A few weeks ago, I wrote an article about the curious fact that anti-GMO activists are unmoved by science that shows genetically modified crops are both beneficial and safe. On the contrary, it hardens their position. The anti-GMO activist group I cited as an example responded, unimaginatively calling me an industry shill.

I rebutted their response, showing why their allegation that I cherry-picked industry-funded papers falls flat under even cursory examination, and why glyphosate, a weed-killer against which some GM crops are resistant, is remarkably safe. And as I pointed out in 2016, GMOs are good for the environment, too.

A far more interesting argument against GMOs is that of celebrated author Nassim Taleb, who has made a career out of speculating about the risks posed by extremely unlikely events. His books include Fooled by Randomness, on the fallibility of human knowledge, and Black Swan, on the impact of the highly improbable.

Taleb has argued that GMOs ought to be regulated under the precautionary principle because, as he puts it, the risks associated with them have the potential to cause “global ruin”.

In risk management parlance, he claims that GMOs pose a very low risk of very large hazards. A hazard is something that has the potential to cause harm. A risk is a likelihood that a hazard actually will cause harm. When you get in a car, for example, the hazard is dying or being seriously injured. The risk is the chance that this will happen.

There are various statements of the precautionary principle. It was first codified in 1982, in the UN World Charter for Nature:

“Activities which are likely to pose a significant risk to nature shall be preceded by an exhaustive examination; their proponents shall demonstrate that expected benefits outweigh potential damage to nature, and where potential adverse effects are not fully understood, the activities should not proceed.”

Another definition reads as follows:

“Regulation should presumptively be applied when an activity or product poses serious threats to human health or the environment, even if scientific uncertainty precludes a full understanding of the nature or extent of the threats; and the burden of overcoming the presumption in favour of regulation lies with the proponent of the risk-creating activity or product.”

The precautionary principle has been adopted by many legislative and regulatory bodies, most notably in the Treaty on the Functioning of the European Union. The EU’s version is weak, in that it leaves action up to the discretion of the authorities responsible for risk management. In most cases, the onus is on consumers or consumer associations to demonstrate that there is a risk. In some cases, however, and particularly with medicines, pesticides and food additives, the producer, manufacturer or importer may be required to prove the absence of danger.

The precautionary principle has been widely criticised for promoting regulatory paranoia and paralysing progress.

No matter its formulation, it is quite vague, in that it does not specify how serious a potential threat has to be to trigger it, under which conditions the burden of proof shifts from those claiming to identify hazards to those proposing an activity or new technology, or what kind of regulation is appropriate.

In most cases, the precautionary principle considers the dangers of an activity, but does not consider the foregone benefits should an activity be prohibited. We do not forgo driving, even though death is an extreme hazard since the risk of death is low enough for most of us. We licence medicines for beneficial uses, even when there is a significant risk of serious side-effects, up to and including death.

A grave objection to the precautionary principle is the logical difficulty of proving a negative. While it is possible to prove that a danger exists by pointing to an example or a plausible mechanism of action, one cannot do the same to prove that danger does not exist.

This is connected to the problem of induction, which is commonly illustrated by the black swan analogy, after which Taleb’s book is titled. The statement “all swans are white” was held to be true, until black swans were discovered in Australia in the 17th century.

Establishing evidence of “the absence of danger”, as the EU formulation of the precautionary principle requires, is difficult. Proving that a proposed danger is a theoretical impossibility is rarely possible. No matter how much evidence of safety one amasses, it does not prove that no danger exists, just as any number of white swans did not prove that black swans do not exist.

The precautionary principle, therefore, places an impossible (or at least unreasonable) burden of proof on the proponents of an activity or new technology. In this, it is analogous to establishing guilt in a court of law. It is a foundational principle of legal justice to expect the prosecution to prove guilt beyond a reasonable doubt before convicting and sentencing someone. The precautionary principle would imprison people upon mere suspicion that they had done something wrong, unless they could prove their innocence beyond a reasonable doubt.

In the academic formulation of Taleb’s argument, he proposes a “non-naive version of the precautionary principle”. He still holds that “the burden of proof about absence of harm falls on those proposing the action,” but adds that he believes that “the [precautionary principle] should be evoked only in extreme situations: When the potential harm is systemic (rather than localised) and the consequences can involve total irreversible ruin, such as the extinction of human beings or all life on the planet”.

In cases where there merely is a quantifiable risk of localised harm, he would apply normal risk management techniques such as cost-benefit analysis. If there is any risk of ruin, however, the statistical probability of it happening will eventually approach one. This, he believes, calls for the application of the precautionary principle.

He admits that the burden of proof about the absence of harm, which he says should fall on those proposing an action, is an impossible standard to meet: “In some classes of complex systems, controlled experiments cannot evaluate all of the possible systemic consequences under real-world conditions. In these circumstances, efforts to provide assurance of the ‘lack of harm’ are insufficiently reliable. This runs counter to both the use of empirical approaches (including controlled experiments) to evaluate risks, and to the expectation that uncertainty can be eliminated by any means.”

Once he has established when to apply the precautionary principle, he uses two examples, namely nuclear power and GMOs. In considering the regulation of nuclear power, he says, the precautionary principle is not warranted. Potential nuclear hazards, such as meltdowns and waste, can be large, but are localised and quantifiable. They pose no systemic threat to all of humanity.

The use of GMOs, however, should fall under the precautionary principle, Taleb argues, because of “the widespread impact on the ecosystem and the widespread impact on health”. In addition, he says, monoculture (planting a single crop variety on a large scale) poses systemic risks to the world’s food system, and the use of genetic engineering “dramatically increases the risks being taken”.

The question is whether his fears of ruin are indeed warranted. If they aren’t, the precautionary principle would prohibit a technology that has substantial and proven benefits.

“Ecologically, in addition to intentional cultivation, GMOs have the propensity to spread uncontrollably, and thus their risks cannot be localised,” says Taleb. This is false. Very few cultivated crops have the propensity to spread uncontrollably. They are adapted for traits favourable to large-scale agriculture, but survival in the wild is not one of them. If it was, farming would be a lot easier than it is.

Although environmental contamination with bio-engineered traits is possible and poses some risk which ought to be mitigated, there is no reason to believe that it can lead to catastrophic consequences, which is Taleb’s threshold for applying the precautionary principle.

In the sole paragraph discussing health risks, Taleb gives no evidence that there is a plausible hazard that is any greater than the dangers introduced by cross-breeding or selecting random mutations. He uses the term “chemical” instead of “gene”, which is hardly suggestive of someone who knows what he’s talking about. He adds a spurious claim that GMOs increase the use of pesticides and that they “cannot be washed away”, neither of which is true.

He claims that unlike with conventional crop breeding, in which evolutionary selection restricts the spread of harmful mutations, genetic engineering “unintentionally manipulate[s] large sets of interdependent factors at the same time, with dramatic risks of unintended consequences”.

In fact, genetic engineering manipulates very few specific genes – usually only one – of which the purpose is well-known. By contrast, conventional breeding changes numerous genes randomly. He does not explain why a harmful GM mutation would not be selected against in an evolutionary manner, just as farmers would do with harmful traits in conventionally bred crops.

In fact, he offers no plausible reason why GM crops should be considered hazardous at all, let alone so hazardous as to risk the extinction of the human species.

The argument about monoculture is especially trite. He is concerned that widespread use of specific GMO strains could collapse the entire food system, should disease or some such misfortune strike the crops. Yet his real-world example dates from the 19th-century potato blight, more than a century before genetic engineering was introduced.

He neglects to mention that genetic diversity in commodity crops has actually increased since the advent of GMOs. Monoculture farming has enabled farmers to produce enough crops to feed an ever-growing population, but they are well aware of the risks this entails. A great deal of research and practical effort goes into sustainable crop management systems, crop rotation, preserving soil quality and maintaining genetic diversity.

Again, Taleb offers no reason why monocultures involving GMOs pose any greater risk than conventional farming does.

He goes on to declare the claimed benefits of GMOs to be red herrings. “Invoking the risk of famine as an alternative to GMOs is a deceitful strategy, no different from urging people to play Russian roulette in order to get out of poverty,” he says.

This is patently absurd. There is no gun. There is no bullet. And reducing the cost of agricultural production, which GMOs do, will certainly help to alleviate world hunger. He says that we should eliminate biofuel subsidies instead, which is true as far as it goes, but that is the real red herring. It’s a false choice. We can do both.

He mentions Golden Rice, which is fortified with vitamin A, and glibly says that vitamin A supplementation can be achieved by other means, which means the “unknown risks” of GMOs are not warranted.

Then he adds: “Given the promotion of ‘golden rice’ by the agribusiness that also promote biofuels, their interest in humanitarian impacts versus profits gained through wider acceptance of GMO technology can be legitimately questioned.”

No, no it can’t be legitimately questioned. Golden Rice was initially a philanthropic initiative by the Rockefeller Foundation. It was developed in subsequent decades by various academic and government institutions. The owners of the patents involved in its development, namely Syngenta, Bayer AG, Monsanto, Orynova and Zeneca Mogen, all provided access to the required technologies free, for humanitarian purposes. Golden Rice is promoted by the International Rice Research Institute, an inter-governmental organisation. Licences to breed and use it are issued upon application by its Golden Rice Humanitarian Board. In this project, it is supported by the Bill and Melinda Gates Foundation. There’s not a hint of agribusiness profit involved. The only potential benefits are for farmers in the developing world and consumers who might otherwise go blind.

Besides, the profit motive is not evidence of evil intent. All farmers are motivated by profit; that is why they feed the world.

Taleb’s bias against Golden Rice in particular, and GMOs in general, is entirely unfounded.

But then, Taleb has long gone off the deep end on such matters. He has expressed public support for other fake science such as homeopathy. These preparations, he claims, are harmless placebos that prevent the over-treatment of marginal patients and reduce the harms that conventional medicine might inflict.

As Cory Doctorow wrote at the time: “Taleb ignores the great body of peer-reviewed, published evidence about the real harms of homeopathy,” namely that people with serious medical conditions such as cancer forgo evidence-based treatment for placebos, and that homeopathic treatments actually lead to more productivity loss and higher medical costs.

Taleb called Doctorow “very stupid” and “dishonest” in response.

Nassim Taleb is a statistician and financial risk analyst. As interesting as his observations about the uncertain risk of large hazards are, his stance on scientific subjects, such as the supposed dangers of GMOs and the benefits of homeopathy, suggests that he should stick to his knitting. We certainly should not apply the dubious precautionary principle on the basis of imagined apocalyptic hazards that exist only in his mind. DM