Everything is Obvious summary

For individuals, common sense is useful for weighing the problems of the day-to-day: it helps us fit in and follow society’s rules. But common sense begins to fail when dealing with larger problems that affect entire societies.

The decisions of decision-makers, such as politicians, social scientists, planners, etc., are often based on common sense, which results in huge mistakes.

It is common for people to be organ donors in many countries in the world. But the number of people who choose to donate varies dramatically across different countries. For example, over the span of one year, 12 percent of Germans agreed to be organ donors compared to an unbelievable 99.9 percent in neighboring Austria. Why is this?

The answer is quite simple: in Austria, the default choice is to be an organ donor, whereas in Germany it isn’t!

The Mona Lisa is considered to be one of the most important works of art in Western culture, but why? What makes it so special? Aren’t there many other paintings that are just as good? Try this: take a moment and list the reasons why the Mona Lisa is so important. What have you come up with?

You probably formed your answers using circular reasoning, a logical fallacy informed by our common sense. Circular reasoning is a fallacy because it uses the conclusion to justify itself, rather than using evidence to produce a conclusion.

You’re probably familiar with the phrase six degrees of separation, but you might not know where it comes from.

The phrase became popular after a psychological experiment conducted by Stanley Milgram in 1967, involving 300 people. He found that if someone tried to pass a message to a friend by first handing it to a stranger, it took six connections on average for the message to finally arrive.

Many of us have a great interest in history; we enjoy learning about historical events and trying to piece together what happened in times past. But, unfortunately, once again our common sense obscures our view and understanding of the past.

When we look at a sequence of historical events, common sense leads us to believe that one event caused the next, even though the link might remain unproven.

Experts in the financial sector often seem quite sure of their predictions for the future: “invest in this,” they tell us, “and you’ll make millions!”

Yet so often things don't go as planned, and those who follow the experts’ advice can lose big. In spite of this, these “experts” continue making predictions!

So we now know that there are certain kinds of predictions we’d like to make, but ultimately can’t. But surely this doesn’t mean we can’t predict anything at all! Poker players, for example, seem quite good at betting on whether they have better cards than their opponents.

So how, then, can we make predictions?

Each year the fashion industry devotes a great amount of time and energy to trying to predict what people will be wearing the following year. But no one seems to check whether any of these predictions actually come true! It certainly makes you wonder: if you want to run a successful fashion company, then maybe you shouldn’t even bother paying attention to these predictions at all.

As it turns out, the Spanish clothing retailer Zara does precisely that with their “measure-and-react strategy.”

If a sleepy driver accidentally runs over a child on his way home from work, common sense demands that we condemn him to prison. Yet had the child not been there, our attitude toward this person would not be nearly as harsh. Can you imagine sending every sleepy driver to prison on the grounds that they might kill someone?

So how do we account for this discrepancy?

In physics, we have been able to come up with general theories like gravity thanks to centuries of sustained research. However, when it comes to human behavior, our thinking is still riddled with mistakes, and some sociologists even believe that grand social theories are not useful for understanding complex human interactions.

How, then, can we hope to grow our understanding of human behavior?

The key message in this book:

Common sense, while often useful in our day-to-day lives, fails us when we grapple with complex problems with many actors and perspectives. By understanding the pitfalls of common sense and adopting better strategies, we can improve the way we plan for the future and understand the present.