The Precautionary Principle:
Safe or Dangerous?


Politicians at all levels are often encouraged to apply the so-called "Precautionary Principle" when considering whether to allow the development of new technologies. The idea for this article arose from controversy about cellphone masts, but it applies equally to other controversial issues, such as bio-engineering (the genetic modification debate). Here is my perhaps equally controversial take on it.

The basis of the "precautionary" principle is that, until a new device or technique has been proved to be "safe" (whatever that means in the context), it ought not to be allowed. Those who advocate it also argue that the burden of proof should lie on those who promote and profit from it.

It is a plausible approach, especially in the light of dreadful tragedies like thalidomide births and, some would say, the dangers of nuclear radiation. But is it really that simple?

There is a fundamental principle of justice - well, British justice, anyway - that the burden of proof lies on the prosecution to prove guilt beyond reasonable doubt. Few, I think, of even the most ardent advocates of the precautionary principle would argue that it would be right to convict and imprison a person unless the accused could prove his innocence: that would quite rightly be regarded as unjust, even if the accusation were of a serious nature, the accused a notorious person and his accusers all persons of unimpeachable character.
The notion underlying this principle of justice, often cited as the cornerstone of the English criminal law, is that it is extremely difficult to prove a negative.

So what's the difference?

Well, firstly, no-one can be accused of a crime unless a crime has actually been committed. The precautionary principle would turn this on its head and require it to be demonstrated that no harm will arise at any time in the future, no matter how distant.
Beyond that, I have to say I cannot see much difference between the precautionary principle and the presumption of guilt and that is why I regard it with little enthusiasm. We accept, as a matter of natural justice, that there is some risk in waiting for a crime to be committed before apprehending a probable criminal. There have been cases of persons "known" to be criminally insane and potentially dangerous committing extremely nasty unprovoked assaults on unsuspecting, innocent citizens. Despite discussion from time to time of the perceived merits of "making the streets safer" by bending the long-established principle of the presumption of innocence in response to particularly awful examples of this kind, almost all of us are prepared to accept the risk from the very few as the price of freedom for the majority from the greater risk of injustice against the innocent at the behest of malevolent accusers.

The criminal law rightly requires a high standard of proof for a conviction, namely that an accused person be proved guilty beyond reasonable doubt. This standard is not absolute, but it has served us well enough for centuries. I hear little clamour for a yet higher standard of proof (say, "beyond any possibility of doubt whatsoever"). The principle here is that we expect to be governed reasonably. Hardly anyone would argue that this is unreasonable: indeed, to do so would be a contradiction in terms.
Yet this is what is implied by the "precautionary" principle: the requirement of the precautionary principle is that the purveyors or promoters of a novel device or technique be required to prove, not merely beyond reasonable doubt, but absolutely, that no harmful effects, no matter how unlikely, can arise from the device or technique. I would argue that such a standard is unreasonable, not only because it is impossible to prove a negative, but also because it is a standard of proof that is beyond unreasonable doubt and ipso facto of itself unreasonable.

Bad news sells more newspapers than good news. Scare stories attract more attention than news of a useful invention. Scare stories run and run; they are easy to write, require little research and even less knowledge; they need no more than fear, uncertainty and doubt to keep them alive and their authors rubbing their hands all the way to the bank. Most of them turn out to be baseless or, at most, greatly exaggerated. It is easy to frighten people, especially with pseudo-scientific mumbo-jumbo that few people know enough science to see through. It is very difficult to reassure, when reassurance depends on an understanding that few have.

My conclusion from all this - on balance of probability - is that the "precautionary principle" is a clever and dangerous con. It turns scare stories into weapons of mass destruction against progress and invention. Adopting the principle as a matter of policy would put any novel technique at the mercy of luddites and scaremongers, sometimes with vested interests; make them secure in the knowledge that they can demand an impossible standard of proof, and thereby deprive the rest of us of the benefits of invention. I think that that is a much worse and more certain risk than accepting the very much smaller one that, once in a while, the scaremongers and doom-merchants might be right.

Does that make sense? Email me if you have a view.

26 September 2004