FINDING a way to live on our planet without destroying or using up its limited resources is essential to humanity's survival. It is one of our toughest challenges, as it requires a combination of science with economics, law and policy. ...

Before moving forward, however, we need policies that stand on firm foundations. One of the key pillars of sustainable policy is the precautionary principle, a concept adopted by the Rio Earth Summit in 1992.

In essence, it states that if you want to do something that might harm the environment, and the science relating to the risk is uncertain, then you must take care.

A historic conference on the precautionary principle at Wingspread, Wisconsin, in 1998, introduced the idea of a "causal link" between activities and harm. The idea was adopted by the European Union in 2000 and has since become pivotal in policy discussions relating to the principle. In May this year, the World Conservation Union (IUCN) proposed guidelines that differentiate between situations where the science relating to a potential threat is uncertain and where it is relatively certain. It defines "relatively certain" as meaning a causal link can be scientifically established.

This might all sound reasonable, but there is a philosophical problem here.

In the 1700s, the philosopher David Hume showed that presenting science this way is fundamentally flawed. A simple example: how do you know that the sun will rise tomorrow? Well, because you have seen it rise on hundreds of mornings; because it has always done so; because day always follows night. But Hume showed that such a conclusion is derived from habit, not logic.

No matter how many events we observe there can always be an exception - and we can never say that because night ends, day must follow.

No one loses sleep worrying whether the sun will rise tomorrow; we strongly expect it will, and we plan our activities accordingly.

But such habits are dangerous in science, and it is precisely through questioning them that our knowledge progresses.

Newton's theory of gravity seemed to have perfect predictive power until Einstein showed it to be flawed. Since then, Einstein's theory has been found wanting, and so it goes on.

As Karl Popper said: "There is no truth, only progress."

The scientific method was designed to take this into account. Instead of trying to establish facts that are definitely true, scientists look for results that disprove their hypotheses.

Seen in this light, science can never deliver what the new interpretation of the precautionary principle promises. ...

The best way forward is to remove the notion of cause and effect from policy. Both Hume and Popper advocated the use of probability theory to ascribe degrees of belief, instead of searching for scientific certainty. ...

Scientists must become more aware of the philosophy underpinning our attempts to understand the world, and make clear to policy-makers and the public what science can and can't do. Our future depends on it.

New Scientist 24 November 2007

Suppose a party stood for election with its political ideas drawn from the prophecies of Nostradamus?

Reactions to this would probably depend on one's level of education, and/or, scepticism.

No doubt, if the policies were presented as leading to a golden age of prosperity, there would be those who would vote for it.

Suppose, however, the party concerned took its ideas from that 19th Century forgery: The Protocols of Zion.

Further suppose that there was already widespread prejudice towards Jewish members of the community.

And finally, suppose that the party concerned planned to rid the community of its Jewish members.

The party, having decided to work within the electoral system after a failed putsch realised it might not be a good idea to be too upfront about this proposal so it does not feature in its electoral manifestos.

It is at this point that the levels of knowledge and scepticism amongst voters will decide whether or not this party prospers.

In the case concerned - the rise of Nazi Germany - the world slump, and a huge unemployment problem, will dictate that the German electorate will look to the Nazis or the Communists because they promise jobs.

The German electorate's inability to see through these blandishments, given the track record of the Weimar governments, was understandable, but catastrophic.

Neoliberal politicians have a similar problem.

In adopting the 10-point Washington Consensus they are adopting a dogma, and one which they knew would be highly contentious had they been upfront about it before setting about implementation.

There was no intent to ask for voters' approval; there was no intent to subject the proposals to the stress-testing of serious debate; no intent to investigate probable unintended consequences.

Like Biblical fundamentalists, or the guy who wants to burn the Koran, the Consensus was treated as a sort of economic Ten Commandments.

They had become a faith: a theory became a dogma.

The case of research into HRT illustrates both the complexity of decision making, and the extent to which such a process can be short-circuited by that corporate alternative: the uber-reporting of flimsy research.

From headlines like these you could get the impression that HRT is a very dangerous drug which should be taken off the market.

The Independent's report certainly confirms this view:

... the world's largest study of hormone replacement therapy (HRT) has shown that it may have caused 1,000 deaths from ovarian cancer between 1991 and 2005.

The new finding strengthens the evidence that HRT poses a serious danger to women. Previous results from the same study have shown that the risk of breast cancer and endometrial cancer (of the lining of the womb) is also increased by the treatment.

Overall, the incidence of these three common cancers are increased by 63 per cent among women currently taking HRT compared with those who have never taken it.

That means 12 extra cases of cancer for every 1,000 women taking HRT over five years.

The risk increases from 19 expected cases among women who had never taken the treatment to 31 among HRT users. ...

The Independent 19 April 2007

This "study" is based on a questionnaire circulated to "almost 950,000 women aged 50 to 64". So, the 'findings' are based on a statistical analysis of the replies:

The latest findings, from a "Million Women Study" and published in the Lancet, focused on 948,576 post-menopausal UK women, representing a quarter of women aged 50 to 64.

About a third of the women were undergoing HRT, while a further fifth had received treatment in the past. All were monitored for up to seven years.

During this time, 2,273 women developed ovarian cancer and 1,591 died.

From this, the researchers, funded by Cancer Research UK, calculated that for every 1,000 women taking HRT, 2.6 developed ovarian cancer over five years - compared with 2.2 per 1,000 in women who did not use HRT.

The Scotsman 19 April 2007

This last sentence seems to put the findings into perspective:

For every 1,000 women taking HRT, 0.26 per cent develop ovarian cancer over five years - compared with 0.22 per cent who did not use HRT.

Without access to sophisticated statistical formulae, I cannot say whether - or to what extent - the difference is statistically significant but it looks improbable:

But Dr John Stevenson, of Women's Health Concern, accused the researchers of frightening women and overstating the risks of HRT. "It is showing a very small increased risk," he said. "They have done a study over a few years, but have extrapolated the figure over 14 years to make it sound important. This is just substituting science with sensationalism."

The Scotsman 19 April 2007

Furthermore, the balancing of risks and benefits seems to have become lost along the way:

Professor Sean Kehoe, spokesman for the charity Wellbeing of Women, said the increased risk of cancer needed to be balanced against the potential effects on quality of life when ceasing HRT. "If a woman does not want to carry this extra risk, then of course, from the information presently available, stopping HRT seemingly reduces this."

The Scotsman 19 April 2007

Finally, did the researchers examine the medical records relating to each individual death - 1,591 women? This would have converted an exercise in low-level statistics into a genuine piece of research.

A new study disputes health scares over Hormone Replacement Therapy, saying the treatment used by millions of post-menopausal women may reduce, rather than increase, the risk of heart disease.

HRT was at the centre of a health scare five years ago when an American study found it could increase the risk of heart attacks, strokes and breast cancer.

Health chiefs then advised HRT should be taken for as short a time as possible, and in Britain it was no longer recommended as a drug to prevent bone loss in women with a family history of osteoporosis.

But a new study just published in the Journal of the American Medical Association found no increased risk of heart attack for women in their 50s who were taking HRT.

The Women's Health Initiative Study discovered that any additional risks may apply only to older women.

Women in their 60s and 70s still experiencing the symptoms of the menopause, such as hot flushes and night sweats, were at an increased risk of heart attacks and strokes even if they were not taking HRT.

The study concludes: "Women who initiated hormone therapy closer to menopause tended to have reduced coronary heart disease risk compared with the increase in coronary heart disease risk among women more distant from menopause."

However, it said the trend "did not meet our criterion for statistical significance".

HRT expert Dr John Stevenson, from London's Royal Brompton Hospital, speaking to the British Menopause Society, said in reports that the findings were a "U-turn of dramatic proportions".

He said: "These conclusions are at complete variance with the widely-publicised 2002 results on which our guidance on prescribing is based. We are astonished that a study which made such a claim for the dangers of HRT is now showing just the opposite."

Press Association Ltd 2007 The Guardian, 09 April 2007