutionary fallacies, we’ll look at the following final miscellaneous fallacies:

• Confirmation bias
• Omission bias
• Alternative bias
• Incentive manipulation
• Planning fallacy

Confirmation Bias

When you suffer from confirmation bias, you retain information that reinforces your underlying beliefs or desired conclusions while ignoring contradicting evidence. Everyone has a tendency toward confirmation bias, Dobelli warns.

(Shortform note: Here, Dobelli references both underlying beliefs and desired conclusions. While confirmation bias can reinforce both, your underlying beliefs ultimately overpower your desires. For example, an anxious individual might desire confidence in their friends, but they believe their friends dislike them. Their confirmation bias takes neutral interactions and uses them as evidence to reinforce this belief, ignoring their desire.)

Some people manipulate others’ natural tendency toward confirmation bias, Dobelli adds. Fortune tellers, for example, give vague statements, trusting that your...