Seems like a good week, with the Coronavirus pandemic and all, to talk about this:

Upon request, I feel like I ought to explain some of these misunderstandings. I already wrote one a few months back on misunderstanding “skin in the game” (it’s not an incentive; it’s a filter). This week we’ll tackle another one: antifragility. 

Antifragility = you need disorder

First, what antifragile isn’t: antifragile does NOT mean “not fragile.” It is not robustness, durability, or ability to withstand adversity. I hear some people use antifragile to mean “immunity”, or “super-resilience”, which aren’t it. Other people equate antifragility with optionality, which is closer, but still not quite it. (More on that later.)

Antifragile means “negative fragility”. This can be tricky to conceptualize, since there isn’t really a word for it in English, or in any language as far as Taleb has ever heard of. Nor are there convenient visual or object analogs we can easily imagine, like the opposite of a porcelain vase or some other clearly fragile object. We can picture something fragile, and then picture the absence of that fragility. 

But what about the other side of that spectrum – negative fragility? If fragility means “suffering from disorder”, what about something that gains from disorder? 

Here, we find antifragility: things that need disorder in order to thrive, and will actively suffer if left at rest. Most objects in the world don’t have this property, but a lot of complex systems and living things do. Markets, democracies, and immune systems are all antifragile: without variance, they stagnate and die. With variance, especially unexpected variance, they grow stronger. Disorder is a key ingredient to how they function. 

The opening example in chapter one, which is the most memorable thought experiment in the book, restates the idea well:

You are in the post office about to send a gift, a package full of champagne glasses, to a cousin in Central Siberia. As the package can be damaged during transportation, you would stamp “fragile”, “breakable”, or “handle with care” on it (in red). Now what is the exact opposite of such situation, the exact opposite of “fragile”?

Almost all people answer that the opposite of “fragile” is “robust,” “resilient,” “solid,” or something of the sort. But the resilient, robust (and company) are items that neither break nor improve, so you would not need to write anything on them – have you ever seen a package with “robust” in thick green letters stamped on it?

Logically, the exact opposite of a fragile parcel would be a package on which one has written “please mishandle” or “please handle carelessly.” Its contents would not just be unbreakable, but would benefit from shocks and a wide array of trauma. 

In antifragile systems, stressors are information

Most people get this far okay. But you can tell they sort of sputter out when they try to logic the core mechanism for how variance makes an antifragile system stronger over time, and what is different about those systems compared to fragile or robust ones. One shortcut to understanding it is to think about antifragility in terms of information theory

Think about a system, humming along in its normal state, and then a stressor is suddenly introduced. A wrench gets thrown into a machine; market demand for a product suddenly changes; a new threat reveals itself; customers start complaining to you in a way you hadn’t anticipated. How does this affect you?

In a fragile system, that stressor creates uncertainty. You had a plan, and you were good to follow that plan so long as you stayed within a certain state. But now you’re thrown into a new state, so your plan no longer works. You’re in trouble. That’s fragility.

In a robust system, that stressor is information-neutral. You had a plan, and there’s enough buffer or slack in your system to absorb the stressor. Your state is resilient to the new challenge; the plan continues.

In an antifragile system, that stressor resolves uncertainty. You had no preexisting plan; the stressor tells you what to do. In an antifragile system, stressors are information. Without stressors, an antifragile system is rudderless. It doesn’t know how to grow or what to do. It actively suffers, until a challenge gives it direction.

Antifragility and optionality aren’t the same thing

The rookie mistake is to confuse antifragility and robustness; the more advanced mistake is to confuse antifragility with optionality. They’re related, but they aren’t the same thing. Options are something you have, whereas antifragility is something you do

Optionality is a precondition to antifragility, but just because you have options doesn’t mean you’re antifragile. A fragile organization, facing an unknown stressor, may have plenty of “options” available to them. But if you don’t know what to do with those options, and if you don’t know how to grow into the challenge, then those options don’t do you any good. 

Antifragility is something you do, rather than something you have or something you are. Antifragility is an operating state of growing through continuous reaction. It’s like the opposite of predicting the future. You’re not making any forward-looking assumptions about anything, but you need disorder: you need a state change to have something to react to. Good antifragile systems react quickly and correctly, like the Hydra growing new heads when you cut one off. Without disorder, the Hydra doesn’t grow. 

Taleb’s favourite go-to example is deadlifting: free weights make you stronger (as opposed to exercise machines) because they expose you to more stressors, and more degrees of freedom in how they stress you. Your muscles and joints are antifragile, because of what they do: they are oriented towards those stressors, and they use those stressors as information. Optionality is not enough: having the option to grow is not the same as growing in active response to stress.

Accordingly, antifragile systems and organisms tend towards a common theme: bottoms-up decision-making, rather than top-down decision making. Antifragility requires real options, and real options are low-cost. Antifragility is only successful if you can actually detect, react, and grow in response to deviations from your present state in real time; the only way you can feasibly do this is for disorder detection and response to take place at a small enough resolution, and tight enough turnaround time. Top-down systems have a hard time with antifragility, because for them, all options are costly. 

The immune system: three lines of defence

In my opinion, the best example of an antifragile system that gains from disorder (and that’s probably on a lot of your minds right now) is your immune system.

What are we talking about when we say “The immune system?” First of all, you don’t have one immune system, so much as you have three layers of defence who work to protect you from pathogens and disease. They all work together, particularly the second and third layers who coordinate their work a lot. Still, we can still think of them as three distinct systems that have their own strengths and weaknesses. 

The first one is pretty easy to understand: it’s your skin. Your skin is a wall that keeps stuff out. It’s simple, but effective! It’s fragile, though. Your skin suffers when stressed. If you’ve ever had a cut that got infected, that’s what happened: the wall got breached, and you suffered the consequences. Nonetheless, it’s a good thing you have it. It’s a simple, cheap, and effective way to keep 99% of the pathogens and toxins you encounter in the world out of your body and away from where they can cause problems. 

What about threats that get through the wall? The next two layers of defence are more targeted and deliberate. In vertebrate animals like us, there are two levels to our immune response: innate immunity, which is a characteristically robust system, and adaptive immunity, which is antifragile. 

When you’re dealing with a threat, the immune system has to do two things: identify it, and destroy it. Destroying it, relatively speaking, is the easy part. Both the innate and adaptive immune system rely on similar weaponry to do so: we enlist specialized white blood cells and marker molecules to tag threats, break them apart, neutralize them, or just eat them. The harder part is knowing what to destroy: how does the body equip itself to know what a threat looks like, so that if it sees something, it can say something?

The innate immune system has learned what threats look like by an old, slow, but tried-and-true method: evolution. The innate immune system acquires its threat models through evolutionary selection from generation to generation, which is very slow in the context of our own lives (evolution typically takes thousands of generations to work) but still totally works as a way of identifying pathogens that have been around long before we were. 

White blood cells in the innate immune system all carry around an “most wanted list” of threat models in their DNA. Remember, your DNA is more or less fixed from birth: the set you get from your parents is the set you’ve got for life, and you benefit from the evolutionary experience of thousands of generations before you. It’s spread out among every white blood cell and every precursor cell of your body, and the response that it triggers gets carried out by dozens of different cell types and attack mechanisms, so it’s pretty resilient to shock and distress. 

But it only works if that threat can be identified in advance; and unfortunately “in advance” means in evolutionary terms: “before humans”. Fortunately, just as your skin is good at keeping out 99% of all bad stuff, the innate immune system is good at keeping out the next 99% of bad stuff – most pathogens that can hurt you have existed in the world for a very long time. But not all of them. So then what?

The adaptive immune system: stressors are information

In contrast to innate immunity, your adaptive immune system does not have the luxury of keeping a most wanted list handy. Your adaptive immune system has a harder job. It has to identify pathogens and bad stuff that you’ve never seen before, and possibly that no one has ever seen before. Bacteria and viruses evolve at a rate that’s orders of magnitude faster than us. We are perpetually playing catch-up in the fight against new viruses and new bacteria that have evolved into existence. 

It’s worth taking a minute to go through the biological mechanics of this challenge. The way that your white blood cells detect foreign intruders is by continually testing everything they encounter for certain identifying factors, called antigens. To do that, the cells need to express their own counterpart identifiers, called antibodies and antigen receptors, which selectively bind to a specific antigen partner. 

Antigen receptors, like most of the rest of the stuff in your body, are proteins; and the recipe for how to make them is in your DNA. Your innate immune system comes with its DNA recipes for antigen receptors pre-installed; you inherited them from your parents, who got it from their parents. Over time, you can evolve the right DNA recipes for catching the usual suspect pathogens. But how do you predictively design and generate antigen receptors, for threats you’ve never seen? 

The adaptive immune system does something pretty remarkable here: it generates them randomly. New white blood cells repeatedly scramble and rearrange the basic building blocks of these receptors in order to generate new combinations: up to 2.25 x 10^18 potential combinations in humans, at least so we believe so far (it could be higher). Instead of trying to predict the future, your adaptive immune system instead just makes a little bit of everything. 

The vast majority of these cells will never live out their intended purpose. They’ll float around, never finding that new theoretical virus for which they were randomly and specially generated. But every once in a while, one will find its target. (It doesn’t actually just run into it in the wild; that antigen gets “presented” by one of your innate immune system’s cells, who are actually a bit more clever than we’d given them credit for before. They may not know what they’re looking at, but they understand how to “hand over authority”, so to speak, to the adaptive system.) After going through a critical checklist to make sure you haven’t accidentally found part of yourself, the system gears up: it has its marching orders. 

So you’ve found a real threat, and it merits a real response. The first thing your immune system does is make massive numbers of copies of that lucky white blood cell; it also powers up its own fleet of weapons that it’ll use to eliminate the threat that it now knows how to identify. 

Then – and here’s the important part – once the threat is conquered, that threat is now stored permanently in our most wanted list, just like the classic threats that we automatically know how to neutralize. The next time we see that same threat, we’re ready. And we can get to work fighting it way faster; in fact so fast you never even feel sick. That’s what we mean when we say we’re immune to something, and it’s how vaccines work. 

Vaccines are a clever hack. By presenting the body with a small and disabled part of a disease, we can use society’s current knowledge of what diseases are currently dangerous (which works a lot faster than evolution does) to pre-load our adaptive immune system with its own most wanted list. That’s what you’re doing when you get your shots. 

In last week’s issue, one question that still seemed to trip people up a bit was the difference between optionality and antifragility. The adaptive immune system is a great illustration of the difference. The first part – pre-generating all of those randomly generated antibodies and antigen receptors – 1) is a kind of optionality, and 2) is a prerequisite for antifragility: you need to have all of these options available to you, so that you’re ready for anything. 

But it’s not enough. You also have to react. The second part – using stressors as information, reacting, and establishing permanent strength because of that reaction – that’s antifragility. Or, to be fair, that’s how I use the term antifragility. It may be narrower than other definitions, but I find it’s useful to be deliberate and specific with how you use words like this. 

Over the course of your life, your adaptive immune system grows stronger every time you’re exposed to new pathogens and diseases. Every time you give it a workout, it learns and strengthens. That’s why, unless you have an immune deficiency, it’s important to get a lot of exposure to dirt and germs early on when you’re young, and then continually throughout your life too. 

The biggest insight here, I think, is to really wrap your head around the nature of information in this system. The presence of a new, unknown pathogen resolves uncertainty for the adaptive immune system, because it tells it something explicit: Hey, you know how you randomly generated all of those antibodies and antigen receptors? This one is the right one. The stressor tells you what to do, and then makes you stronger in a deliberate, non-accidental way. 

Compare this to the innate immune system, which has no such capacity (the stressor simply goes unregistered until it’s too late) or barriers like the skin (the stressor actively makes it weaker). For the innate immune system, the stressor is not information: it does not resolve any uncertainty. Information isn’t what you’re told; it’s what you understand!


In context of what’s going on with the coronavirus pandemic, you can see this relationship between optionality and antifragility playing out in real time. You can compare different countries’ reactions and responses and see how, for example, what’s a cheaper option to Singapore might be an expensive option for America (swift state action to clamp down on transmission). The stressor, “There is a virus” is information to the Singapore government, whereas it’s uncertainty to Washington DC. 

Another notably antifragile country that’s gotten a lot less attention, but has responded in exactly the way you’d expect, is Switzerland. On February 25th, Switzerland saw their first domestic case; three days later, they’d banned all events of over 1000 people. (Imagine the United States acting with that kind of speed!) Since then they’ve repeatedly recalibrated their testing policy as conditions change in real time; it’s not like they don’t have the virus, but you can see they’re dealing with it in their stereotypically Swiss way. Their signature of well-designed and well-executed antifragility is evident in that a country that puts so much emphasis on individual rights (comparable to the United States) is simultaneously so on the ball with reacting and responding to a new stressor. 

On the other hand, there are other aspects of the American system that are going to shine in the response and aftermath here. The American system, for better or worse, is good at never letting a crisis go to waste. It’s hard to see in real time how today’s reactions will build muscle for tomorrow; the process is going to hurt a lot. But America was built for this. The gym is now. 

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