2020 has been the year of the scientist, or at least the public health scientist.
Science is a method, not a discipline; it includes social science, because social science does at least notionally apply the scientific method.
While being about the discovery of truth, the scientific method implies that truth (with the exception of identities such as mathematical truths) is unattainable. With the scientific method, 'meaningful' propositions are either false or yet to be falsified. The latter 'yet to be falsified' propositions are regarded as provisionally true.
The word 'meaningful' here is a technical word; it relates to propositions that are capable of being tested by 'empirical' evidence. It does not relate to certain other propositions, which are easily understood (but not meaningful in a scientific sense), such as these:
- my favourite colour is 'green'
- Mr X is a bad person
- God exists
- my Christmas present is more valuable than yours
- accounting Method A is better than accounting Method B
The latter example could be regarded as meaningful if an agreed criterion for 'better' is provided. But two different accounting methods can both be 100% accurate.
William McNeill (Plagues and Peoples, 1976) tells us that the suppression of the Third Plague Pandemic was probably the most important achievement, ever, in public health applied science. Most of us know nothing of this, precisely because the Third Plague Pandemic was suppressed.
This was a supreme effort that took place only when (in the 1900s' decade) 'germs' were only just coming to be understood as the principal causes of infectious diseases. Further, it was only this event that enabled the more infamous Second Plague Pandemic to be adequately understood.
First, we must note that 'plague' is the name of a disease that comes in two main forms: 'bubonic' and 'pneumonic'. Bubonic plague is spread by fleas which live on burrowing rodents – which may include rats – for whom the disease is endemic. The more lethal pneumonic plaque is spread much like Covid19, person to person and often through super-spreader events. Unlike Covid19, plague is treatable with antibiotics. But it must be treated quickly; case fatality rates for pneumonic plague were about 90 percent, and fatality could take place within a day of infection.
The first plague pandemic occurred between the years 550 and 750, affected mainly in the Mediterranean coastal areas, and most likely originated in Central Africa.
The second plague pandemic originated in the steppes of Central Asia in the 1330s, and finished in Manchuria in the 1920s; the Manchuria outbreak was the last substantial outbreak linked to that Central Asian contagion reservoir. The most renown episode within this pandemic was the European 'Black Death' of 1348 to 1352.
The third plague pandemic originated in the borderlands of China, Burma (now Myanmar) and India in the 1850s. It festered in China's Yunnan province until it spread to Canton (now Guangzhou) and Hong Kong in the 1890s. From Hong Kong, it spread – via tramp steamers, ship rats and fleas – to seaports all over the world, much as Covid19 spread across the world via people in aeroplanes. While largely suppressed by the 1920s, significant late outbreaks linked to that initial Yunnan source took place in North Africa after World War 2, and in Gujarat, West India, in the early 1990s.
Among the most significant transmissions were those in California, Bombay (now Mumbai) and Sydney. The plague came to New Zealand from Sydney in 1900, with an estimated death toll of 7 people (and many thousands of rats). My partner's great-great-grandfather was a member of the Auckland Health Board that successfully managed the plague outbreak here. The death toll in Australia was about 500, mostly in the Sydney area.
The scientific work was done mainly in Hong Kong and Bombay. It was only then that bubonic plague was scientifically linked to rats and fleas. Ironically, that gave us this huge mental picture of the medieval black death as being linked to medieval poverty, with homes in Europe in that time supposedly infested with rats. Yet few pictures from the time show rats, and transmission patterns away from seaports were inconsistent with rats and fleas as being the only vectors of the disease. It now appears that the Black Death was mainly pneumonic plague, spread person to person by superspreaders. This pattern of transmission was particularly evident in the 1924 Los Angeles outbreak of pneumonic plague.
The third plague pandemic was suppressed – much as the SARS1 coronavirus pandemic of 2003 (more lethal than SARS2, Covid19) was suppressed – through a mix of excellent scientific work and the political will to implement the scientific requirements. (Political overkill did take place, however, especially in British-ruled Hong Kong and India, and with little compensation for those who lost their homes and their livelihoods.) Had that pandemic not been supressed – had pneumonic plague got out of control like the SARS2 coronavirus did in 2020 – the modern world as we know it would have collapsed. In the pre-antibiotic era, this pestilence – both lethal and highly infectious – could have halved the world's population had the science not prevailed.
Unfortunately, as a result of the third plague pandemic, a number of new plague reservoirs formed last century – in Argentina, Peru, South Africa and North America. The North American reservoir covers at least the western two-thirds of the United States. Most human cases in the United States these days occur in the western one-third (and are cured), and in the public estate rather than on farms; farming practices help to minimise the risk of the disease from overflowing from the burrowing rodents into urban human populations. Nevertheless, the fourth plague pandemic, when it comes, will most likely start in the United States, some time after antibiotics have become ineffective and public order has already become tentative.
Many very bad things have been done in the name of science. Eugenics is an applied science that became central to our way of thinking, especially around the years 1870 to 1930. Eugenics is the science of artificial selection; the 'survival of the fittest' enhanced by experts deciding who is fittest, and henceforth who may be permitted to breed.
Eugenics is not false – in the way that alchemy is false. Eugenics is indeed widely applied in farming, and other breeding programmes such as thoroughbred racing horses and pedigree breeding for home pets.
In humans, applied eugenics was called things like 'the improvement of the race'. It formed a pseudo-scientific basis for racism. Eugenics was 'pseudo'-scientific because it was built upon cultural premises about what constituted fitness, and it was built upon a past lack of understanding by scientists of the importance – indeed the biological fitness – of diversity. (We note that eugenics, applied in farming, is also problematic in this regard. Eugenic practices have substantially reduced the diversity of our food crops and domesticated animals, increasing our vulnerability to animal and plant pandemics; and, potentially, to human pandemics.) Good science requires imagination, and few scientists 100 years ago were able to imagine the importance of biological diversity to the fitness of the biosphere.
Eugenics became a cultural-scientific enterprise that built on a particular interpretation of Charles Darwin's published works on biological evolution. While Darwin himself should not be understood as a eugenicist, the 'father' of 'scientific' eugenics was Darwin's cousin Francis Galton. Further, eugenics conflated in the Victorian upper middle class mind with the 'Social Darwinism', an emergent social pseudo-science championed by Herbert Spencer.
Science is the practice of forming provisional truths through the elimination of verified falsehoods. In practice, this process doesn't really work. In social science, it is almost impossible to definitively assign a proposition to the scientific dustbin.
In physical science, falsification has also proved problematic. Doctors – practitioners of medical science – clung onto the idea, long after the miasma theory of infection had been disproved, that they did not need to work in sterile environments. One result was that – in New Zealand in the 1920s when it became normal for women to give birth in hospitals rather than in the home – while the infant mortality rate went down, the maternal mortality rate increased. The problem turned out to be doctors bringing infections with them from general wards into maternity wards.
More generally, the big dichotomy in nineteenth century medical science was the 'miasma theory' versus the 'germ theory' explanation of infectious diseases.
The miasma theory became the mainstay of medical practice for nearly two millennia, following the second century writings of Galen. The theory prevailed until the 1880s, and was still widely believed at the time of the onset of the Third Plague Pandemic. Miasmas were essentially 'bad airs' arising from the ground, especially disturbed or filthy ground. One reason for the ongoing belief in the miasma theory is that it did suggest quarantine and environmental cleanliness as remedies, and these remedies were often effective.
The competing germ theory (or 'contagionist' theory) was first proposed in the sixteenth century, and had many adherents by the eighteenth century. (The case for quarantines was even stronger under the germ theory than under the miasma theory.). But in the nineteenth century, medical science took a major setback; the germ theory was falsely falsified.
William McNeill tells us (p.271) that: "French doctors, when yellow fever broke out in Barcelona in 1822, seized the opportunity to make a definitive test of the contagionist as against the miasmatic school of thought. … They concluded that there was no possibility of contact among the different persons who came down with yellow fever in Barcelona. Thus contagionism seemed to have been fully and finally discredited."
McNeill continues to note that the problem was that "no one as yet imagined [my emphasis] that insects might be carriers of disease". And that "British liberals, in particular, saw quarantine regulations as an irrational infringement of the principle of free trade" and lobbied strongly – and largely successfully – for 'the economy to be prioritised'. This was in the early years of systematised classical political economy; later the same mercantile lobby prevailed during the Irish potato famine.
An important consequence of this false falsification of the germ theory, is that when John Snow discovered that the mid-century London cholera outbreak was caused by contaminated water, his findings were largely ignored. The end of the prevalence of the miasma theory in medical science only came when Robert Koch in 1882 physically and definitively identified the bacteria which caused cholera.
Science – including social science – has become a career for many of our brightest minds. But the necessity to build a career can get in the way of the quality of the science. Further, every now and again, career scientists get much more public attention than they would normally get. Even more important than their new-found media exposure is the fact that these scientists suddenly find that they have the ear of senior decision-making politicians; a select few scientists become public warriors with a cause, rather than cloistered academics researching on the margins of public attentiveness.
One important example of this phenomenon was the 'dry' academic leaders of economic liberalism in the 1980s. (Paul Krugman – himself having a second career as a media economist – has widely discussed the compromises that career-building places on scientific truth in the social sciences.) Treasury in New Zealand at that time preferred to recruit economists from the 'dry' universities, or people who had graduated in other disciplines and could subsequently be inculcated into 1980s' Treasury ways of thinking. And the worse the economy got – thanks to the recommendations of these very people – the more politicians and media looked to these dry economists for explanations and solutions.
In public health today, different countries have adulated different schools of public health. The Swedish public health school has been diametrically opposed to the New Zealand public health school. Yet both schools' leaders have been subject to a sharply heightened media exposure and sense of becoming the military generals of the Covid19 battle. And that can compromise good science.
In the 'battle' against Covid19, there are essentially four pre-vaccine ant-covid measures: lockdowns, border management, contact tracing, and mask wearing. All almost certainly play a role, but the ways these different measures interact can be complex, and unhelpful messaging – much coming from scientists – has contributed to the pandemic. The scientists in particular understand their disciplines, but not the wider pictures of peoples' lives.
Economics can help here – but not the dogmatic kind that ruled over us in the later 1980s and early 1990s. The principal is that an action should be taken if the marginal benefit exceeds the marginal cost of that action. The result of this principle is that restrictive policies should be proportionate as well as effective.
It appears that New Zealand was effective, early, through its lockdowns (through the system of emergency levels); then, border management and contact tracing became critically important to New Zealand's success in 'eliminating' Covid19. In New Zealand, these measures were sufficient; there has been no evidence that community mask-wearing has had any additional effect. Where an unpopular measure has minimal benefits (and masking in New Zealand is revealed as unpopular by the general absence of voluntary masking), it violates the economic principal of balancing marginal costs and marginal benefits. Only politicians, not scientists, should be making these kinds of economic decisions; and the politicians need to be taking advice from a range of relevant perspectives, and not just advice from one group of scientists.
In Taiwan, and some other East Asian countries, the critical measures have been border management and contact tracing. In the absence of lockdowns, masking in crowded indoor environments almost certainly played an additional role in the early stages. But, when a country has eliminated the virus from community transmission (as both New Zealand and Taiwan have), the compulsory wearing of masks can make no difference; and compulsion itself has significant costs, in some cultures more than others. In countries without community covid, the compulsory wearing of galoshes or codpieces would have the same impact on Covid19 as the wearing of masks.
The general application of the economic rule – about marginal benefits and marginal costs – is that contextually ineffective measures should never be taken except under formal emergency conditions that are by their nature characterised by a lack of information, ie a lack of knowing in which contexts the measures are effective.
The expedient approach is to delegate power to disciplinary experts, whose lives are themselves necessarily structured around expedient careers choices. And the expedient approach tends to be to overregulate, rather than to seek an optimal balance; and it doesn't always remove regulations when they are no longer sensible. On the latter point, all emergency-type rules should always be time-limited from the outset, albeit subject to time extensions.
Science plays an important role in our lives, and sciences have much to offer as we seek to improve our lives, and seek to address circumstances that threaten our normal lives. But science is fallible, and no science contains the whole truth about the particular situations we face as we navigate our lives individually and collectively. Sometimes, big mistakes are made in the name of science. Truth is provisional.