Summary of The Black Swan by Nassim Taleb

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  • Post last modified:August 18, 2022
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Short summary: 3 min

Long summary: 30 min

Book reading time: 10h26

Score: 8/10

Book published in: 2007

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Takeaway

  • Black Swans are events that have a big impact on a system and that could not be predicted because they’ve never happened before.
  • There are two types of randomness in life: one that welcomes Black Swans, and one that doesn’t.
  • If you want to win, find situations where the upside is big and the downside small. Bet everything on them.

What The Black Swan Talks About

The Black Swan is a book written by Nassim Taleb. It explains that there are two types of randomness in life: one where extreme random events don’t happen, and one where they do. These extreme events are called Black Swans. The book subsequently explores how to think about Black Swans in life and society.

The Black Swan is the second book of Taleb’s series called The Incerto, organized as follows.

The book came out in April 2007, when the first signs of the 2008 financial crisis were appearing. The nearly avoided bankruptcy of the Western financial system catapulted Taleb to the pinnacle of Anglo-Saxon intellectualism. He was received like a rock star at the 2009 World Economic Forum in Davos.

The Black Swan ended up selling at least 3 million copies and ironically became…a Black Swan.

Not going to lie, it’s a tough book. I read it at a pace of 7000 words per hour, or 116 words per minute, roughly half of my normal reading-while-summarizing pace. I had to re-read many of the sentences.

If you have never taken a statistics or finance class, google the terms you run across.

Most of the time, Nassim Taleb succeeds at conveying his message, yet some of the things he wrote were unclear – or I lacked the intellect to understand them.

The book was in essence really good because it teaches something no one else is teaching, and it does so in a way no one else does it in. But I am a bit disappointed – I was expecting more out of it, which does not make any sense!

Since a Black Swan cannot be predicted, it can hardly be talked about before it happens, an illogicality Taleb himself speaks about in the book.

The Black Swan is a fun book. Taleb tells you at the beginning that he had fun writing it, and you can definitely sense it.

If you are really into Nassim Taleb’s writing style and ideas, and if you have a lot of time on your hand, read the book. It will be great for your general knowledge.

But if you just want to get the gist, my extensive summary will suffice.

8/10.

Get the book here.


Short Summary

Situations in life are subject to two types of randomness: one that happens in “Mediocristan”, and one located in “Extremistan”.

Randomness in Mediocristan is concerned with situations where the overwhelming majority of units in a sample will constantly gravitate towards the mean. It means that one unit will never be able to influence the average.

Eg: the money you make as a massage therapist. Some therapists will make €10/hour in lower-income countries, and the highest-paid massage therapists in the world will likely make up to €500/hour. But they will never make €1 000 000/hour.

If you line up 100 random massage therapists, one massage therapist, even if he is paid super high, or super low, will never be able to influence the average made by the 99 others.

Earning money as a massage therapist is in Mediocristan.

If you take wealth, it’s a different story. If you take 100 random people and measure the average of their wealth, the average will definitely be perturbated if you add Elon Musk to the sample. One sample managed to disturb the average.

Wealth is therefore a matter existing in Extremistan.

Situations in Mediocristan won’t know any Black Swan. Situations in Extremistan, will. The point is to always know whether you are in an Extremistan situation, or a Mediocristan one.

People, due to internal biases, aren’t trained to make a difference between Mediocristan and Extremistan.

As a result, they get surprised when a Black Swan appears. A Black Swan is a random event of high impact and low probability. It mainly happens in Extremistan.

We cannot predict Black Swans for several reasons.

First, we predict our future based on our past. That prevents us from “seeing coming” events that never happened in the past. Eg: 9/11.

Second, we tend to look for evidence of things we already know instead of looking for where we could be wrong, for the unknown.

Third, we rationalize all events by embedding them into a narrative despite the fact that these events are random and have nothing to do with one another.

Fourth, we behave as if the Black Swan did not exist because our brain is hooked on routine and regularity.

Fifth, we ignore the silent pieces of evidence of phenomenons, taking into account only what happened, and leaving out what didn’t happen, or what we didn’t see happened.

Sixth, we tend to “tunnel” our knowledge and judgment by focusing on the detail, instead of focusing on the broader picture.

If you want to live your life well, look for asymmetric returns.

Go 100% into bets that have huge upside and no downside (eg: a job in a startup where you get equity), and be extremely careful and conservative with the rest, in order to mitigate the risks when the inevitable Black Swan hits.


Table of Content


Summary of The Black Swan Written by Nassim Taleb

Prologue

For millennials, people thought all swans were white. Until one black swan was spotted in Australia.

One bird was enough to disprove a belief made for centuries.

Following this logic, Black Swans are events that share three properties.

  1. Rarity: no one expects it because the past could not have predicted it.
  2. Extreme impact: It carries an extreme impact.
  3. Retrospective predictability: People say it could have been predicted after it happened.

The world evolved because of Black Swans. The agricultural revolution was a Black Swan, the Internet was a Black Swan, and WWI was a Black Swan too.

Black Swans are dangerous because they embody what you don’t know. Their impact is great because nobody expected them.

Consider the tsunami of 2004. If it had been expected, systems would have been put in place to prevent it.

In a way, a Black Swan is an event that happened, but was not supposed to – understand: we hadn’t anticipated it.

This generally applies to businesses. Businesses that thrive are businesses that weren’t supposed to exist, businesses nobody would have bet on.

This teaches us two things:

-> we are not capable to predict the future as we cannot predict Black Swans.
-> we are not aware of our inability to predict the future as we keep on trying to do so.

Experts who forecast have no idea about what they are doing.

It also means that we have more to gain from focusing on what we don’t know, than on what we know.

In some domains, like science and the stock market, the payoff to exposing yourself to Black Swans can be huge. In others, like the military, it can be deadly.

Another sign of our inability to deal with Black Swans is that we keep on learning from details, not the general. Eg: After WWI, the French built a wall to prevent Germany from invading again. The Germans just went around it.

-> we don’t learn that we don’t learn.

History often remembers heroes. But it never remembers silent heroes. Had someone passed a law that forces airlines to lock their cockpit doors on September 10th, 2001, 9/11 would have never happened, and no one would have known that this legislator was in fact, a hero.

Everyone knows prevention is better than treatment, but no one rewards prevention.

We glorify those that fix instead of glorifying those that prevent.

While we label “uncertain” as something we don’t know is uncertain (what time does Grandma come at tonight?), the author labels uncertainty as something he ignores that he ignores (in this case, ignoring that Grandma is even coming).

Platonicity is the author’s term to describe human’s tendency to focus on well-defined concepts instead of the abstract. It is what makes us think that we understand the world – while in fact, we don’t.

The main claim of the book is the following: the world is dominated by the unknown and highly improbable, while we only focus on the routine and on what we know.

-> one should begin with the study of extreme events to understand the world.

The second claim is that in spite of our increasing knowledge, the world will be more difficult to predict.


Part I: Umberto Eco’s Antilibrary, or How We Seek Validation

Books you read are less valuable than unread books because what you don’t know has more value than what you know.

The more you read, the more unread books you will have. Let’s call a collection of unread books antilibrary.

image 43
The antilibrary is the blue circle, the periphery, of what you have read, in yellow. As what you know (in yellow) grows, so does what you don’t know (the blue circle).

We tend to focus on what we know instead of doing the opposite. Eg: It’d be much more interesting to write what you didn’t study on your CV than what you did.

Let’s therefore name people that study the unknown antischolars.


Chapter 1: The Apprenticeship of an Empirical Skeptic

History and the Triplet of Opacity

History is a black box. It tells you what events happened, but not how they happened.

We have three problems when we look at history, called the Triplet of Opacity.

  1. The illusion of understanding: people that think they understand, but they don’t.
  2. The retrospective distortion: assessing matters after they happened.
  3. The curse of learning: the overvaluation of factual information.

Let’s first speak about the illusion of understanding.

When the Lebanese civil war started, everyone thought it’d last a few days, maybe weeks. It lasted 17 years. It’s the same thing for every war.

When studying similar events, we realize that history is a collection of sudden unpredictable events that each changed the course of history.

History doesn’t crawl. It jumps.

Dear Diary: On History Running Backward

Let’s now speak about the retrospective distortion. The author learned a lot by reading journalist Shirer’s Berlin Diary. The book is a daily account of what is happening in Germany from 1934 to 1941.

The journalist writes about the events as they are unfolding, in the present, not after they happened. As a result, the book gave an idea of how people felt at the time. And nobody thought war was about to break out.

Education in a Taxicab

Let’s now speak about the curse of learning.

Information isn’t always valuable. The Lebanese elite had a lot of information about the war with which they thought they could predict what would happen – they couldn’t.

Meanwhile, the common people like cab drivers had access to the same information (details about the war) but were aware of their incompetence in predicting the outcome of the war. As a result, they didn’t try.

Clusters

Clustering means grouping people per criterion. It’s not ideal as it reduces complexity.

200 years ago, Muslims were protectors of Jews, and both hated Christians. Today, it’s the opposite.

Things always seem to go well together, until they split.

This is the Black Swan generator. Clustering prevents you from seeing the true complexity out of which Black Swans appear.

-> no one knows what is happening, including tech execs at big companies.


Chapter 2: Yevgenia’s Black Swan

The author tells the story of the author Yevgenia Krasnova. Yevgenia wrote a book nobody would publish, so she published it on the Internet and was contacted by a small publishing house. The book grew in popularity and Yevgenia is now an established author.

Her success is a Black Swan.

NB: Yevgenia Krasnova is a fictional character invented by Taleb. She does not exist.


Chapter 3: The Speculator and the Prostitute

This is the most important chapter of the book.

There are two types of randomness:

  1. Randomness that welcomes Black Swan, called Extremistan, where things scale. Eg: wealth, wars, software, book sales, the stock market, etc. A trader is a scalable job. Buying one or one million shares is the exact same work. Movie acting is also scalable.
  2. Randomness that doesn’t welcome Black Swans (most of the time), called Mediocristan, where things don’t scale: dentistry, being a massage therapist, etc. They work by the hour, and can’t physically do more than x.

Eg: The story of Yevgenia happens in Extremistan.

Beware the Scalable

Scalable jobs enable you to make much more money, but you should avoid them.

Why?

Because scalable jobs only work if you are successful.

There are two types of jobs: non-scalable, driven by the mediocre; and scalable, where you have Giants and Dwarves.

The Advent of Scalability

When a job scales, it means that the best will get a disproportionate part of the pie.

When recording did not yet exist, opera singers worked in Mediocristan. If you wanted to listen to opera, you had to buy a ticket. When recordings were invented, everyone could listen to the best opera singer’s recording.

Average singers lost their job.

Travel Inside Mediocristan

In Mediocristan, where jobs don’t scale, it’s the opposite.

An extreme event is unlikely to change anything if the sample is big enough.

Eg: the average weight of 1000 random people won’t be any different if the heaviest person in the world is part of them or not. Weight doesn’t scale.

weight doesn't scale
Weight doesn’t scale.

The rule in Mediocristan, is this: When your sample is large, no single instance will significantly change the aggregate or the total.

The Strange Country of Extremistan

Now, get the average net worth of 1000 random people. Then take one person out and replace him with the richest person on the planet.

Does the average change?

Yes, it does – by a lot!

wealth scales
Wealth definitely scales.

Same thing with book sales, number of movies sold, academic references, etc.

The rule in Extremistan is inequalities are such that one single observation can disproportionately impact the aggregate, or the total.

Almost all social matters belong to Extremistan. Black Swans happen there too.

Extremistan and Knowledge

In Mediocristan, a usual variation from the mean won’t disturb the equilibrium. As a result, life is a peaceful and boring routine. You can trust the data, and the more data you have, the more you can predict the future.

In Extremistan, it’s not the case. A single unit can completely skew the data, which is why you can’t trust the data. Any attempt to predict the future will come very slowly.

Wild and Mild

Things you find in Mediocristan: height, weight, calorie consumption, car accidents, mortality rates.

Things you find in Extremistan: wealth, income, book sales per author, sizes of planets, sizes of companies, stock ownership, commodity prices, inflation rates, economic data.

The Extremistan list is much longer than that of Mediocristan.

The Tyranny of the Accident

In Mediocristan, the collective, the obvious, and the predicted rule. You will never lose a lot of weight in one day. You need a collective effect of days to do it.

In Extremistan, it is the individual, the unseen, and the unpredicted that rule. You can make a lot of money in a single trade in the stock market.

Extremistan does not de facto means you’ll have Black Swan, and Mediocristan will not de facto mean you won’t have any.

Don’t platonify it.


Chapter 4: One Thousand and One Days, or How Not to Be a Sucker

The Black Swan is expressed through the Problem of Induction: how can we logically make general conclusions out of specific instances?

Eg: a turkey is fed every day, therefore, the turkey believes it will be fed every day for the rest of its life…until an expected event happens at Christmas.

It works for one thousand days, until…it doesn’t anymore, and we find out that we knew was false, irrelevant, misleading.

what happens when you predict the future based on the past
The turkey was fed for 1000 days and eaten on the 1001st day. That day was a Black Swan.

A Black Swan Is Relative to Knowledge

Christmas is a turkey’s Black Swan. But it’s not for the butcher.

-> a Black Swan is a matter of perspective.

You can eliminate it with science, or by keeping an open mind – by “expecting” it.

Some Black Swans are sudden (a crash), some take years in their making (the ubiquity of computers in our lives.)

However, they should be perceived on a relative timescale.

Eg: 9/11 took a few hours, but changed the world forever.

Positive Black Swans are often slow, while negative Black Swans are often sudden. That’s because destroying goes quicker than building.

Sextus Empiricus was one of the first to talk about the Black Swan. He was born in 160, in Alexandria.

I Don’t Want to be a Turkey

Knowing about Black Swan should not scare you to take any risks. It should simply encourage you to consider what you had not considered before, so the Black Swan can be “preventable” somehow.

The following are consequences of our blindness to Black Swans:

  1. The error of confirmation: we make rules based on what we see and apply these rules to what we don’t see.
  2. The narrative fallacy: we tell stories that help us make sense of events, but that don’t explain anything.
  3. We behave as if the Black Swan did not exist.
  4. The distortion of silent evidence: what we see isn’t necessarily all that there is.
  5. We “tunnel” by focusing on a restrictive list of Black Swans.

Each of these ideas will be the object of each of the next five chapters.


Chapter 5: Confirmation Shmonfirmation!

People mix absence of evidence and evidence of absence.

Absence of evidence is saying that there is no evidence that something happened. Eg: I traded the stock market today and there was no crash. There is no evidence that a Black Swan happened.

Evidence of absence is saying that we have proof that a Black Swan will never happen because we are dealing with matters in Mediocritsan. Eg: a human being taller than 3 meters will never happen.

The reason people confuse these is that we cannot transfer knowledge and experience we use in a certain context to another.

In a psychological experiment, many statisticians failed at statistics questions phrased differently!

Evidence

When we believe something, we have a tendency to look for proof of it in our past – disregarding proof of the opposite.

This is the confirmation bias.

However, it is a fallacy. In the case of positive statements, a series of corroborative facts does not make it true!

Eg: the people I met today were nice, therefore, everyone is nice on the planet.

This works though, for negative statements.

Eg: I saw a black swan today, therefore, not all swans are white.

-> we get closer to the truth with negative instances than with positive ones!

This asymmetry is practical.

-> we don’t have to be 100% skeptical, just 50% skeptical (we have to be skeptical of positive instances).

In life, you only need to be interested in negative instances.

Observing 1 million white swans is a lot of data yet not sufficient to prove all swans are white.

-> data is great, but not in all cases!

One black swan though, is sufficient to say that not all swans are white. And then you can be 100% sure of this statement.

Karl Popper studied decision-making in situations where you don’t have all the information.

Popper’s idea is based on the open society, where doubt is constant. The society is built on “what is not true” rather than “what is true”.

For Popper a statement can be of two nature:

  1. Wrong.
  2. Not wrong yet.

Science advances by saying what X isn’t instead of what X is (according to him, we’ll never know what X is).

The problem is that humans have a bias toward the opposite: the confirmation bias. We only seek evidence of what we think is true.

The best chess players (and investors like George Soros) look instead for evidence that they may be wrong.

Back to Mediocristan

The savanna in which we grew up was much less dominated by Black Swans than the modern world, hence our inability to deal with them.


Chapter 6: The Narrative Fallacy

On the Causes of my Rejection of Causes

The narrative fallacy depicts our inability to observe a succession of facts without making up a story about how they’re all related.

We do so because stories help us make more sense, and remember better.

Splitting Brains

Theorizing about events is what people do naturally. Not theorizing is unnatural.

When you inhibit or enhance different parts of the brain, people tend to theorize more or less. That means that there is a physical cause as to why we theorize. It is biological.

The other reason is that knowledge is costly to store and retrieve for the brain. As a result, we look for a pattern in information and subsequently store the pattern. It’s the brain’s way of compressing information.

And we leave out the Black Swans out of a need to simplify.

Unlike what is often thought, the memory isn’t static. It’s dynamic and changes every time you revisit it.

Since narratives help us see the past as more predictable and less random than it was, we use our memory to decrease the cost of mistakes: “If I had done this…or that…it would not have happened.”

Don’t fight this tendency. Embrace it. But instead of trying to make the event less likely to happen, make it bound to happen.

The narrative fallacy is what happens in journalism. Journalists link different stories and events that have nothing to do with each other simply to make it more comestible for the audience.

Doing so, they make the world more complicated than it actually is (the world is random).

The Sensational And The Black Swan

The way narratives are phrased influences how we estimate the odds.

In general, we overestimate the likelihood of some Black Swans, while we underestimate it for others.

Why?

Because there are two types of Black Swans:

  • The narrated Black Swans, those you hear about in the mainstream narrative. Eg: winning the lottery.
  • Those no one talks about since they escape models.

As a result, the first ones are overestimated, while the seconds are underestimated.

The Pull of the Sensational

We will always be more attracted to the story than to the statistics.

When an Italian toddler fell into a well, the worldwide media were on alert.

That story went to Lebanon, in the middle of a civil war where people were dying in the street.

“One death is a tragedy, a million is a statistic”. Stalin.

The Shortcut

Daniel Kahneman and Amos Tversky found out that our cognitive system worked with two systems:

System 1: it helps us make quick decisions using mental shortcuts and biases called heuristics.

System 2: the actual thinking, the one that is painful to do.

Most of our mistakes come from using System 1 since we are often not even aware we are using it.

System 1 mainly works with emotions.

How to Avert the Narrative Fallacy

Our misunderstanding of the Black Swan is mainly due to our using System 1.


Chapter 7: Living In The Antechamber Of Hope

It’s hard to work for a profession in Extremistan as any success will be a Black Swan. It is hard because the brain is hooked on regular results, and worries if there is none.

This is why researchers, writers, and artists lead painful lives compared to dentists and massage therapists.

Where the Relevant Is the Sensational

In a primitive environment, the relevant is sensational: getting food, building a house, etc.

In this world, we direct our attention towards the sensational – which isn’t always relevant.

Nonlinearities

Linear relationships are clear.

Nonlinear relationships aren’t.

a non-linear relationship
You are happy to drink water at the beginning, but don’t want to drink liters of it.

Non-linear relationships are everywhere. Linear relationships are rare.

Process Over Results

We favor the sensational and visible. It’s difficult to keep on doing something that seems to deliver nothing.

Those that say they enjoy the process over everything else do not tell the entire truth. Sure, you enjoy writing…but having some readers wouldn’t be bad, would it?

Those that take the risk to work in Extremistan don’t even make that much money. Venture capitalists make more than entrepreneurs, science does better than scientists, and publishers do better than authors.

Human Nature, Happiness, and Lumpy Rewards

Making 100k per year for ten years > making 1 million in one year after 9 years of nothing.

Your happiness does not depend on the intensity of a happy moment but on the number of happy moments.

Unfortunately, modern life (especially in Extremistan) does not really deliver that.

Similarly, it’s better to have all of your negative feelings get out at once, than a bit every day.

The Antechamber of Hope

The Black Swan was presented as something we do not expect that happens.

But for the people working in Extremistan, it might as well be the event that they are waiting for which does not happen: Eg: book success. If you are a writer, you are expecting a Black Swan.

This highlights how there are two types of people: those that fall victim to a Black Swan, and those that prepare their whole life for it.

In essence, people either bet that the Black Swan will happen, or that it never will.

If you engage in such work, find people that are in the same position as you are so it’s not too hard.