Science can be trusted because it comprises an immense body of interlocking data and interpretation. Where there are loose ends, that is the cutting edge, the current research that keeps working scientists busy. But, as Lewis Wolpert pointed out forcefully in The Unnatural Nature of Science (1992), science is not a more rigorous form of common sense. It is often deeply counter-intuitive. No one thought up the idea of radio because it seemed like a good, practical, commonsensical thing to do and really useful to boot. It is an unlikely phenomenon predicted by the profound mathematical equations of electromagnetism formulated by James Clerk Maxwell in the 1860s. Similarly, atomic energy or the four-base DNA genetic code of all living things.
But when we are talking about matters of life and death or technologies that impinge on our livelihood, science inevitably butts up against our commonsense notions, emotions, beliefs and prejudices. That's where the trouble starts. In the philosopher Massimo Pigliucci's entertaining and valuable guide to sorting the scientific grain from the chaff of pseudoscience, Nonsense on Stilts (University of Chicago Press, £13) he makes a distinction that clarifies some of our current problems. There are two kinds of bone fide science: one is law-based and experimental, cut-and-dried as a crystal chalice or a perfect intertwined double helix of DNA. Then there are historical sciences such as evolution or climate research that employ "the methods of a crime detective".
Although almost every member of the human race has a whodunit mindset and many people follow notorious trials and disaster enquiries with intense attention to detail, this faculty seems to desert them when it comes to science in the public arena. After a welter of admittedly complicated and less-than-definitive data, a few dodgy climate emails seem to have induced a premature verdict in many minds.
More persistent sleuthing is required. We send people to prison, and formerly used to execute them, on the basis of the balance of inference in evidence. Isn't the evidence that will shape our fate worthy of equally stringent attention, and shouldn't there be a presumption of innocence? Those who argue that historical subjects such as evolution and climatology can never be truly scientific ought for consistency's sake to argue against the legal process of assembling a criminal case by the interlocking mesh of evidence.
In science and law, the process is exactly the same: once one clue is obtained, inferences lead to predictions which, if corroborated, convince the respective relevant bodies (jury in law; peers in science) that a correct interpretation of events has been attained. A good example is the hardening case for the extinction of the dinosaurs, along with a high proportion of all species on earth, 65 millions years ago, through a catastrophic meteorite collision.
The strongest pointer is the existence of a strange worldwide iridium-rich stratum in the rocks at a division between the Cretaceous and the Palaeogene periods dated to that time. When the iridium was discovered in 1980, no meteorite impact large enough was known, but ten years later the Chicxulub crater beneath the Yucutan Peninsula in Mexico was identified as the site. On 5 March this year, an international team concluded unequivocally that "the Chicxulub impact triggered the mass extinction."
But, as Pigliucci points out, what happened happened, and can be deduced by the trail it left; what might happen in the future involves contingency, freak occurrences that can tip the path of events onto a different course – "for want of a nail...". We can reconstruct the meteorite event of 65 million years ago but cannot predict the next such strike. We are left with a range of probabilities.
To cut to the chase: global warming is what most of the current fuss is about. In 2001 the Danish academic Bjørn Lomborg wrote a book called The Skeptical Environmentalist, in which he tried to paint a rosy picture of mankind's prospects in all matters environmental. He followed this up in 2007 with Cool It, specifically devoted to climate change.
Lomborg's "Theorem" (his critic Howard Friel's term) boils down to the idea that the world is sufficiently rich and inventive to solve all potential problems of climate change without interfering with economic growth. He cites the facile example of the problem icebergs once posed for transatlantic travel, following the Titanic disaster. Answer: we learnt to fly over them.
This problem could be solved because in a relatively unexploited world there was a new medium to conquer: the air. But the air polluted by carbon dioxide from the half a million people who are flying at any moment is now part of our problem. If we try to solve the problem of aviation fuel (planes can only fly on carbon-based fuel) by growing biomass to replace fossil- with carbon-neutral-fuel, it forces up food prices because really we need all that land to feed us. This is only the first such problem we face of one resource beggaring another.
In The Lomborg Deception (Yale, £18.99) the independent scholar Howard Friel has taken it upon himself to trade clauses with Lomborg in an effort to refute him. Lomborg has already rushed out a rebuttal of Friel on the internet, and Friel has riposted, also online. Behind all these tussles lie the three huge volumes of the 2007 report by the Intergovernmental Panel on Climate Change (IPCC).
There seems almost to be a devilment factor at work in trying to get the facts straight about the big public issues in science. Looking at the IPCC, Lomborg and Friel, all three make mistakes. Despite the fact that around 2000 scientists worked on the IPCC report, the ill-referenced error claiming that the Himalayan glaciers would melt in 2035 still infiltrated the final text: this seems to be a Chinese whisper, stemming from an estimated date of 2350 made in the 1990s. Friel, unfortunately, repeats the claim and berates Lomborg over four pages for it.
One of Lomborg's key points is that, on balance, although global warming will lead to additional deaths from some diseases, especially malaria and respiratory conditions, in the world as a whole more lives will be saved from the alleviation of cardiovascular diseases in winter. Friel claims that Lomborg cites no reputable source, but in fact, as Lomborg point out in his web rebuttal, he does cite a 2006 report in the journal Ecological Economics which suggests that on balance in 2050, 850,000 more lives would be saved than lost. But then, if you look at Cool It, Lomborg claims that 1.4 million lives would be saved, not 850,000, ignoring deaths from other diseases, including a hefty 485,000 from diarrhoea.
Reading Lomborg, one realises that his whole argument rests on the scenario that the effects of global warming (which he does not deny) do not justify the dire economic consequences that would result from drastically cutting carbon dioxide emissions in the very near future. He, like most governments and citizens, wants to see emissions reduced by moving to renewable energy sources. Simply shutting down power stations and ordering cars and lorries off the road without replacements is unthinkable, but this is the straw target Lomborg repeatedly skewers. As Massimo Pigliucci exclaims: "So what's an interested, politically moderate but socially concerned citizen to make of all this"? Who or what can you trust? Pigliucci suggests that you cannot simply rely on the opinions of authority figures. Even Einstein sometimes got it wrong, at first predicting that, despite his equation E = mc2, no power would ever be gained from the atom. In science, as in life, there is no substitute for weighing up the evidence, just as a jury does.
David Goodstein's On Fact and Fraud (Princeton, £15.95) comes as a gentle relief after the relentless clause-by-clause disputation between Friel and Lomborg. Yet, paradoxically, it is actual cases of scientific fraud he is talking about. Goodstein is both a hands-on practitioner of science and for many years the officer at the California Institute of Technology charged with maintaining scientific ethics. A genial guide, he shows that sometimes the deciding line between fact, self-delusion and outright fraud is hard to spot. He gives two examples. One is of a science that seemed to flout all the principles of physics and is almost certainly wrong: the widely reported cold fusion, or harnessing the power of the sun or an H-Bomb in a simple test-tube experiment at room temperature. The other is the counterintuitive principle of superconductivity: electric currents that flow for ever in perpetual motion. This definitely works but no one quite knows why.
In all the recent controversies the phrase "peer review" has been on everyone's lips. Of course, peer review is a vital part of the scientific process but it is not the final guarantor of scientific veracity and probity. The best review of a scientific paper is the work that follows, when researchers try to replicate or build on the findings. Some recent cases of scientific fraud were published in the best peer-reviewed journals. As for one of the greatest discoveries of all time, John Maddox, editor of Nature for 22 years, said: "the Watson and Crick paper was not peer-reviewed by Nature... its correctness is self-evident. No referee working in the field could have kept his mouth shut once he saw the structure."
In the wars of words about science, we could do with more of that kind of straight talking and decisiveness.
Peter Forbes's 'Dazzled and Deceived: Mimicry and Camouflage' is published by Yale
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