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Book Summary – The Black Swan : The Impact of the Highly Improbable

The Black Swan - Book summary

The Black Swan is the 2nd book in the five-book series by Nassim Nicholas Taleb on uncertainty. In this book, he explains the phenomenon of Black Swans, i.e. extremely unpredictable events that have a massive impact on our societies and the course of history. In this free version of The Black Swan summary, we’ll outline some of the key ideas in the book, including how we’re surrounded by randomness beyond our control, why we struggle to accept it, and how we can address our blind spots.

The Black Swan: An Overview

What are Black Swans and why are they important?

For thousands of years, it was widely believed that all swans were white. Then in 1697, a Dutch explorer Willem de Vlamingh discovered black swans in Australia, debunking this universal “truth” overnight. The term “Black Swan” has since been used to describe the occurrence of a seemingly-impossible event.

3 key features of Black Swans

Taleb identifies 3 key features of Black Swans:

  • Rarity: Black Swans are outliers that can’t be reasonably expected to happen based on past events.
  • They have a profound impact on our society/world.
  • Retrospective predictability: Although the events are unpredictable, humans tend to explain them on hindsight as if they could be perfectly understood and predicted.

Black Swans are not inconsequential anomalies, but a significant phenomenon that shapes the very world we live in. Many historical events that drastically impacted our societies and lives were actually Black Swan events. These include the 2 world wars, the fall of the Berlin Wall, the 11 Sep 2001 terrorist attacks, the rise of the Internet, the 1987 stock-market crash, the 2008 financial crisis and the 2019 Covid pandemic. In all of these cases, no one could’ve predicted the events in advance (no matter what we claim afterward), nor could we have foreseen their sweeping effects.

Many of the major turning points in your personal life (e.g. how you met your spouse, your biggest gains and losses) were also likely to have been unexpected, i.e. they didn’t come from standard events on your daily schedule.

The Black Swan summary_Why Black Swans are important

2 Types of Uncertainty: Extremistan vs. Mediocristan

Differences between Extremistan vs. Mediocristan

Nassim Nicholas Taleb differentiates between 2 types of uncertainties:

  • In Mediocristan environments, there’s a limit to the amount of randomness or deviation from the average. Inequalities exist, but they’re mild or controlled. Usually, there’re some physical constraints (e.g. height, weight, running speed) which limit the amount of variability. For example, if you add the tallest or heaviest man in history to a sample size of 1,000 people, the outlier won’t make a real difference to the average. There’s also typically a linear relationship between variables. Prediction is possible in such environments or systems.
  • In Extremistan environments, there can be wild randomness and extreme deviations. Typically, there’re no physical constraints and no known upper/lower limits (e.g. knowledge, financial markets, e-book sales, social media “likes”). Thus, the outliers can make a big difference—if you add the net worth of Jeff Bezos or Bill Gates to a group of 1,000 people, it will drastically shift the average.


A key difference between Mediocristan and Extremistan is the scalability. Something is scalable if it can grow exponentially with little/no additional resources. A massage therapist is a non-scalable profession since he/she can only serve so many clients in a day. However, a singer in the digital age is a scalable profession since he/she can perform a song once, record and disseminate it widely. Scalability can create vast inequalities, extremities and winner-takes-all situations. Top singers earn vastly more than average singers, even though they aren’t proportionately more talented.

Black Swans are so disruptive partially because they often appear in scalable Extremistan scenarios. A single unexpected event can flip everything on its head with potentially infinite impact. You can’t lose much weight in 1 day (Mediocristan), but you can lose all your money in an instant (Extremistan).

Overcoming our Blindness to Black Swans

Black Swans are the “unknown unknowns” which can’t be accounted for, even by the most sophisticated models. Yet, we tend to pretend that Black Swans don’t exist. We focus on what little we can see/grasp, deluding ourselves that we know exactly what’s happening. In reality, what we know is just a miniscule fraction of the vast amount of things that we don’t know.

Here’s a brief overview of why our world is inherently unpredictable and why our human mental biases lead us to be over-confident of our predictions and conclusions. Do get a copy of the complete version of  The Black Swan summary for more details.

The Black Swan summary_Why we're blind to black swans

Human Biases and Tunneling

In the book, Nassim Nicholas Taleb explains why the human brain is so susceptible to misconceptions and overconfidence, and what we can do about it.  In our complete 15-page summary, you can get more details and examples on:

  • The confirmation bias and the round-trip fallacy, including how we confuse an absence of evidence with an evidence of absence, and the difference between negative empiricism vs naive empiricism.
  • What’s the narrative fallacy and how to overcome it
  • Why we’re blind to nonlinearities and the implications
  • Why empirical evidence is flawed due to silent evidence and why we’re prone to the survivor bias

Difficulties of Prediction

Ultimately, our world and future are unknowable and unpredictable because of various factors, including:

  • The role of chance and luck in inventions and game-changing discoveries
  • The inherently unpredictable nature of dynamical systems and variables that behave in inconsistent or nonlinear ways
  • We can’t make accurate predictions with flawed and incomplete information.

Do check out the full version of The Black Swan summary for to zoom in on each of these factors.

The Scandal of Prediction and Epistemic Arrogance

The combination of the 2 sets of factors above means that: humans are terrible at prediction, yet we keep making predictions without realizing how frequently we’re off the mark. Taleb calls this the “scandal of prediction”.

In our full 15-page summary, we’ll explain:

  • What’s epistemic arrogance and its implications;
  • Why we should beware of experts’ predictions (and our own predictions);
  • Why the past is even harder to predict than the future; and
  • How to stop being suckers and start becoming smarter about the way we see the world.

Coping in a World of Uncertainty

If we’re surrounded by randomness and cannot plan ahead with certainty, is there anything we can do?  In our complete version of The Black Swan summary, we’ll explain how you can leverage the inherent asymmetry of Extremistan environments to maximize your upsides for positive Black Swans while minimizing the downsides for negative Black Swans.

Getting the Most from The Black Swan

In this article, we’ve briefly outlined some of the key insights and strategies you can use to achieve desired change. For more examples, details, and actionable tips to apply these strategies, do get our complete book summary bundle which includes an infographic, 15-page text summary, and a 26-minute audio summary.The Black Swan summary - book summary bundle

In this book, Nassim Nicholas Taleb uses numerous examples and research studies to explain the Black Swan phenomenon and the fallacy of human predictions. Besides the key ideas captured in our summary, the book also includes detailed comparisons between Mediocristan and Extremistan environments, with several additional chapters to discuss the technicalities of concepts such as bell-curves, deviations, inequalities, randomness, fractality etc. You can purchase the book here for the full details, or check out

[To learn more about ethics and asymmetry in an uncertain world, do check out our Skin in the Game summary!]


About the Author of The Black Swan

The Black Swan : The Impact of the Highly Improbable is written by Nassim Nicholas Taleb–a Lebanese-American writer, scholar and mathematical statistician, best known for his work on randomness, probability, and uncertainty. He received his bachelor and master of science degrees from the University of Paris. He holds an MBA from the Wharton School at the University of Pennsylvania, and a PhD in Management Science from the University of Paris. Taleb was a former option trader and risk analyst at various trading and financial firms. He has been a professor at several universities, and has been co-editor-in-chief of the academic journal Risk and Decision Analysis since September 2014. He has also been a practitioner of mathematical finance, a hedge fund manager, and a derivatives trader, and is currently listed as a scientific adviser at Universa Investments.

The Black Swan Quotes

“What we see is not necessarily all that is there.”

“We see the obvious and visible consequences, not the invisible and less obvious ones. Yet those unseen consequences… generally are…more meaningful.”

“Governments are great at telling you what they did, but not what they did not do.”

“Our ideas are sticky: once we produce a theory, we are not likely to change our minds.”

“We attribute our successes to our skills, and our failures to external events outside our control.”

“We have a natural tendency to listen to the expert, even in fields where there may be no experts.”

“If you believe in free will you can’t truly believe in social science and economic projection. You cannot predict how people will act.”

Click here to download The Black Swan summary & infographic

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