The precautionary principle (PP) is often used to justify actions that radically infringe on liberty, but it is an unreliable guide to managing risk, both for society and for individuals. Warren Meyer makes this point forcefully in a recent post entitled “A Unified Theory of Poor Risk Management“. The whole post is worth reading, but PP is the focus of second section. Meyer offers the following definition of the PP from Wikipedia:

“The precautionary principle or precautionary approach to risk management states that if an action or policy has a suspected risk of causing harm to the public or to the environment, in the absence of scientific consensus that the action or policy is not harmful, the burden of proof that it is not harmful falls on those taking an action.”

He goes on to explain several problems with PP, the most important of which is its one-sided emphasis on the risks of an activity while dismissing prospective benefits of any kind. Enough said! That shortcoming immediately disqualifies PP as a guide to action. Rather, it justifies  compulsion to not act, which is usually the desired outcome when PP is invoked. We are told to stop burning fossil fuels because CO2 emissions might lead to catastrophic global warming. Yet burning fossil fuels brings enormous benefits to humanity, including real environmental benefits. We are told to stop the cultivation of GMOs because of perceived risks, yet the potential benefits of GMOs are routinely ignored, such as higher yields, improved nutrition, drought resistance and reduced environmental damage. Meyer asks whether there is an irony in ignoring these potential gains, as it entails an acceptance of certain risks. Forced energy shortages would bring widespread economic decline. Less-developed countries face risks of continuing poverty and malnutrition that could otherwise be mitigated.

The terrifying risks cited by PP adherents are generally not well-founded. For example, climate models based on CO2 forcings have extremely poor track records. And whether such hypothetical warming would be costly or beneficial, on balance, is open to debate. The supposed risks of GMOs are largely based on pseudoscience and ignore a vast body of evidence of their safety. As Meyer says:

“… the principle is inherently anti-progress. The proposition requires that folks who want to introduce new innovations must prove a negative, and it is very hard to prove a negative — how do I prove there are no invisible aliens in my closet who may come out and eat me someday, and how can I possibly get a scientific consensus to this fact? As a result, by merely expressing that one ‘suspects’ a risk (note there is no need listed for proof or justification of this suspicion), any advance may be stopped cold. Had we followed such a principle consistently, we would still all be subsistence farmers, vassals to our feudal lord.”

The PP has obvious appeal to statists and fits comfortably into the philosophy of the regulatory state. But it’s a reasonable conjecture that widespread application of the PP exposes the world to greater natural and economic risks than without the PP. Under laissez-faire capitalism, human action is guided by the rational balancing of benefits against costs and risks, which has brought prosperity everywhere it’s been practiced.