In 1958, as part of his Great Leap Forward, Chairman Mao Zedong initiated a hygiene campaign throughout China. In particular, Mao had decided that China needed to do something to prevent the spread of diseases, so a significant part of his initiative was the ‘Four Pests Campaign’. The campaign involved the systematic extermination of rats, flies and mosquitoes (three of the four pests). And as for the fourth pest, that distinction went to the sparrows.

Kill the sparrows

By the time the Great Leap Forward began, the collectivisation of Chinese agriculture was in full swing. Chairman Mao believed that the two fundamental pillars of China’s industrialisation were grain and steel production, and he belonged to a faction within the People’s Party which had long argued that the best way to finance China’s industrialisation was for the government to establish a monopoly over the supply and distribution of grain. Unfortunately for the sparrows, because they were often seen eating grain seeds, it had become conventional wisdom that the Eurasian Tree Sparrow was a threat to grain production.

So when Chinese scientists calculated that each wild sparrow consumed 4.5kg of grain a year – and that for every million sparrows killed, there would be food for 60,000 people – the population of China was quickly mobilised to drive the sparrows into the air, exhaust them in flight, and slaughter them as they fell to the ground.

Here’s an extract from a Shanghai newspaper at the time:

“On the early morning of December 13, the citywide battle to destroy the sparrows began.  In large and small streets, red flags were waving.  On the buildings and in the courtyards, open spaces, roads and rural farm fields, there were numerous scarecrows, sentries, elementary and middle school students, government office employees, factory workers, farmers and People’s Liberation Army shouting their war cries.  In the Xincheng district, they produced more than 80,000 scarecrows and more than 100,000 colorful flags overnight.  The residents of Xietu road, Xuhui distrct and Yangpu road Yulin district also produced a large number of motion scarecrows.  In the city and the outskirts, almost half of the labor force was mobilized into the anti-sparrow army.  Usually, the young people were responsible for trapping, poisoning and attacking the sparrows while the old people and the children kept sentry watch.  The factories in the city committed themselves into the war effort even as they guaranteed that they would maintain production levels.  In the parks, cemeteries and hot houses where there are fewer people around, 150 free-fire zones were set up for shooting the sparrows.  The Nanyang Girls Middle School rifle team received training in the techniques for shooting birds.  Thus the citizens fought a total war against the sparrows.  By 8pm tonight, it is estimated that a total of 194,432 sparrows have been killed.”

By the end of the campaign, hundreds of millions of sparrows had been killed, and the sparrow virtually disappeared from China.

Cue: Famine

According to some, the program was at first successful, because the crop yields for grain and rice rose slightly in the few months after the sparrow extinction program started.

But then in the absence of the sparrows, the population of insects bloomed, and plagues of them ate their way through China’s agricultural production.

At which point: “partly as a consequence of starvation due to crop failure, 35 million Chinese people died.”

Here’s the Smithsonian:

The great leap forward leapt backward, which is when a few scientists in China began to notice a paper published by a Chinese ornithologist before the sparrows were killed. The ornithologist had found that while adult tree sparrows mostly eat grains, their babies, like those of house sparrows, tend to be fed insects. In killing the sparrows, Mao and the Chinese had saved the crops from the sparrows, but appear to have left them to the insects. And so Mao, in 1960, ordered sparrows to be conserved (replacing them on the list of four pests with bedbugs).

This particular lesson in the law of unintended consequences has been sitting deeply with me in the last week.

The trouble is: conventional wisdom is so appealing. There is a dash of fact interspersed with a plethora of anecdote – and anything that runs contrary to it is seen as rumour-mongering, or agenda-driven, or dishonest. From what I’ve read, the Chinese scientists that opposed the eradication of the sparrow were condemned as Anti-Mao and Anti-The-Great-Leap-Forward, and they were purged alongside the pests.

The Lesson: We’re More Ignorant Than Not

My concern is that we’ve missed the most important lesson that history has to teach. At every point in our past, the average man on the street has not gone about his daily life suspecting that he knows almost nothing about the world.

Instead, he has felt advanced and superior to those that came before him. He has known better ways to farm and better ways to treat illness than any of his ancestors. Rather, it is his ancestors that were dull and uninformed. And barely lucky enough to scrape their way to adulthood and an early death.

Today, we too look back on the history of human knowledge with a degree of condescension. After all, comparatively speaking, the accomplished scientists of the 1800s knew less about the world and the Universe than today’s school children.

But what we haven’t really absorbed is that we’re also going to be those dull and uninformed buffoons to someone someday soon. And even if we have antibiotics, transplant surgery, MRIs, the internet, email, aeroplanes, high-yield crop production, iPhones and electricity – the long-term trend of human knowledge suggests that almost everything that we think we know will be wrong. And even what we get ‘right’ will appear accidental, because it will have been based on demonstrably false premises.

Yet we cling to ‘truths’ and ‘conventional wisdoms’ as though they are indefinitely and infinitely inviolable – defending them against any contradictory view with waves of ad hominem purges.

It’s madness that we spend so much time asserting what is right, without even the slightest hint of self-doubt.

Especially as we’re almost certainly going to be wrong.

Rolling Alpha posts opinions on finance, economics, and sometimes things that are only loosely related. Follow me on Twitter @RollingAlpha, and on Facebook at www.facebook.com/rollingalpha. Also, check out the RA podcast on iTunes: The Story of Money.