The pope asked Michelangelo: “Tell me the secret of your genius. How have you created the statue of David, the masterpiece of all masterpieces?” Michelangelo’s answer: “It’s simple. I removed everything that is not David.”
Let’s be honest. We don’t know for sure what makes us successful. We can’t pinpoint exactly what makes us happy. But we know with certainty what destroys success or happiness. This realization, as simple as it is, is fundamental: Negative knowledge (what not to do) is much more potent than positive knowledge (what to do).
Thinking more clearly and acting more shrewdly means adopting Michelangelo’s method: Don’t focus on David. Instead, focus on everything that is not David and chisel it away. In our case: Eliminate all errors and better thinking will follow.
The Greeks, Romans, and medieval thinkers had a term for this approach: via negativa. Literally, the negative path, the path of renunciation, of exclusion, of reduction. Theologians were the first to tread the via negativa: We cannot say what God is; we can only say what God is not. Applied to the present day: We cannot say what brings us success. We can pin down only what blocks or obliterates success. Eliminate the downside, the thinking errors, and the upside will take care of itself. This is all we need to know.
As a novelist and company founder, I have fallen into a variety of traps. Fortunately I was always able to free myself from them. Nowadays when I hold presentations in front of doctors, CEOs, board members, investors, politicians, or government officials, I sense a kinship. I feel that we are sitting in the same boat—after all, we are all trying to row through life without getting swallowed up by the maelstroms. Still, many people are uneasy with the via negativa. It is counterintuitive. It is even countercultural, flying in the face of contemporary wisdom. But look around and you’ll find plenty of examples of the via negativa at work. This is what the legendary investor Warren Buffett writes about himself and his partner Charlie Munger: “Charlie and I have not learned how to solve difficult business problems. What we have learned is to avoid them.” Welcome to the via negativa.
I have listed almost one hundred thinking errors in this book without answering the question: What are thinking errors anyway? What is irrationality? Why do we fall into these traps? Two theories of irrationality exist: a hot and a cold. The hot theory is as old as the hills. Here is Plato’s analogy: A rider steers wildly galloping horses; the rider signifies reason and the galloping horses embody emotions. Reason tames feelings. If this fails, irrationality runs free. Another example: Feelings are like bubbling lava. Usually, reason can keep a lid on them, but every now and then the lava of irrationality erupts. Hence hot irrationality. There is no reason to fret about logic: It is error-free; it’s just that, sometimes, emotions overpower it.
This hot theory of irrationality boiled and bubbled for centuries. For John Calvin, the founder of a strict form of Protestantism in the 1500s, such feelings represented evil, and only by focusing on God could you repel them. People who underwent volcanic eruptions of emotion were of the devil. They were tortured and killed. According to Austrian psychoanalyst Sigmund Freud’s theory, the rationalist “ego” and the moralistic “superego” control the impulsive “id.” But that theory holds less water in the real world. Forget about obligation and discipline. To believe that we can completely control our emotions through thinking is illusory—as illusory as trying to make your hair grow by willing it to.
On the other hand, the cold theory of irrationality is still young. After the Second World War, many searched for explanations about the irrationality of the Nazis. Emotional outbursts were rare in Hitler’s leadership ranks. Even his fiery speeches were nothing more than masterful performances. It was not molten eruptions but stone-cold calculation that resulted in the Nazi madness. The same can be said of Stalin or of the Khmer Rouge.
In the 1960s, psychologists began to do away with Freud’s claims and to examine our thinking, decisions, and actions scientifically. The result was a cold theory of irrationality that states: Thinking is in itself not pure, but prone to error. This affects everyone. Even highly intelligent people fall into the same cognitive traps. Likewise, errors are not randomly distributed. We systematically err in the same direction. That makes our mistakes predictable, and thus fixable to a degree—but only to a degree, never completely. For a few decades, the origins of these errors remained in the dark. Everything else in our body is relatively reliable—heart, muscles, lungs, immune system. Why should our brains of all things experience lapse after lapse?
Thinking is a biological phenomenon. Evolution has shaped it just as it has the forms of animals or the colors of flowers. Suppose we could go back fifty thousand years, grab hold of an ancestor, and bring him back with us into the present. We send him to the hairdresser and put him in a Hugo Boss suit. Would he stand out on the street? No. Of course, he would have to learn English, how to drive, and how to operate a cell phone, but we had to learn those things, too. Biology has dispelled all doubt: Physically, and that includes cognitively, we are hunter-gatherers in Hugo Boss (or H&M, as the case may be).
What has changed markedly since ancient times is the environment in which we live. Back then, things were simple and stable. We lived in small groups of about fifty people. There was no significant technological or social progress. Only in the last ten thousand years did the world begin to transform dramatically, with the development of crops, livestock, villages, cities, global trade, and financial markets. Since industrialization, little is left of the environment for which our brain is optimized. If you spend fifteen minutes in a shopping mall, you will pass more people than our ancestors saw during their entire lifetimes. Whoever claims to know how the world will look in ten years is made into a laughingstock less than a year after such a pronouncement. In the past ten thousand years, we have created a world that we no longer understand. Everything is more sophisticated, but also more complex and interdependent. The result is overwhelming material prosperity, but also lifestyle diseases (such as type 2 diabetes, lung cancer, and depression) and errors in thinking. If the complexity continues to rise—and it will, that much is certain—these errors will only increase and intensify.
In our hunter-gatherer past, activity paid off more often than reflection did. Lightning-fast reactions were vital, and long ruminations were ruinous. If your hunter-gatherer buddies suddenly bolted, it made sense to follow suit—regardless of whether a saber-toothed tiger or a boar had startled them. If you failed to run away, and it turned out to be a tiger, the price of a first-degree error was death. On the other hand, if you had just fled from a board, this lesser mistake would have cost you only a few calories. It paid to be wrong about the same things. Whoever was wired differently exited the gene pool after the first or second incidence. We are the descendants of those homines sapientes who tend to flee when the crowd does. But in the modern world, this intuitive behavior is disadvantageous. Today’s world rewards single-minded contemplation and independent action. Anyone who has fallen victim to stock market hype has witnessed that.
Evolutionary psychology is still mostly a theory, but a very convincing one at that. It explains the majority of flaws, though not all of them. Consider the following statement: “Every Hershey bar comes in a brown wrapper. Thus, every candy bar in a brown wrapper must be a Hershey bar.” Even intelligent people are susceptible to this flawed conclusion—so are native tribes that, for the most part, remain untouched by civilization. Our hunter-gatherer ancestors were certainly not impervious to faulty logic. Some bugs in our thinking are hardwired and have nothing to do with the “mutation” of our environment.
Why is that? Evolution does not “optimize” us completely. As long as we advance beyond our competitors (i.e., beat the Neanderthals), we can get away with error-laced behavior. Consider the cuckoo: For hundreds of thousands of years, they have laid their eggs in the nests of songbirds, which then incubate and even feed the cuckoo chicks. This represents a behavioral error that evolution has not erased from the smaller birds; it is not deemed to be serious enough.
A second, parallel explanation of why our mistakes are so persistent took shape in the late 1990s: Our brains are designed to reproduce rather than search for the truth. In other words, we use our thoughts primarily to persuade. Whoever convinces others secures power and thus access to resources. Such assets represent a major advantage for mating and for rearing offspring. That truth is, at best, a secondary focus and is reflected in the book market: Novels sell much better than nonfiction titles, in spite of the latter’s superior candor.
Finally, a third explanation exists: Intuitive decisions, even if they lack logic, are better under certain circumstances. So-called heuristic research deals with this topic. For many decisions, we lack the necessary information, so we are forced to use mental shortcuts and rules of thumb (heuristics). If you are drawn to different potential romantic partners, you must evaluate whom to marry. This is not a rational decision; if you rely solely on logic, you will remain single forever. In short, we often decide intuitively and justify our choices later. Many decisions (career, life partner, investments) take place subconsciously. A fraction of a second later, we construct a reason so that we feel we made a conscious choice. Alas, we do not behave like scientists who are purely interested in objective facts. Instead, we think like lawyers, crafting the best possible justification for a predetermined conclusion.
So, forget about the “left and right brain” that semi-intelligent self-help books describe. Much more important is the difference between intuitive and rational thinking. Both have legitimate applications. The intuitive mind is swift, spontaneous, and energy-saving. Rational thinking is slow, demanding, and energy-guzzling (in the form of blood sugar). Nobody has described this better than the great Daniel Kahneman in Thinking, Fast and Slow.
Since I started to collect cognitive errors, people often ask me how I manage to live an error-free life. The answer is: I don’t. In fact, I don’t even try. Just like everybody else, I make snap decisions by consulting not my thoughts but my feelings. For the most part I substitute the question “What do I think about this?” with “How do I feel about this?” Quite frankly, anticipating and avoiding fallacies is a costly undertaking.
To make things simple, I have set myself the following rules: In situations where the possible consequences are large (i.e., important personal or business decisions), I try to be as reasonable and rational as possible when choosing. I take out my list of errors and check them off one by one, just like a pilot does. I’ve created a handy checklist decision tree, and I use it to examine important decisions with a fine-tooth comb. In situations where the consequences are small (i.e., regular or Diet Pepsi, sparkling or flat water?), I forget about rational optimization and let my intuition take over. Thinking is tiring. Therefore, if the potential harm is small, don’t rack your brains; such errors won’t do lasting damage. You’ll live better like this. Nature doesn’t seem to mind if our decisions are perfect or not, as long as we can maneuver ourselves through life—and as long as we are ready to be rational when it comes to the crunch. And there’s one other area where I let my intuition take the lead: when I am in my “circle of competence.” If you practice an instrument, you learn the notes and tell your fingers how to play them. Over time, you know the keys or the strings inside out. You see a musical score and your hands play the notes almost automatically. Warren Buffett reads balance sheets like professional musicians read scores. This is his circle of competence, the field he intuitively understands and masters. So, find out where your circle of competence is. Get a clear grasp of it. Hint: It’s smaller than you think. If you face a consequential decision outside that circle, apply the hard, slow, rational thinking. For everything else, give your intuition free rein.