【深度交易】塔勒布的反脆弱性和魯棒性
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塔勒布的反脆弱性的定義以及啟示
要真正深入理解塔勒布的著作是非常有難度的。筆者光閱讀索羅斯的金融煉金術“the alchemy of finance” 就讀了七次。同時塔勒布經常會使用很多術語，因此黑天鵝三部曲對於普通的讀者來說，區別於雞湯讀本來說，門檻無疑非常高。事實上兩者的作品在很多地方都有相關性和聯繫。
Via Negativa, or the negative way 亦即通過證明這個不是XXX，來證明這是XXX
通過反向的方式去理解並且對周遭的事物強化其認知。這種否定的方法和索羅斯導師Popper所倡導的理解事物的方式有著異曲同工之妙。
核心在於我們人類習慣了通過歸類法，或是描述法來確認，並且認知一個事物的存在。這種方法自然有他的優勢，其優勢在於通過認知這個東西是什麼，屬於什麼，在什麼範圍內，我們就會擁有安全感。然而其問題在於，正因我們太了解白天鵝，於是我們甚至都沒有思考過黑色的天鵝存在的可能性。
通過否定的方法來認知事物則可以接受更多的可能性，更多的可能性則意味著更多的不確定性（uncertainty) 這意味著我們以謙遜，開放的姿態認知所有的事物，並且潛在接受了事物必將遵循墨菲定律搞砸的特性。一個生態系統強化的方式，在於消化這些不確定性，並且接受其存在，不斷打磨其存在。
反脆弱性Antifragility: 易碎（fragility) 的反面，為何不是堅固，因為往往堅硬的東西都容易磨損，甚至是容易扭曲形變。如同我們的肉體，可以非常肥宅軟嫩，也可以強韌如李小龍，只要願意承受更多的擊打，以及更多的自我訓練。
那麼一個人的體魄，從瘦小肥胖到精瘦強壯，也可以被看成是fragile~ Antifragility的過程。
在塔勒布的書籍中，事物的三個階段，
那就是Fragile — — Robust — — Antifragility而萬物在這三個狀態中轉換。
在塔勒布作品中，有個詞經常出現，那就是Robustness
那麼這個詞是什麼意思呢？
Robustness 魯棒性與穩定性
「魯棒性」並不等同於「穩定性」，「穩定性」概念出現的更早，起源於天體力學特別是太陽系的穩定性研究。魯棒性則是隨著20世紀30年代控制論學科的發展，基於經典穩定性理論逐漸演化出的概念。
穩定性通常意味著「特性隨時間不變化的能力」，魯棒性則常被用來描述可以面對複雜適應系統的能力，需要更全面的對系統進行考慮。例如建築物的穩定性僅僅指建築內部的結構是否穩定，甚至只考慮部分結構的穩定性；魯棒性則要從外部條件和內部結構上整體考量，盡可能將整體的影響納入到計算。
兩者的共性是穩定性和魯棒性均與特定乾擾下的持久程度有關。因此，系統（或物體等）的持久性可被看作魯棒性和穩定性共同關注的特性之一。
While a lot of people casually use the word, not many people have read: Antifragile, where Nassim Taleb defines it for us.
雖然很多人隨便使用該詞，但很少有人讀過：《抗脆弱性》（Nassim Taleb期權交易大師在其中為我們定義）。
Just as being clear on what constitutes a black swan allows us to better discuss the subject, so too will defining antifragility.
正如清楚地了解黑天鵝的構成可以使我們更好地討論這個主題一樣，定義反脆弱性也是如此。
The classic example of something antifragile is Hydra, the Greek mythological creature that has numerous heads. When one is cut off, two grow back in its place.
抵抗脆弱的東西的經典例子是九頭蛇（Hydra），這是希臘神話中有許多頭顱的生物。當其中一個被切斷時，兩個將恢復原位。
From Antifragile: Things That Gain from Disorder:
來自反脆弱性：我們從混亂中學到的東西
Some things benefit from shocks; they thrive and grow when exposed to volatility, randomness, disorder, and stressors and love adventure , risk, and uncertainty. Yet, in spite of the ubiquity of the phenomenon, there is no word for the exact opposite of fragile. Let us call it antifragile. Antifragility is beyond resilience or robustness. The resilient resists shocks and stays the same; the antifragile gets better. This property is behind everything that has changed with time: evolution, culture, ideas, revolutions, political systems, technological innovation, cultural and economic success, corporate survival, good recipes (say, chicken soup or steak tartare with a drop of cognac), the rise of cities, cultures, legal systems, equatorial forests, bacterial resistance … even our own existence as a species on this planet. And antifragility determines the boundary between what is living and organic (or complex), say, the human body, and what is inert, say, a physical object like the stapler on your desk.
有些事物會從衝擊中受益；當這些事物暴露於波動性，隨機性，混亂和壓力下時，它們會蓬勃發展，並且喜歡冒險，冒險和不確定性。然而，儘管這種現象無處不在，但對於脆弱的確切對立面卻沒有字可言。讓我們稱之為反脆弱性。抗脆弱性不只是彈性或堅固性。彈性能抵抗衝擊並保持不變；抗脆性會變得更好。
這個屬性是隨時間變化的一切的背後：進化，文化，思想，革命，政治制度，技術創新，文化和經濟上的成功，企業生存，良好的配方（例如，雞湯或or牛肉配上乾邑白蘭地），城市，文化，法律制度，赤道森林，細菌抵抗力的興起……甚至我們作為這個星球上的物種而存在。防碎性決定了生命和有機物（或複雜物）（例如人體）和惰性物質（例如桌上的訂書機）之間的界限。
The antifragile loves randomness and uncertainty, which also means — crucially — a love of errors, a certain class of errors. Antifragility has a singular property of allowing us to deal with the unknown, to do things without understanding them — and do them well. Let me be more aggressive: we are largely better at doing than we are at thinking, thanks to antifragility. I’d rather be dumb and antifragile than extremely smart and fragile, any time.
反脆弱性偏愛隨機性和不確定性，從根本上講，這也意味著對錯誤的熱愛，對某種錯誤的熱愛。反脆弱性具有使我們與未知事物打交道，在不了解情況的情況下做事並做好事的獨特屬性。讓我更加積極進取：由於反脆弱性，我們在做事上比在思考上要好得多。我寧願極端愚蠢和脆弱，也不願隨時變得異常聰明和脆弱。
It is easy to see things around us that like a measure of stressors and volatility: economic systems , your body, your nutrition (diabetes and many similar modern ailments seem to be associated with a lack of randomness in feeding and the absence of the stressor of occasional starvation), your psyche. There are even financial contracts that are antifragile: they are explicitly designed to benefit from market volatility.
``我們周圍的事物很容易看到，就像壓力源和波動性的度量標準一樣：經濟系統，我們的身體，我們的營養水平（糖尿病和許多類似的現代疾病似乎與餵養缺乏隨機性和缺乏壓力源有關偶爾的飢餓），我們的靈魂。甚至有些金融合同都非常脆弱：它們明確地旨在從市場動盪中受益。
Antifragility makes us understand fragility better. Just as we cannot improve health without reducing disease, or increase wealth without first decreasing losses, antifragility and fragility are degrees on a spectrum.
抗脆弱性使我們更好地了解脆弱性。正如我們在不減少疾病的情況下不能改善健康情況，或在不先減少損失的情況下增加財富一樣，抗衰老性和脆弱性也是生命本身的維度。
Nonprediction 非預測性
By grasping the mechanisms of antifragility we can build a systematic and broad guide to nonpredictive decision making under uncertainty in business, politics, medicine, and life in general — anywhere the unknown preponderates, any situation in which there is randomness, unpredictability, opacity, or incomplete understanding of things.
通過掌握反脆弱性的機制，我們可以為在商業，政治，醫學和生活普遍存在不確定性的情況下的非預測性決策制定係統。廣泛的指南，無論是未知數佔優勢的任何地方，任何情況都存在隨機性，不可預測性，不透明性或 對事物的理解不完整。
It is far easier to figure out if something is fragile than to predict the occurrence of an event that may harm it. Fragility can be measured; risk is not measurable (outside of casinos or the minds of people who call themselves “risk experts”). This provides a solution to what I’ve called the Black Swan problem — the impossibility of calculating the risks of consequential rare events and predicting their occurrence. Sensitivity to harm from volatility is tractable, more so than forecasting the event that would cause the harm. So we propose to stand our current approaches to prediction, prognostication, and risk management on their heads.
``比起預測可能會危害它的事件的發生，要弄清楚某事是否易碎要容易得多。易碎性可以測量；風險是無法衡量的（在賭場或自稱為“風險專家”的人的頭腦之外）。這為我所謂的“黑天鵝”問題提供了一種解決方案，即無法計算必然發生的罕見事件的風險並預測其發生的可能性。對波動造成的損害的敏感性很容易處理，而不是預測會造成損害的事件。因此，我們建議將當前的預測，預後和風險管理方法放在首位。
In every domain or area of application, we propose rules for moving from the fragile toward the antifragile, through reduction of fragility or harnessing antifragility. And we can almost always detect antifragility (and fragility) using a simple test of asymmetry : anything that has more upside than downside from random events (or certain shocks) is antifragile; the reverse is fragile.
在每個應用領域或領域，我們都提出了通過減少脆弱性或利用抗脆弱性從脆弱性轉向抗脆弱性的規則。而且，我們幾乎總是可以使用簡單的不對稱性測試來檢測抗脆弱性（和脆弱性）：任何比隨機事件（或某些衝擊）具有更大利弊的東西都是抗脆弱性；相反是脆弱的。
Deprivation of Antifragility
剝奪抗脆弱性
Crucially, if antifragility is the property of all those natural (and complex) systems that have survived, depriving these systems of volatility, randomness, and stressors will harm them. They will weaken, die, or blow up. We have been fragilizing the economy, our health, political life, education, almost everything … by suppressing randomness and volatility. … stressors. Much of our modern, structured, world has been harming us with top-down policies and contraptions (dubbed “Soviet-Harvard delusions” in the book) which do precisely this: an insult to the antifragility of systems. This is the tragedy of modernity: as with neurotically overprotective parents, those trying to help are often hurting us the most (see iatrogenics)
至關重要的是，如果抗脆弱性是所有倖存下來的自然系統（和復雜系統）的財產，那麼剝奪這些系統的揮發性，隨機性和壓力會損害它們。它們會變弱，死亡或爆炸。我們一直在壓制經濟，我們的健康，政治生活，教育，幾乎所有事物的脆弱……通過壓制隨機性和波動性。 ……壓力源。我們現代的，結構化的世界中的許多人一直在採用自上而下的政策和手段（在書中稱其為“蘇維埃-哈佛錯覺”）來傷害我們，這恰恰是在這樣做：侮辱系統的抗脆弱性。這是現代性的悲劇：就像神經保護過度的父母一樣，那些試圖幫助父母的人對我們的傷害最大（參見醫源性疾病）。
Antifragile is the antidote to Black Swans. The modern world may increase technical knowledge, but it will also make things more fragile.
反脆弱性是黑天鵝的解毒劑。我們的現代社會中即使富有現金的技術和知識，但也會使事情變得更加脆弱。
… Black Swans hijack our brains, making us feel we “sort of” or “almost” predicted them, because they are retrospectively explainable. We don’t realize the role of these Swans in life because of this illusion of predictability. Life is more, a lot more, labyrinthine than shown in our memory — our minds are in the business of turning history into something smooth and linear, which makes us underestimate randomness. But when we see it, we fear it and overreact. Because of this fear and thirst for order, some human systems, by disrupting the invisible or not so visible logic of things, tend to be exposed to harm from Black Swans and almost never get any benefit. You get pseudo-order when you seek order; you only get a measure of order and control when you embrace randomness.
……黑天鵝事件本身劫持了我們的大腦，使我們感到我們“某種”或“幾乎”預言了它們，因為我們得以通過歷史回溯去解釋這些黑天鵝事件的發生。由於這種可預測性的幻想，我們沒有意識到這些天鵝在生活中的作用。生活比我們記憶中所顯示的更多，更多的是迷宮般的迷宮-我們的思想是將歷史變成平滑而線性的事物，這使我們低估了隨機性。但是，當我們看到它時，我們會害怕並反應過度。由於對秩序的這種恐懼和渴望，某些人類系統通過破壞事物的無形或無形邏輯，往往會受到黑天鵝的傷害，幾乎永遠得不到任何好處。當我們一味尋求平穩的秩序時，我們往往會得到虛偽的秩序和平衡；當我們接受隨機性時，我們才會得到真正可控的秩序。
Complex systems are full of interdependencies — hard to detect — and nonlinear responses. “Nonlinear” means that when you double the dose of, say, a medication, or when you double the number of employees in a factory, you don’t get twice the initial effect, but rather a lot more or a lot less. Two weekends in Philadelphia are not twice as pleasant as a single one — I’ve tried. When the response is plotted on a graph, it does not show as a straight line (“linear”), rather as a curve. In such environments, simple causal associations are misplaced; it is hard to see how things work by looking at single parts.
複雜的（金融）系統充滿了相互依存關係（難以檢測）和非線性響應。 “非線性”是指，如果我們將某種藥物的劑量加倍，或者將工廠中的員工人數加倍，我們所得到的初始效果將不會達到兩倍，而是會比預期更多的多，甚至是比預期少的多。舉例來說，在費城所度過的兩個週末假期並不像一個週末那麼愉快。將市場反應繪製在圖形上時，它不會顯示為直線（“線性”），而是顯示為曲線。
在這樣的環境中，簡單的因果關聯被放錯了位置。如果我們僅僅著眼於單個部分就很難看清整個系統的工作原理。
Man-made complex systems tend to develop cascades and runaway chains of reactions that decrease, even eliminate, predictability and cause outsized events. So the modern world may be increasing in technological knowledge, but, paradoxically, it is making things a lot more unpredictable.
人造的複雜系統往往會形成級聯和失控的反應鏈，這些反應會減少甚至消除，可預測性並導致特大事件。因此，即便在現代文明中我們掌握了很多先進技術，但自相矛盾的是，這些黑天鵝事件使系統本身變得更加不可預測。
An annoying aspect of the Black Swan problem — in fact the central, and largely missed , point — is that the odds of rare events are simply not computable.
黑天鵝問題的一個令人煩惱的方面-實際上是中心問題，而這一點在很大程度上是被遺漏的-是罕見事件的機率根本無法計算。
Robustness is not enough.
僅僅關注魯棒性是不足的。
Consider that Mother Nature is not just “safe.” It is aggressive in destroying and replacing, in selecting and reshuffling . When it comes to random events, “robust” is certainly not good enough. In the long run everything with the most minute vulnerability breaks, given the ruthlessness of time — yet our planet has been around for perhaps four billion years and, convincingly, robustness can’t just be it: you need perfect robustness for a crack not to end up crashing the system. Given the unattainability of perfect robustness, we need a mechanism by which the system regenerates itself continuously by using, rather than suffering from, random events, unpredictable shocks, stressors, and volatility.
大自然本身不僅是“安全的”。它在銷毀和替換，選擇和改組方面非常積極。當涉及隨機事件時，“健壯或是強韌”當然還不夠好。從長遠來看，考慮到時間的殘酷性，所有具有最微小漏洞的漏洞都將破滅，但我們的星球已經存在了大約40億年，而且令人信服的是，魯棒性不能僅僅是它：您需要完美的魯棒性來確保裂紋不最終導致系統崩潰。鑑於無法實現完美的魯棒性，我們需要一種機制，使系統通過使用（而不是遭受）隨機事件，不可預測的衝擊，壓力和波動來不斷地自我再生。
Fragile and antifragile are relative — there is no absolute. You may be more antifragile than your neighbor, but that doesn’t make you antifragile.
脆弱性和反脆弱是相對性的，沒有絕對的關係。但這並不能使我們更加脆弱。
“Complex systems are weakened, even killed, when deprived of stressors.”
— Nassim Taleb
“缺乏壓力源時，複雜的系統會被削弱，甚至被殺死。”－ Nassim Taleb
The Triad is FRAGILE — ROBUST — ANTIFRAGILE.
三部曲是脆弱的-堅固的-反抗的。
Source: Antifragile
Here’s an example
如下是例子
All of this can lead to some pretty significant conclusions. Often it’s impossible to be antifragile, but falling short of that you should be robust, not fragile. How do you become robust? Make sure you’re not fragile. Eliminate things that make you fragile. In an interview, Taleb offered some ideas:
所有這些都可以得出一些相當重要的結論。通常不可能做到反脆弱，但要做到這一點，就應該堅強而不是脆弱。那麼如何變得健壯？確保不脆弱。消除使我們脆弱的事物。在一次採訪中，塔勒布提出了一些想法：
You have to avoid debt because debt makes the system more fragile. You have to increase redundancies in some spaces. You have to avoid optimization. That is quite critical for someone who is doing finance to understand because it goes counter to everything you learn in portfolio theory. … I have always been very skeptical of any form of optimization. In the black swan world, optimization isn’t possible. The best you can achieve is a reduction in fragility and greater robustness.
我們必須避免債務，因為過多的債務會使系統更加脆弱。我們同時必須在某些空間中增加冗餘。而必須去避免優化。對於從事財務工作的人來說，這很關鍵，因為所有這些準則都與我們從傳統投資組合理論中學到的一切背道而馳。 ……我一直對任何形式的優化都持懷疑態度。
在黑天鵝世界中，我們無法進行優化。而可以實現的最佳結果是減少脆弱性並提高魯棒性。
