Coronavirus: A Black Swan?


Describing uncertainty – why coronavirus is neither a ‘black swan’ nor a low probability event

The manuscript of Radical Uncertainty was finished well before anyone had heard of the novel Coronavirus. However, the current pandemic (and attempts to deal with it) is a good example of the radical uncertainty we discuss. I will write more soon; for now, I’m posting the relevant extracts from the book here. If you’re interested (or need something to read when you’re self-isolating!) you can buy a copy here.

Unknown unknowns (pp. 38-40)

At the opposite pole of uncertainty from true randomness are the genuinely unknown unknowns.  Taleb’s metaphor of the ‘black swan’ describes the unknown unknowns of business and finance, which are no less important than those of aviation.  The origin of the metaphor is that Europeans believed all swans to be white – as all European swans are – until the colonists of Australia observed black swans.  A century ago, a telephone that would fit in your pocket, take photographs, calculate the square root of a number, navigate to an unknown destination, and on which you could read any of a million novels, was not improbable.  It was just not within the scope of imagination or bounds of possibility.  Before the wheel was invented (perhaps by the Sumerians, ancient Iraqis, around 3,500 BC) no one could talk about the probability of the invention of the wheel and afterwards there was no uncertainty to discuss; the unknown unknown had become a known known.  To identify a probability of inventing the wheel is to invent the wheel.  To ask, either before or after the event, ‘what was the probability of such an event?’ is not an intelligible question.[1]  

True ‘black swans’ are states of the world to which we cannot attach probabilities because we cannot conceive of these states.  The dinosaurs fell victim to an unknown unknown – even as they died they did not know what had happened to them.  Human extinction will more likely come about in another way.  Martin Rees, a Cambridge scientist and former Astronomer Royal, has founded a Centre for the Study of Existential Risk, to identify such potential threats and suggest measures to mitigate them.  He warns of the possibility of runaway climate change, pandemics, artificial intelligence and robots which run out of control.  These are threats we can at least perceive.  But the observation of a black swan was not a low probability event; it was an unimaginable event, given European knowledge of swans.  As the convict colonists boarded the First Fleet, no one would plausibly have offered, or accepted, a wager of the kind “I bet you one thousand to one all the swans in Australia are white”.  Natural phenomena are more likely than social ones to be the result of stationary processes – the structure of the physical world changes less than do global business, finance and politics.  But the impact of a pandemic is determined as much or more by the state of medical knowledge than by the pathogens of disease.  The Black Death will not recur – plague is easily cured by antibiotics (although the effectiveness of antibiotics is under threat) – and a significant outbreak of cholera in a developed country is highly unlikely.  But we must expect to be hit by an epidemic of an infectious disease resulting from a virus which does not yet exist.  To describe catastrophic pandemics, or environmental disasters, or nuclear annihilation, or our subjection to robots, in terms of probabilities, is to mislead ourselves and others.  We can talk only in terms of stories.  And when our world ends, it will likely be the result, not of some ‘long tail’ event arising from a low probability outcome from a known frequency distribution, not even from one of the contingencies hypothesised by Martin Rees and colleagues, but as a result of some contingency we have failed even to imagine. 

In 1895, Lord Kelvin, one of the greatest physicists of his age, wrote that “I have not the smallest molecule of faith in aerial navigation other than ballooning or of expectation of good results from any of the trials we hear of.  So you will understand that I would not care to be a member of the Aëronautical Society.”[2]  His observation was followed in an embarrassingly short time by the first controlled flight, covering 300 yards and just under a minute long.  And today, two centuries after the First Fleet reached Botany Bay with no expectation of observing black swans, an Airbus A380 weighing 360 tonnes can carry 550 passengers over 9000 miles from England to Australia.  Something that would have been incomprehensible even one hundred years ago.  The next hundred years will be no less radically uncertain.

Modelling epidemics – look for critical parameters, not predictions (pp. 375-6)

The first human exposure to HIV is thought to have occurred in the 1920s.  But it was not until 1981, when unusual clusters of PCP (a rare lung infection) in 5 gay men in San Francisco were reported, that the phenomenon we know today was identified.  Tasked with creating a model to guide policymakers as to how the disease would spread and the level of intervention necessary, the WHO designed a complex model informed by the latest country-by-country demographic data.   A far simpler model was developed by mathematicians Robert May and Roy Anderson, who came up with more pessimistic projections for the spread of HIV. Unfortunately their projections proved much closer to the eventual outturns.[3]  AIDS infections accelerated across the world, causing particular harm in Southern Africa: in 1990 there were estimated to be 120,000 people living with AIDS, a number which had grown to 3.4 million by 2000.  The number of new HIV infections had risen ninefold.[4]  The world was, it seemed, a much less stable place than the WHO model had assumed.

Why did the (apparently) more sophisticated WHO model fail compared to May and Anderson’s simple one?  The key factors governing the spread of disease included the probability of an infected person transferring the infection to another person.  May and Anderson realised that the probability of infecting another person had two components: the probability that any sexual act would transfer infection; and how many sexual partners infected people had.  It was crucial to distinguish between the two.  An HIV-positive sex worker who sleeps with 10 different people is more likely to spread the disease than someone who sleeps with the same person ten times.  But the WHO model did not make this distinction, and that is why its predictions of the spread of AIDS were, tragically, inaccurate.  May and Anderson had asked “what is going on here?”.   The WHO model had focussed on the detailed demographic data the modellers understood, rather than looking at what really mattered – the different sexual habits of affected groups.

Why – whatever President Trump may think – Europe is better placed to deal with coronavirus than the United States

Denmark as top nation (pp. 426-8)

At a conference in an English country house on the topic of future geopolitics, pundits emphasised the significance of the coming competition between China and the United States to be ‘top nation’, as Sellar and Yeatman put it in their classic satire on British history 1066 And All That.[5]  Provocatively, one of the authors observed that for many modern Europeans, Denmark was ‘number one’ – rich, socially cohesive, with enviable infrastructure and environmental standards – and it regularly features near the top in surveys of the world’s happiest populations.  ‘Hygge’, sometimes defined as ‘cozy contentment and well-being through enjoying the simple things in life’, has recently become one of the few Danish words to enter the English language.

But Denmark is so boring, responded a former ambassador to Denmark.  And, for an ambassador, Denmark is boring.  Its politics are of no global significance, its economy is stable, there is no need for embassies to respond to urgent cables or consultations.  The life of the ambassador was a round of receptions at which congenial guests spoke excellent English.  By contrast, Zimbabwe is not boring either for ambassadors or the general population, but the general population wishes it were.  Denmark provides its inhabitants with a secure reference narrative – they do not feel threatened by loss of income, or crippling medical bills, or terrorist threats, or insecure retirement.  Natural disasters are rare and when they occur efficient emergency services are there to help.  What was profoundly shocking about the devastation in New Orleans caused by Hurricane Katrina in 2005 was that the resources of the nation with the world’s largest GDP were not organized to protect the fundamental needs, far less the reference narrative, of its citizens in time of crisis.  And that is why almost all Europeans are puzzled by the American idea that the provision of universal health care should be controversial.

There is a strand of thought which associates the extraordinary innovative capacity of the US economy with this reluctance of its governments to provide the social insurance against risk – in the broadest sense –  which is taken for granted in Denmark, and most European countries.  But we need to probe deeper.  Bill Gates did not drop out of Harvard to set up Microsoft because the alternative was unemployment, or because he feared an illness that would threaten his bank balance as well as his life; rather the opposite.  He was able to follow his dream because he had little fear of these things; he was the son of a prosperous attorney and already marked for success by his education.  Leland Stanford had qualified as an attorney before moving to California.  Peter Thiel, the putative refugee in  a New Zealand bunker, and  perhaps the most outspoken representative of Silicon Valley libertarians, also began his career as a lawyer (he graduated from Stanford University), clerking for a federal circuit judge, and practising with a premier securities law firm before founding PayPal.

In the nineteenth century, when poor but adventurous European immigrants flooded into the United States, there was some foundation to the narrative of the boy who risks all, but whose grit and enterprise creates a great business and makes him rich.  Johann Suter tried – and failed; Andrew Carnegie succeeded.  But as with the myth of log cabin to White House, real examples are few.  If PayPal had failed, and it might have (many attempts were made to develop new payments systems for the digital age and few succeeded), Thiel might not have been a billionaire but would still have enjoyed a much more comfortable lifestyle than most of his fellow Americans.

America’s innovative hegemony is in technology.  You will find more adventurous food in Copenhagen than in Chicago or even New York (except in that city’s Scandinavian restaurants), and in the Danish capital today there is a cultural milieu unmatched in any US city of comparable size.  Denmark – and Italy – stand out for creative design.  If we look for innovation in art, or literature, or music, our search extends across the developed world.  But not to Zimbabwe, or Syria.  While Borgia and Sforza had reason for constant fear for their lives, Leonardo and Michelangelo did not; and neither had to worry about ZANU-PF goons or chemical bombs.

The people of Denmark can enjoy uncertainty because they experience little risk and are secure in their reference narratives.  Far from representing a threat, uncertainty can be the source of all that makes life worth living.  Delight in discovering a previously unknown place while on holiday.  Or a new book, or piece of music, or friend.  In places such as Zimbabwe or Syria, risk dominates.  The collapse of the Zimbabwean economy and the civil war in Syria deprived much of the population of any secure reference narrative; many are refugees in South Africa or Europe and those who remain in their own countries are fearful of what tomorrow will bring.  In the absence of a secure reference narrative, uncertainty is scary.  Within the context of such a narrative, uncertainty – the prospect of new experiences – can be a source of joy rather than despair.

[1] Alasdair MacIntyre attributes the illustration to Karl Popper, who describes the impossibility of predicting the invention of the wheel (MacIntyre 2003 p. 93).

[2] Thomson (1896).  There is no evidence for many of the most hubristic quotes attributed to him, such as “X-rays will prove to be a hoax”, but inventions appear to have been a weak spot: when he heard about wireless he snorted “Wireless is all very well but I’d rather send a message by a boy on a pony.” (Marconi 2001 p. 40).

[3] May (2004) p. 792.

[4] UNAIDS (2018).

[5] Sellar and Yeatman (1930).

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