Summary of Antifragile, by Nassim Taleb

Short summary reading time: 3 min

Long summary reading time: 31 min

Book reading time: 10h59

Score: 9/10

Book published in: 2012

Main Idea

We can classify anything in three ways:

  • Fragile: becomes weaker with variation and randomness
  • Robust: resists variation and randomness
  • Antifragile: becomes stronger with variation and randomness


Antifragile is a book written by Nassim Taleb.

It is the fourth book of The Incerto, a series composed of:

The book discusses the notion of fragility and antifragility.

The author explains that this book enabled him to come back to the roots of his job – figuring out a way to profit from catastrophes, these famous Black Swans – and that it should be considered the magnum opus of his work.

I would certainly agree, since all of his ideas, namely, randomness, fragility, Black Swans, antifragility, asymmetry, the Lindy effect, and skin in the game end up in the book.

It’s not an easy book, but it is worth it.

It will teach you to stop predicting and focus on the robustness or antifragility of systems instead.

You will see that it’s much easier to predict the collapse of a fragile structure than it is to predict what will happen when. Furthermore, it will teach you that suffering is good as it ultimately makes you stronger.

Find below the long-form summary of Antifragile.

I did not write an executive summary as Taleb wrote it himself in the prologue of the book.

Finally, you can buy the book here.

9/10 (some parts were a bit too long, others were unnecessarily complicated).

NB: Please skim through The Black Swan or Fooled by Randomness before reading Antifragile, as Taleb directly builds on them.

Table of Content


Book I: The Antifragile: An Introduction

Book II: Modernity and the Denial of Antifragility

Book III: A Nonpredictive View of the World

Book IV: Optionality, Technology, and the Intelligence of Antifragility

Book V: The Nonlinear and the Nonlinear

Book VI: Via Negativa

Book VII: The Ethics of Fragility and Antifragility

Summary of Antifragile Written by Nassim Taleb


You don’t want to suffer from uncertainty. You want to use it so that it propels you and makes you stronger.

Becoming stronger from shocks is called antifragility. Things that have gotten stronger with time are all antifragile: culture, ideas, political systems….

The antifragile loves randomness, meaning it loves errors. It enables us to play with things we don’t understand, to build things (we are much better at building than we are at understanding.)

By understanding the properties of antifragility, we can build a guide to nonpredictive decision-making under uncertainty. It’s easier to estimate whether something is fragile than it is to predict what will kill it and when. Risk isn’t measurable. Antifragility or robustness, is.

Antifragility is the answer to the Black Swan problem. We will see how to go from fragility to antifragility.

The difference is simple. Antifragility has more upside than downside, and fragility has the opposite.

If randomness and volatility are making an antifragile system stronger, then calm, predictability, and routine make it weaker.

By suppressing randomness, we fragilize antifragile systems (culture, the economy, education, politics).

Eg: the human body dies if not put under stress.

This is the tragedy of modernity. Those that want to help us the most, weaken us the most (and inversely).

The biggest fragilizer of antifragile systems is the absence of skin in the game.

Some manage to get the upside of a situation by shifting risk and downside onto other people. They are often hidden under the complexity of systems.

In the past, leaders took risks and accepted the downside, which is why they were leaders. Today, it’s the opposite.

Those at the top (bureaucrats, bankers, Davos members, and academics) get the upside while shifting the risk onto those at the bottom.

No one with so little downside ever exercised so much power.

This is unfair. You should never get antifragility at the expense of someone else.

If you want to live happily in our society, you need to become antifragile so that in the event of a Black Swan, you can survive (and thrive).

This is important since our multi-complex globalized system has increased complexity and randomness, making Black Swans ever harder to predict.

Robust Is Not Robust Enough

Nature destroys what doesn’t work and aggressively replaces it with something else.

Being “robust”, therefore, isn’t good enough.

You don’t want to suffer from Black Swan events, but profit from them.

Logically, the things that dominate the world today are antifragile.

Since it’s not possible to predict risk, we will focus on fragility.

For the same reason, we do not want to interfere with things we don’t understand, like society.

Unfortunately, society is built by people who do the exact opposite: the fragilistas.

As a result, society ends up being a complex system where you need to engage in things for which the benefits are small and visible and the downside, potentially big and invisible.

  • The medical fragilista who gives you medicine while your body is capable to regenerate.
  • The policy fragilista who tries to micro-manage the economy and blows it up.
  • The psychiatric fragilista who medicates children with too much energy.

We didn’t get where we are today thanks to them.

Where Simple Is More Sophisticated

A complex system doesn’t have to be complicated.

An intervention often leads to more problems than solutions.

Less is more, and often more effective.

Ethics have been replaced by law in modern society, but law can be bent with a good lawyer. The book is therefore about ethics.

First thing: if you see a fraud and don’t say it, you are a fraud yourself.

You can’t be nice to the arrogant nor arrogant to the nice.


Things can be categorized in three different ways, thanks to the Triad: Fragile, Robust, Antifragile.

Fragile VS robust VS antifragile.
Fragile VS robust VS antifragile.

Always think in which category the things you are reading about here are.

Eg: Not making any mistakes is fragile, on the left, and loving to make mistakes is on the right, antifragile.

In our case, fragile and antifragile are relative terms, they’re not absolute. Your body is antifragile up to a certain point.

Book I: The Antifragile: An Introduction

Chapter 1: Between Damocles and Hydra

Something antifragile gets stronger with disorder. It is the opposite of fragile.

Antifragile VS fragile
Antifragile VS fragile

Antifragility exists in many domains. The human body, for example, fortifies when it is deprived of food. By the same token, we can assume that it weakens when it is overly fed.

-> small doses of something “bad” can have a good effect.

This principle, (the antifragility principle) not only exists in medicine, but everywhere else. Unfortunately, humans are domain dependent: they only recognize principles in their own domains (eg: medicine) and can’t apply them to others (eg: economics).

Chapter 2: Overcompensation and Overreaction Everywhere

Antifragility can be somewhat compared to post-traumatic growth, the opposite of post-traumatic disorder.

This is how innovations work.

  1. Have a (serious) problem
  2. Find a solution

-> the energy released due to a setback creates the innovation.

This principle also exists in reverse. Not enough problems create danger by making us weak.

Eg: autopilot makes the plane “safer”, hence the pilots pay less attention, hence it increases the number of accidents.

Stressors, by stressing out, trigger a reaction to strengthen the body which overcompensates by getting stronger than it needs to respond to the stressors.

This principle is called overcompensation, and it is present everywhere.

Eg: If you train at the gym, your muscles will create a little bit more muscles than you need to lift. The body overcompensates.

The phenomenon of overcompensation.

Overcompensation is a form of redundancy. Redundancy is everywhere in nature. You have two kidneys and two lungs, two eyes, two ears, two arms, etc. Nature likes to reinsure itself. Redundancy is some sort of buffer in case something bad happens.

This is why innovation happens. Nature creates more energy than you need to get out of the situation -> hence innovation. Nature anticipates.

Innovation, in green.

The author subsequently explained he got a gym trainer that only focused on lifting more than he did the previous time, and that it worked fantastically great for him.

Overcompensation also means that the more barriers you put in the legs of your opponent, the stronger your opponent will become.

This is why riots are antifragile. The more violent the police is, the more violent the riot will be.

Information is also antifragile. The less you want people to know, the more they will want to.

Fire Feeds on Obstacles.

Conclusion: those whom we have benefitted the most aren’t those who helped us, but those who harmed us.

Chapter 3: The Cat and the Washing Machine

Everything that lives is antifragile to a certain point. Everything that is inert, isn’t since it breaks at some point.

In the case of living things, failure to self-repair comes from maladjustment – too few stressors, or not enough time for recovery.

Maladujstement, when you think about it, is a mismatch between the nature of the living thing, and the randomness of the environment.

Things created by humans (the economy, tech, businesses) are also antifragile, but are widely considered fragile because we don’t understand well how they work, because they’re complex.

Complex systems are systems with interdependencies, where the withdrawal of a unit creates a series of consequences beyond the unit. A noncomplex system is a system where any change is predictable.

Complicated noncomplex VS complicated complex

Complex isn’t complicated. A computer may be “complicated”, but it’s not complex.

When we deprive these complex systems of stressors, they become fragile. Bones, for example, become fragile when not used, which speeds up aging.

Stressors make antifragile systems stronger. Unfortunately, society is moving towards more and more comfort, which means that ironically, it’s becoming more and more fragile.

This process is called touristification. It’s taking the randomness and risk out of a process to make it a well-oiled predictable machine. Think of it as the electronic calendar: everything is scheduled, no space for surprises.

Humans don’t like that. We’re wired for randomness. Constant planning is not made for us.

In fact, our body is made to expand a huge volume of energy in a short period, then rest.

Consider running for your life chased by a tiger VS running on the treadmill.

Today’s stress is no longer “run then rest”. It’s “mild but constant”.

Today’s effort VS before.

Chapter 4: What Kills Me Makes Others Stronger

In a system, the sacrifice of some units is often necessary for the well-being of the whole.

It’s the fact that restaurants are fragile, compete with each other, and go bankrupt that makes the whole restaurant network resilient. If each restaurant was robust, the whole network would be weak – and the food would be disgusting.

This is why we need to die. We pass on genes slightly different to our kids that make the whole human race antifragile.

Similarly, when entire species die, it leaves space for other species much better suited to thrive in the new environment. It’s evolution working. Extinction is part of the game and helps the entire system.

Errors make antifragile systems stronger by purging the fragile from the system.

This principle is shown by the impact that errors have. Errors make the antifragile stronger, but break the fragile.

-> fragile needs to be predictive.

The errors in antifragile systems are needed. When investigating with trial and error, every mistake is finding a way that doesn’t work, hence bringing you closer to the solution.

The error is registered by the system. The sacrifice of the unit made the system stronger.

Eg: The Titanic. Had the Titanic not sunk, we would have kept on building bigger boats, and the catastrophe then would have been even more dramatic. The Titanic saved other, bigger boats, from sinking.

By sinking, the Titanic helped avoid another, bigger catastrophe.

Likewise, every plane crash brings us closer to perfect safety. The plane system is antifragile. Other planes don’t crash when one crashes.

The banking system however, is fragile. More banks are likelier to crash if one crashes too.

-> the banking system should be like the plane network.

As we said, the sacrifice of units makes the system stronger.

In an antifragile system like the economy, where units (companies) don’t want to die, these units prevent the system from getting stronger. There is therefore conflict.

In the past, the sacrifice of the weakest units to strengthen the system was perfectly accepted.

There is even an emotional switch in us that leads us to voluntarily sacrifice for the sake of the group.

The end of this idea only happened after the Enlightenment, where the individual prevailed over the group.

This is why we should celebrate entrepreneurs. They take the risk to fail and be destroyed so that the entire society can benefit from their success…or mistakes!

Book 2: Modernity and the Denial of Antifragility

Denying the units in the system of their fragility eventually weakens the system.

Strong system with natural variations VS weak system with stifled variation

Book 2 will explain how, by preventing volatility in antifragile systems, we increase the likelihood of Black Swans.

Chapter 5: The Souk and the Office Building

Imagine two brothers in London. One works for a bank, the other is a cab driver. The cab driver job seems riskier because there is more volatility in income.

But it is in fact safer. The cab driver can’t get fired, and won’t struggle to find a job passed 50 years old. Since he is in direct contact with the environment, he gets direct information about it and can react accordingly.

Eg: if his income decreases for a week, he should drive to another part of town.

Every small mistake the driver makes enables him to get better.

Unfortunately, humans hate small mistakes -> this decreases the antifragility of the system -> makes room for larger mistakes.

The banker, while earning a stable salary, can the next day lose his entire income. The cab driver job is therefore, safer.

Self-employed cab driver VS employed banker.

Let’s have a look at how it applies to political systems.

Switzerland, unlike most other countries, does not have a big central government. Its political system is bottom-up. The country is organized as a collection of municipalities that fight each other, assembled into a federation.

As a result, big variations can’t happen.

Rather, variations are small and bottom-up. They take the form of petty fights between neighbors.

This relationship that units have within the system is not scalable. Should municipalities increase the number of people, they will become big cities and the fights will become different.

Switzerland works well because humans behave better in smaller rather than bigger units.

While a big administration is shielded from its mistakes, Swiss politicians would have to face the regard of their neighbors and colleagues should they make big mistakes, like invading Vietnam.

This doesn’t happen when the space between the common people and the politicians is large, like in big countries.

Switzerland VS almost any other big country

On a small scale, people are human beings. On a large scale, people are large numbers.

-> Stalin could not have existed in a municipality.

Humans can’t grasp the abstract. A baby crying is traumatizing. 10 000 people dead is a statistic.

This is why bureaucracies don’t work. They are directed by civil servants that make decisions based on abstract numbers. Big is bad. Small countries don’t have lobbyists. Small companies either.

Switzerland knows variations alike to Mediocristan: small but frequent which cancel each other in the aggregate.

The opposite is Extremistan: stable systems that know few but catastrophic events once in a while.

There are therefore two types of variations: one where little but frequent variations maintain stability in the long run, and one where no variation maintains stability in the short term, but sees devastating events once in a while.

Two types of variation.
Two types of variation.

Chapter 6: Tell Them I love (Some) Randomness

The point we have been making is that it’s better to have a loose system with moderate variations than a stifled stable system with Black Swans.

The proof that tight control over systems led to blowups was made by James Clerk Maxwell, showing that tightly controlling the speed of engines led to instability.

This principle is everywhere.

In the market, fixed prices and the elimination of speculators lead to short-term stability but long-term fragility. If a currency never varies, the slightest variation will lead people to panic. Moderate variations reinforce stability.

Variations also act as purges. Small forest fires burn the most inflammable material, hence preventing bigger fires. Preventing all fires make forests much more subject to fires in the long run.

The same goes for companies. Stability and profits make them weak.

-> preventing randomness in an antifragile system weakens the system.

Let’s now look at how adding randomness can make an antifragile stronger.

  • Adding a bit of noise in a silent room helps people focus.
  • If a donkey is thirsty and hungry and at an equal distance of food and water, it will die, not being able to decide which one to go first. Randomness fixes this.
  • Political systems with random politicians work better.

If small fires prevent big fires, could small wars prevent big wars?

It may. Likewise, forced peace (like after WWI) can degenerate into…world wars.

-> since randomness is information, stable systems don’t exhibit visible risks.

Modernity systematically extracts randomness, leading to big instability.

The Enlightenment led man to believe that he was rational and that he could understand society (he cannot). This led to seeking optimization everywhere.

We went from a random environment like the jungle, to a stifled environment with streets, the 5-day workweek, financial planning, etc. Violence was transferred from individuals to the state -> denying of antifragility.

Modernity starts with the monopoly on violence from the state, and ends with their monopoly on fiscal irresponsibility.

Chapter 7: Naive Intervention

Naive interventionism is the urge to fix something that doesn’t need fixing.

-> medical interventions kill three to ten times more people than car accidents (in the US).

Treating someone for something they don’t have arises out of the agency problem. The agency problem happens when one party (the agent) has interests diverging from the one using his services (the principal).

The agency problem.

Unintended harmful consequences of an intervention whose purpose is to have a positive effect are called iatrogenics (eg: a medical treatment that causes more harm than benefits).

Going further, what could be the opposite of iatrogenics, that is, causing unintended positive side effects while trying to harm? There are no words for such practice.

For now, consider that such an attack would strengthen an antifragile system.

Eg: hackers attacking systems make the system stronger.

In a way, capitalism follows the same principle.

Can A Whale Fly Like an Eagle?

Economists and social scientists don’t understand iatrogenics.

Theories are fragile. A minor variation can discredit them. Phenomenology (the repeated observance of the same phenomenon without understanding its cause) is robust.

While iatrogenics in medicine are in Mediocristan, iatrogenics in economics and social sciences are in Extremistan, because of the concentration of power at the top of the state.

Gordon Brown and Alan Greenspan, by trying to eliminate economic cycles, considerably weakened the system.

-> it’s often better to do nothing than to do something, but not always.

Naive intervention should not be confounded with “no intervention at all”.

So, what should we control? Easy. We must limit:

  • Size
  • Concentration
  • Speed

These always increase both Black Swans’ risk and impact.

Intervention is not about being pro or anti. It’s about knowing when to intervene, and when not to.

The problem is that people get paid for what they do, not for what they don’t do.

The surgeon which gives you a chance to heal by yourself won’t be rewarded. Silent heroes exist, but they’re hard to find. True heroes are those who avoid a catastrophe, not those who fix it.

-> The Romans liked generals that did not go into battle.

Lao Tzu coined the term “passive achievement”, and the Latin words festina lente means “make haste slowly”.

Procrastination, as such, is a natural defense of our soul fighting against the reflex of interventions.

It’s a message from our natural willpower. If a lion runs after you, you won’t procrastinate. As a result, the cure to procrastination is changing what you do to do something you won’t procrastinate for.

A Legal Way to Kill People

The problem today is the overabundance of data. Not everything is interesting. It’s important to separate noise (what we can ignore) from information.

Eg: fasting deprives the body of information carried by hormones released when we eat. It also makes the body stronger.

-> data is toxic in large quantities.

The more data you get, the more you get drowned in noise, the less you know what’s going on.

Data is toxic.

The State Can Help When Incompetent

The Soviet State was so inefficient at food production that towns had to rely on producing food by themselves. Likewise, the neighborhoods they built were so random too that people really acted as communities and helped each other there.

State incompetence adds randomness which strengthens the system.

Chapter 8: Prediction as a Child of Modernity

The problem with predictions is that they are often wrong, and that we can’t predict Black Swans.

Robust and antifragile don’t depend on predictions, because they are not threatened by them. Only the fragile does.

Furthermore, we can control fragility more than we think.

  1. Detecting (anti)fragility is easier, therefore, you should work to minimize the harm a Black Swan would cause.
  2. Make things more robust so that they resist forecasting errors.
  3. Things become more antifragile due to the main stressor: time.

-> you can be excused for failing to prevent a tsunami. You shouldn’t be for building something that doesn’t resist tsunamis.

Book III: A Nonpredictive View of the World

Chapter 9: Fat Tony and the Fragilistas

You can’t predict in general, but you can predict that those who rely on predictions are taking more risks (it’s a bias), will have some trouble, perhaps even go bust.

This is how Fat Tony made his money. He bet on the loss of people making predictions.

Why? Because those who predict are fragile to prediction errors.

Fat Tony’s way of working is simple. He looks for the fragile, makes a bet on its collapse, and collects the paycheck when it effectively collapses.

Chapter 10: Seneca’s Upside and Downside

Seneca solved the problem of antifragility with stoicism.

The mainstream idea of stoicism works as follows: the stoic is indifferent to fate.

When Zeno of Kition lost their fortune in a shipwreck, he declared himself free from any burden and could then focus on philosophy.

-> this is the exact definition of robustness.

Whether we have or lose, nothing changes. The stoic is indifferent to what happens.


The real idea of stoicism though is different: the stoic is antifragile from fate, not robust. He has no downside, and plenty of upsides.

The problem with success is that it brings asymmetry -> when you have success, you have a lot more to lose than to gain.

-> you become fragile.

Losing is more painful than winning. Possessions make us worried about downsides (losing them).

In order to decrease the weight of loss, Seneca would mentally imagine having nothing and begin his adventures as if he had lost it all: with just a blanket (and two slaves).

-> when you assume that the worst possible thing has happened, everything else is bonus.

The idea isn’t to suppress emotions, but to domesticate them.

To quote the author, a Stoic is someone who transforms fear into prudence, pain into information, mistakes into initiation, and desire into undertaking.

So, why did Seneca keep his wealth (he was extremely wealthy) if he considered it negatively?

Because he focused on limiting the harm that wealth could give him.

He did so by considering what he had was an expenditure. If an investment came back to him, it was a benefit. If it did not, it was given for free.

Seneca was a winner, whatever happened. Pure antifragility – and asymmetry.

Fragility implies more to lose than to gain, equals more downside than upside, equals (unfavorable) asymmetry.
Antifragility implies more to gain than to lose, equals more upside than downside, equals (favorable) asymmetry

We put this idea into practice with the barbell strategy.

Chapter 11: Never Marry the Rock Star

Here’s how you can become antifragile.

First, decrease the downside -> lower exposure to negative Black Swans.

Businessmen often do the opposite – and it’s wrong.

-> you can’t enjoy the upside if, at any moment, you are at risk of dying.

Survival first – profits, second.

This leads to the barbell strategy.

A barbell is a bar where the weight is at each of its ends, with nothing in the middle.

Concretely, it entails being extremely conservative and low risk on one end, and taking a series of small risks with big upside on the other.

The barbell strategy.

Another nice consequence of the barbell strategy is that it reduces the notion of downside risk.

Eg: if you put 90% of your money in the safest asset and 10% in highly risky assets -> you can’t lose more than 10% – but you can have fantastic returns.

If you put 100% in medium-risk assets, you may actually lose everything.

This is the equivalent of women that marry the stable accountant that limits downside risks and cheat with the rock star once in a while.

Evolutionary biologists explain how women seek security on one hand while the best genes on the other.

Since they can’t get both in one partner, they engage in some sort of barbell strategy.

Book IV: Optionality, Technology, and the Intelligence of Antifragility

Saint Thomas Aquinas, quoting an Arab commentator of what Aristotle said, wrote that people did not do anything, except when they had a goal to achieve through their actions.

This is false.

The truth is that people choose what they want to do. They have options. An option is what makes you antifragile as it allows you to change your plans and adapt.

NB: please have a look here at how options in trading work.

Chapter 12: Thales’ Sweet Grapes

Thales, a philosopher, made a bet that the olive harvest would be plenty by buying the option to use all of the olive press in the city.

When the harvest ended up being plenty, he released each of the press on his own terms, and made enough money for the rest of his life.

Aristote, upon seeing this, made the conclusion that Thales knew the harvest would be great. It was in fact, the opposite. Thales did not know, which is why he bought a right, not an obligation on the olive press.

Thales’ option was antifragile: Thales had more to gain than to lose, more upside than downside.

Illustration from the book. We can see the loss is limited, while the upside is big.

Options are radically antifragile, and the best option of all is freedom.


  • Someone invites you to a party without any obligation to come (or stay): nothing to lose, everything to gain.
  • Renting a place: you can stay as much as you like, leave when you like. No downside, only upsides.

Options don’t care about the average outcome, only the favorable ones (since the downside doesn’t count).

The luxury industry is antifragile, it does not rest on the average, but on the extreme – the extremely rich people.

In society, this is the people at the tail (the extremely smart, or the extremely active) that enable society to move forward. Societies that succeed are societies that encourage those people, not the average.

If you have options, you don’t need insights, data, or knowledge. You just need to avoid doing dumb things and seize opportunities when you see them, exercising the right option as time goes by.

The author calls this system (getting results without needing intelligence and information) “the philosopher’s stone”.

Nature understands well the concept of options. A French biologist estimated that about half of embryos are naturally aborted. Nature keeps what it wants, and eliminates the rest.

Big discoveries are made at the expanse of small errors.

Here’s the definition of an option:

Asymmetry + rationality = option

Rationality means keeping what’s good and getting rid of what’s bad.

The fragile has no option; the antifragile chooses what’s best.

Nature is antifragile because it does exactly that: it chooses what’s best.

If we look at the most profitable businesses, they also have optionality. Real estate has options over the bank, and technology is made out of tinkering (trial and error, small mistakes, then positive Black Swan).

Chapter 13: Lecturing Birds on How to Fly

The Mesoamericans invented the wheel, but it was used for toys for children. They didn’t use them for transportation of goods – they never thought about it.

Likewise, the Greeks invented the steam machine – but did not realize how they could apply its power.

-> inventions are created due to randomness.

We find new stuff out by randomly tinkering and trying out stuff.

-> implementations don’t come (necessarily) from inventions. They too, require luck.

The simpler and more obvious the discovery, the less equipped we are to figure it out by complicated methods.

Trial and error have one overriding value people fail to understand: it is not really random, rather, because of optionality, it requires some rationality.

You need to understand when your trial yielded results, and when it did not.

In mainstream thinking, technology comes from “academic theory”.

Research -> scientific knowledge -> technology -> practical applications -> economic growth.

This model applies to a few things like the atomic bomb.

In practice, it works the opposite.

Random tinkering -> heuristics -> practice and apprenticeship

The idea that theory leads to practice and not the other way around is called epiphenomena. And it’s wrong.

This is explored in many phenomenons, where we tend to make causal relationships between two phenomenons that in fact have nothing to do with each other.

To quote the author: authors don’t get ideas after they write books. They get ideas before!

We don’t notice these because we can’t grasp what’s simple. We love the sophisticated (recall the wheels in Mesoamerica).

Chapter 14: When Two Things Are Not the “Same Thing”

In Adu Dhabi, oil money imported schools and world universities from around the world in the hope to create economic growth.

However, this is mostly a mirage. Switzerland, a country with a low percentage of the population educated in universities, people create wealth because of skills and stressors.

Innovation, as we said, comes from difficulties.

Where is the difficulty in Abu Dhabi?

People more educated don’t create more wealth. There is no evidence of that…but of the opposite. Wealth leads to people being more educated.

Education, however, isn’t the sign of anything. An entrepreneur is asked to build, not to talk. As a result, entrepreneurs don’t need to be good talkers.

So, there are two types of knowledge. The narrative, theoretical applied to practice coming out of universities, and the practical, results-yielding knowledge coming from practitioners.

Knowledge that ends up giving results is knowledge vetted through time: the oldest ideas are the best ones. Grandmother knowledge > expert knowledge.

Chapter 15: History Written by the Losers

The author tells the story of an economist worried to teach traders a complicated theorem supposed to help them with options trading.

However, the economist had it backward.

Option traders began trading before the theorem was established.

Even though they may not understand how the economy worked, they could trade options the same way a child can ride a bike without knowing about the physics that make it move.

The economist believed the theorem came before practice. In reality, practice came before theorem.

We don’t put theories into practice. We create theories out of practice.

Romans, Greeks, French built monuments and cities based on rules and heuristics, not mathematics. The math we use today to build them came after these buildings had been built.

What does it have to do with antifragility?

Practice is antifragile because it has options. When you practice to reach a result, you tinker, try, and change until you reach the result.

A theory is fragile. It does not leave space for tinkering and becomes invalidated as soon as its strict application does not yield the promised results.

A good example of such is cooking. There is no theory about cooking – it’s entirely apprenticeship-based.

Technology and its development work the same way.

Nobody invented the computer and the internet with the idea to connect them together. Both of them were results of needs for tech improvement, and happened to connect together in a random way.

The same thing happened in medicine, where the search for x led to the discovery of y. These tend to happen in the realm of private research, not academia. Why? Because academics have an agenda.

If they discover y, they will disregard it as this is not x.

The Inverse Turkey Problem

For the antifragile, the unknown is likely to bring good news, but bad news for the fragile.

Eg: biotech companies make no profit. But when they do – they earn big. They are antifragile. The opposite is insurance companies. They make a lot of money most of the time, but one event can bankrupt them completely.

Let’s summarize:

  1. Look for optionality. Rank things based on that.
  2. Look for things that bring open-ended payoff (no limits).
  3. Don’t invest in ideas or plans, but in people that can tinker and try until they find what works.

Chapter 16: A Lesson In Disorder

There are two types of environment. The ludic, with its set of pre-determined rules, and the ecological, where rules are unknown, which is real life.

Seen this way, parents may be the biggest hindrance to children’s development, taking them away from real life into ludic environments, like soccer games, classrooms, etc.

We need randomness, mess, adventure, and uncertainty.

-> only the autodidacts are free.

Chapter 17: Fat Tony Debates Socrates

The idea of this chapter is that you do not need to define a word to understand what it is.

The author tells the story of a trader trading green lumber, not knowing what green lumbers were. That didn’t stop him from being a good trader.

There are two types of knowledge. The one you learn in textbooks, and the one, opaque, you learn through practice.

Socrates asked people to define the words they used, and, should they not be able to do so, told them they shouldn’t use them. Doing so, he confused people – and was put to death because of that. He infused fragility in society.

Not everything you know or use can or (has to) de facto be explained.

Socrates was all about knowledge. Fat Tony is all about results. Fat Tony focuses on the payoff of his actions, not on their nature.

The payoff, the consequence, is always the most important thing.

To quote the author.

Philosophers talk about truth and falsehood. People in life talk about payoff, exposure, and consequences (risks and rewards), hence fragility and antifragility. And sometimes philosophers and thinkers and those who study conflate Truth with risks and rewards.

True and false do not matter. Asymmetric payoffs – consequences – is what does.

If you look at your decisions, you will see you make them based on fragility, not on probability. There is almost always an asymmetric result.

Eg: people that board the plane are unlikely to be terrorists, but we are fragile to terrorist events, hence, we check everyone.

-> the Black Swan (the event) and how it impacts you are not the same things. You will not care about a Black Swan if it does not impact you -> you’re obsessed with the impact.

And yet in society, after a Black Swan happens, society chooses to reinforce its risk-assessing model, instead of creating an antifragile structure capable to handle the Black Swan.

To conclude Book IV, practice is what matters, and theory learned in academic institutions doesn’t.

Book V: The Nonlinear and the Nonlinear

Chapter 18: On the Difference Between a Large Stone and a Thousand Pebbles

The fragility of something is vulnerability to the volatility of the things that affect it.

Furthermore, the impact is non-linear.

Eg: being hit by two stones of 50g < being hit by one stone of 100g.

The relationship is non-linear.

Why is fragility non-linear?

Because if it wasn’t the case, jumping one centimeter would put as much damage on you as 1/10000 of the damage you’d receive jumping 100 meters.

So, we are wired to resist small events, but not extreme ones. There are many, many more small events than extreme ones too.

-> we are immune to cumulative effects of small events.

Jumping 100 times one centimeter ≠ jumping 1 meter.

For the fragile, the cumulative effect of small shocks is smaller than the single effect of an equivalent single large shock.

This is why it’s better to lift heavy weights at the gym a few times, than light weights a lot of times.

This also means that the bigger the Black Swan, the disproportionately large the event will be.

Non-linearities relationships are everywhere.

A bit of randomness does not have a big impact, but as soon as you have too much of it, the impact is largely non-linear, and big.

Similarly, small is much more antifragile than big due to squeezes.

A squeeze is when you have no choice but to do something right away.

Eg: if you own an elephant and water becomes 50% more expensive (squeeze), your water budget will be much bigger than if you owned a dog.

Likewise, if you have to purchase, say, 1 million pieces of bread, for 1 euro, and manage to have a 10% discount, you save €100k!

10% on one piece of bread is a mere €0.1.

Finally, ants, being small, can carry their weight hundreds of times.

Big animals absolutely cannot.

Projects and Predictions

Uncertainty in the context of a flight will extend the duration of the flight – not shorten it. When a “surprise” happens in the airline space, it’s rarely a good one.

The same can be said of projects.

More uncertainty will incur more costs, more delays.

Eg: WWI was supposed to last a few months. By the time it ended, UK and France were heavily indebted, and it had lasted…four years.

-> complexity + asymmetry = explosive errors!


Fragility in any domain, is non-linear.

Chapter 19: The Philosopher’s Stone and Its Inverse

In 2003, the author saw that Fannie Mae (a lending company) made very little money when an economic variable moved downward, and would lose a massive amount when it’d move upward.

-> it was the definition of fragility, and the author subsequently bet on its collapse, which happened in 2008.

-> measures of fragility are much better than measures of risks (which don’t work!)

Measuring fragility is easy. All you need is to check by how much the downside increases with variation.

Eg: if a city’s traffic slows down with 1000 cars by 10 min and by 30 min with 1000 more cars, you have something fragile.

So, we can classify things in three distinctions (coming back to the Triad: fragile, robust, antifragile):

  1. Things that like disturbances in the long run (evolution, scientific discovery, etc)
  2. Things that are neutral to disturbances (a book)
  3. Things that dislike disturbances (traffic)

Now, we talked about the philosopher’s stone.

The philosopher’s stone works as follows: if you have positive asymmetries and the option to realize them, you will do better in the long term in the presence of uncertainty.

The more role optionality plays, the more you will outperform.

Book VI: Via Negativa

Via Negativa means not designing something by what it is, but what it isn’t. Likewise, the secret to antifragility sometimes is more about stopping doing things or removing them, than doing them and adding them.

Eg: when Michelangelo was asked by the Pope looking at David the secret of his genius, he said he just “removed everything that wasn’t David”.

In practice, the ones at the top act more by avoiding, than doing.

  • Chess masters win by not losing
  • Rich become rich when they avoid losing money
  • Religions are about what you cannot do
  • Life is about what to avoid
  • Good political systems focus on removing the bad guy, not on getting the good ones in.
  • Focus is not about saying yes to one thing, but no to 1000 things.

Antifragility is reached by not being a sucker.

-> we know more about what is wrong than what is right.

Negative knowledge is more robust than positive knowledge.

-> knowledge grows by subtraction more than by addition.

What is wrong is robust, and what is unknown is fragile.

Another idea linked to via negativa is less-is-more.

Less-is-more is applicable in Black Swan’s domains – Extremistan – where they can have a disproportionate effect. If you focus on profiting from a Black Swan, all you need is to be right once.

In a way, less-is-more is tied to Pareto’s law, which is a power law. 20% of people own 80% of the land, 1% of authors sell 99% of the books, etc. Likewise, a 1% change in a system can lower fragility by 99%.


  • A few homeless people cost the state a lot of money
  • A few employees annoy everybody
  • The sickest 10% of the population are responsible for 64% of healthcare cost

If you have more than one reason to do something, don’t do it. It means you are likely trying to convince yourself to do that thing, which means, you actually don’t need to.

Likewise, people should be known for one idea, and one only.

-> avoid people with big resumes that wrote about everything.

Chapter 20: Time and Fragility

What is old is superior to what’s new, because what is old has resisted time, and time crushes what is fragile.

If something survives, it means it is not fragile.

Therefore, the way to imagine the future is to look at what is fragile now, and take it away.

The future is what’s left.

What futuristic authors like Jules Verne failed to predict was that our world is much closer to theirs than they imagined.

Think about it. Shoes, restaurants, and silverware exist for millennia.

Let’s now talk about the Lindy Effect.

To Age In Reverse: The Lindy Effect

The Lindy effect separates the perishable from the non-perishable.

Humans are perishable, DNA is not. A car is perishable, the automobile industry isn’t.

The Lindy effect works as follows:

For the perishable, every additional day in its life translates into a shorter additional life expectancy. For the nonperishable, every additional day may imply a longer life expectancy.

The longer something has been existing, the longer it is expected to exist.

Lindy things age in reverse because if something has been existing for a long time, it is robust, and the longer it lives, the more robust it gets!

In a way, the future is the past. By looking at what has lived the longest, we will know what will live the longest.

Chapter 21: Medicine, Convexity, and Opacity

Only take medicine when the payoff is largely more positive than the potential harm (eg: surgery).

When the payoff appears small, you expose yourself to consequences that may not yet appear.

Eg: smoking. It took decades to find out it was actually bad.

When something is not natural, it needs to prove first it’s not harmful, and that takes time.

First Principle Of Iatrogenics (Empiricism)

Evidence of harm is not what we are looking for when testing a new drug since this will likely come in the future. Rather, evidence of no harm is what we want.

Second Principle Of Iatrogenics (Nonlinearity In Response)

We shouldn’t take risks with healthy people, but we should with those deemed in danger as it’s worth it – if they’re going to die, might as well try everything.

If your tension is a bit too high, the chance to benefit from a medicine will be 5.6%.

But if blood pressure is high, then you benefit from 26% up to 72%.

Similarly, you’re unlikely to find drugs that will make you feel healthier than already-healthy as if it existed, nature would have already found it.

The problem with medicine is that its successes have always been shown, and its failures, hidden.

Furthermore, it always takes years, if not decades, for the side effects to show up – then to be diagnosed.

When it comes to something like blood pressure, normal medicine does not take into account the variabilities. It’s not because it’s a bit high once, that it is all the time!

As a result, we medicate people that don’t need medication, and kill them in the process.

Chapter 22: To Live Long, But Not Too Long

It is often advertised that we live longer now than before, but it’s not so sure.

Most people died at birth, giving birth, or in battles in the past. Those that lived, lived long.

Then, the solutions medicine brought need to be contrasted with modern plagues, such as smoking. In fact, it has been shown that not smoking would be the biggest improvement overall for the healthcare system (less is more).

Overall, strikes in hospitals did not let more people die, as only the very important surgeries were performed. It has been shown that people would live longer if the medical budget was cut, and where medicines would be administered only in the most extreme cases -> most medicines are administered uselessly.

The Lindy effect also works with food. If you want to make sure food is healthy, only eat what we have been eating for 1000 years.

Furthermore, the key to good nutrition may also be in eating at random times and not regularly as we do, and eating random stuff and not per diet like we do.

Herbivores eat regularly. Carnivores do not. Predators go for long periods without eating, then feast. And it’s never “balanced”.

As a result, you may be eating a lot of meat at some point, then a lot of vegetables at another, then fast.

Fasting has been shown to be excellent for health.

Finally, breakfast is not a natural thing – it may even be harmful. You’re not supposed to find food upon waking up, but should hunt to get it first.

-> go for a run in the morning.

Book VII: The Ethics of Fragility and Antifragility

Under opacity, some can hide risks and get away with them.

The only way to mitigate risks is through skin in the game.

Chapter 23: Skin in the Game: Antifragility and Optionality at the Expense of Others

In older societies, there still were heroes, people that decided to assume the downside for everybody else.

Today, it’s the opposite. Politicians get elected not to assume the downside, but to benefit from the upside.

This leads to another triad.

Those with no skin in the game that benefits from the upside; those with skin in the game that neither benefit nor suffer from anyone; and those that assume for other people – heroes and adventurers.

In the past, courage was dying in battle. Today, it is to stand for an idea, or for certain values.

Those that don’t want to take risks for their opinions or take on opinions that carry no risk, are not as honorable.


A lot of professions are becoming antifragile at the cost of our fragility: government employees, academic researchers, journalists.

Hammurabi’s code, now 3 800 years old, made sure to get everyone’s skin into the game.

Eg: if a house collapses and kills the owner, the builder will be put to death. If it kills the son of the owner, the son of the builder will be put to death.

-> The Romans asked the engineers to stand under the bridge they built. Ethically, someone voting for war should be at the front in the battle.

Same goes for predictions. Predictions originating from someone with no skin in the game aren’t worth much.

The problem is that in our modern world, intellectuals with a lot of power make recommendations without skin in the game. They have privileges, and no obligations.

Karl Popper thought ideas competed and that the least wrong of them would survive. But it’s wrong. It’s the people/societies with the right set of ideas that survive. The others die.

Chapter 24: Fitting Ethics to a Profession

Someone who lives with 2k per month without being dependent on anyone is more free than someone who spends 1 million a year being dependent on his job.

A lot of people, as they earn more, spend more. As a result, they are never free.

The Tyranny of the Collective

Academics with unusual ideas won’t get jobs because they don’t have the ideas that everybody has.

So everyone is teaching and learning stuff that everyone knows is wrong. No one has enough freedom to break the cycle.

Chapter 25: Conclusion

Everything gains or loses from volatility. Fragility is what loses from volatility and uncertainty.

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  • Post category:Summaries
  • Post last modified:May 26, 2022