Physics plea
You accurately report the recent NASA Senior Review evaluation for Gravity Probe B (online news, 20 May), but not the true complexities of the situation. There are two distinct issues.
First, the actual progress of the GP-B data analysis; and second, the long standing lack of a clear “home” for fundamental physics missions within NASA.
Progress on data analysis is best reflected in a report from another NASA review committee, the GP-B Science Advisory Committee (SAC), chaired by Clifford Will. Its most recent report (November 2007) states “The SAC was impressed with the truly extraordinary progress that has been made in data analysis since SAC-16 [in March 2007]… and we now agree that GP-B is on an accelerating path toward reaching good science results.”
Why then, the difficulty? When we approached NASA for completion funding, the only avenue open was the Senior Review for astrophysics missions. It is no criticism of the reviewers to say that GP-B, as a physics experiment rather than an observatory, was quite unlike the rest of the 10 missions under review 鈥� and almost impossible to fit within a common intellectual framework.
The question of a home for fundamental physics missions at NASA has been raised many times, including a 1999 NASA Advisory Council recommendation that NASA create a Division of Fundamental Physics. Regrettably, this has not yet been done and several missions besides GP-B have suffered as a result. If such a division existed, we believe the agency’s support for the proper completion of GP-B would be strong.
Meanwhile, GP-B continues, and will drive to the very best possible result within the resources available.
Steps to disarmament
I was very interested by commentary by Lawrence Krauss on the statement by 95 scientists outlining a series of unilateral steps that the US could take to reduce the global threat of nuclear weapons (10 May, p 54). I fully agree with the steps outlined, but I think there are further steps that should be taken.
The situation, as I see it, is that the US and Russia are “building down” their nuclear arsenals towards a level of “minimal deterrence” consisting of up to 1500 nuclear warheads each. There is no prospect that the nuclear weapon states will abandon their weapons completely, in the present state of the world: it would be seen as gambling with their national security.
They will only be able to disarm entirely when the system of international law and governance has strengthened sufficiently to guarantee their security without such weapons.
Thus nuclear weapon states have made a promise they cannot keep in Article VI of the (NPT). They promised “negotiations in good faith” on nuclear disarmament and even expressed a desire for “general and complete disarmament”. The non-nuclear weapon states are entitled to charge that they have not fulfilled their side of the bargain, and the NPT is teetering on the brink of breakdown.
The NPT needs to be reinforced or supplemented by a new agreement, in which the US should lead the way. Besides the points made by the group of 95, it should reflect a new and realistic bargain, satisfactory to both nuclear and non-nuclear states.
The preamble should recognise some basic principles:
The terms of the treaty should then include:
I believe that such a bargain would be satisfactory to all parties, with no one feeling threatened by the remaining weapons, and yet the nuclear weapon states have not promised more than they can perform.
Pain
The debate about the legal time limit on abortion is not, or should not be, about the instances of fetuses surviving premature birth before 24 weeks (17 May, p 6). It should concern the likelihood that fetuses suffer pain after 20 weeks of age.
The editor writes:
鈥� Most neurologists who study the fetal brain conclude that fetuses can’t feel pain as late as 29 weeks: before that, the neural architecture to be able to feel pain simply isn’t there.
Vote often
Phil Stracchino objects to instant run-off voting (preferential voting) on the grounds that in some cases a candidate who is acceptable to most voters will be eliminated by a low score of first preferences (3 May, p 20). The same would apply to first-past-the-post voting, which would give a result at least as bad and possibly worse. An alternative was suggested by Peter Gill Dishart (Web letters, 10 May) in which each voter has one positive and one negative vote, to eliminate undesirable candidates. However, preferential voting can achieve the same objective with a modified scoring system.
Some of my acquaintances fill in their ballot paper by putting the highest number (worst position) against the candidate they dislike the most, then the next highest number against their next most disliked candidate. Finally they end with 1 against the candidate they dislike (or distrust) the least.
This suggests an alternative method of scoring votes. Instead of first eliminating the candidate with fewest first preferences, we first eliminate the one with most last preferences. Then we move up the remaining candidates and repeat the process until we have a candidate who is disliked by the least number of voters.
As in Stracchino’s example, this would probably be an intermediate candidate who is satisfactory to most voters and is least likely to be extreme in any direction. This method might be ideal for a presidential election for those countries that prefer a president who does not strongly favour either side.
Incidentally, an advantage of preferential voting that was not mentioned in the original article (12 April, p 30) occurs when it is necessary to elect several candidates. Exactly the same instructions can be given to voters as in a single candidate election. Australia has some single-member and some multi-member elections (for lower and upper houses) and voters can handle either system without changing their method of voting. First-past-the-post methods fail horribly with multi-member elections.
Let's make a deity
I very much enjoyed Stuart Kauffman’s article and sympathised with his expression of a need to “build a sense of the sacred that encompasses all life and the planet itself” (10 May, p 52). He describes his project as “a reinvention of ‘God’ “, but his ideas already have a name: pantheism.
From Steve Welch
While strongly agreeing with Stuart Kauffman on the importance of combining both Einstein and Shakespeare in our world view, and that nature, by itself, commands our unbridled awe, I believe his substitution of the word “God” for nature is wrong-headed. It brings with it a huge baggage of mysticism, supernaturalism, deliberately convoluted thinking and imprecise definitions. Worse, it seems his only reason for doing so is one of appeasement. Sing of the splendour and creativity of the universe by all 鈥� and every 鈥� means, but let’s persuade without losing our reason.
Folkestone, Kent, UK
Cosmetic advertising
Had I been able to comment on Richard Weller’s article on the classification of cosmetics (3 May, p 18) before it was published, I may have been able to forestall some misunderstandings.
It is true that cosmetics companies employ extremely competent scientists who perform high-quality research. Much of that research is published in peer-reviewed scientific journals but, as with medicines, when it comes to studies on finished products, journal editors are reluctant to provide what they see as scientific endorsement for a commercial product 鈥� in other words, free advertising. Of course, companies would love to have their studies published thus, but it is rare.
Studies are nevertheless carried out. Legislation, in the European Cosmetics Directive and the UK Trade Descriptions Act, requires that claims are capable of substantiation. In the UK, claims are further scrutinised by , the body that clears all advertisements before broadcast, and the , which covers print.
So, in spite of the implication in the article, claims made for cosmetic products must be truthful, legal, decent and honest, and this is ensured by a strict framework of regulations and guidelines. High-quality research underpins these claims.
Compliance with a requirement to substantiate claims of efficacy does not lead to the product being considered a medicine. The question of whether a product is to be considered a cosmetic or a medicine is far more complex than simply “if it works, it mustbe a medicine”. I hope I have shown that cosmetic products, too, must work as claimed, but the distinction between a cosmetic and a medicine is more fundamental than just efficacy.
Plague on your pox
A few years ago (24 November 2001, p 34) you published an article about research by Sue Scott and Christopher Duncan which theorised that the Black Death was not, as has been believed for the past hundred years or so, bubonic plague.
I have since found considerable information on the subject, particularly in the work of Samuel K. Cohn, who was independently doing the same sort of research at the same time.
That the Black Death was bubonic plague was an assumption made by Alexandre Yersin, who in 1894 discovered the bubonic plague bacillus and brilliantly elucidated the rat-flea-human epidemiology of the disease. He was not, however, a historian. Descriptions of the symptoms and progress of the Black Death were entirely consistent for over 300 years and have almost no similarities with modern medical accounts of bubonic plague, apart from the occurrence of buboes (swollen lymph nodes), which are found in at least a dozen other not-uncommon diseases.
I have little doubt that the Black Death was a viral haemorrhagic fever of the Ebola type, far more contagious and deadly than bubonic plague.
It is disappointing that you can publish an article such as “Welcome to Fort Plague” (19 April, p 44), which perpetrates the myth that the Black Death was a bubonic plague, without at least referring to the earlier piece.
Whale you were out
Could the rise in numbers of inedible whales in a declining population (10 May, p 41) be a predictable survival strategy?
It would be interesting to discover whether “stinky whale” syndrome is an environmental response or a hereditary trait. That might be an opportunity for a genuinely useful piece of scientific whaling.
In the bag
Feedback is puzzled by why anyone would want a duffel bag waterproof to a depth of 300 feet (3 May). It would be of immense use for holding exactly the items that Feedback suggests 鈥� the box of matches, sandwiches and change of underwear 鈥� for a cave-diver, who might reach an air-filled passage, and even need to camp, at an underground point highly inaccessible from their starting position. This inaccessibility is very much the point of the endeavour.
All over in a flash
What’s really scary is if a “flash gun” made up of nothing but LEDs, some electronics and a battery 鈥� something that looks like a torch 鈥� can live up to the claims that it can “knock people flat” (10 May, p 38).
Five minutes after it comes onto the market someone will figure out how it works, and everyone will know how to make one.
Every criminal will have one to stop police arresting them. Every kid will have one for “self defence”. Imagine what pranksters will do with it.
What stops a lot of wars is that the leaders of democracies know that they’ll have to justify the body bags containing the sons and daughters of voters coming home. So the US military is developing remote-controlled robot weapons and soldiers to make war politically easier.
What stops a lot of crime is that it requires violence. Now the US government is backing a weapon that disables people without using violence 鈥� and so will make crime easier.
May the Lord protect us from idiots.
From Adrian Bowyer,
In tales of derring-do the grizzled old sergeant selflessly throws himself on the grenade, neutralising the blast and saving his platoon by sacrificing himself.
It was almost as selfless of the Department of Homeland Security to give $600,000 to the Nanohmics company to develop a non-lethal, incapacitating, LED flash grenade.
This can obviously be neutralised by the rather less extreme stratagem of throwing one’s coat over it. One even gets one’s coat back.
Bath, UK
The editor writes:
鈥� Other measures 鈥� wearing tinted glasses, say, turning away from the light or simply closing your eyes 鈥� could prove just as effective. However, the weapons developers argue that these very actions could give security services a momentary advantage.
Carbon tax where?
Harro Drexler takes it as read that a carbon tax should be applied at the point where the fossil fuels are extracted (17 May, p 22). This is far from clear.
What if the fuel is not used to produce carbon dioxide but, say, plastics which may be recycled indefinitely? What about non-fossil fuels? Wooden furniture may be burned when no longer wanted, so should all wood products incur the tax?
It does seem more natural to take the release of CO2 into the environment as the taxable event, though I admit carbon capture produces a grey area.
There are also international considerations. It would be essential that the country that collects the tax is the one that deducts correspondingly from its emissions allowance under international treaty.
From Phil Nicholson
I agree entirely with Harro Drexler: instead of dodgy carbon trading, emissions should be taxed at source.
This is such a simple, obvious and effective solution, working on the existing principle that “the polluter must pay”, that it makes you wonder whether carbon trading was designed to get around, rather than to solve, the problem.
Calculating the necessary tax is not rocket science, and anyway most of the hard work has already been done. The UK Treasury’s estimates that the cost to the environment when everything is considered 鈥� crop failure, floods, fires, premature death due to heat, and so on 鈥� comes to around 鈧�85 per tonne of carbon dioxide emitted.
So coal-fired power stations should be charged 鈧�0.11 or around 8 pence per kilowatt-hour of electricity. If emissions during opencast extraction of coal were also taken into account the tax rate would be greater. The claim that coal power is cheap is only valid when ignoring the environment.
Glasgow, UK
So what is science?
Robert Matthews’s examination of Karl Popper’s criterion that scientific hypotheses are defined by their falsifiability, and of alternatives like Bayesian probability, provides an illuminating view for modern physics (10 May, p 44). Particularly at very large and very small scales, physics sometimes lacks the comfortingly straightforward Newtonian cause and effect that is so easily verified experimentally.
Often, vast numbers of observations and sophisticated statistical analysis, more at home in the biological sciences, are required. Falsifiability does not sit so comfortably within such complex analyses.
A more speculative approach is encouraged by Bayesian analysis, but there are dangers. Recent descriptions of the universe have meant invoking multidimensional and even multi-universe views, and exotic substances such as dark matter and dark energy. Unfortunately, these concepts sometimes appear to resemble older distractions such as phlogiston, that strange substance chemists invoked to explain weight loss during combustion processes.
Neither Popper nor Bayes can claim to have all the answers. Beyond science, there is also the human aspect. Competition for research positions is extremely fierce, and employment selection criteria may well have more to do with survival of the current paradigm than scientific logic.
From Christoph Bluth
Robert Matthews’s article seems to show that some scientists do not have a proper grasp of the principle of falsifiability. A theory (or a statement) is not falsifiable if it is compatible with all conceivable empirical evidence. 杏吧原创s are confusing “falsifiability in principle” with “falsifiability in practice”. There are many scientific predictions which cannot be tested because we currently lack the means to do so 鈥� but can be tested in principle, and therefore satisfy the criterion of falsifiability. The example that Lawrence Krauss gave Matthews, of Einstein’s prediction that gravitational distortion of light produces a bright ring around a star, was falsifiable in principle.
Much of the confusion in this article has to do with semantics 鈥� the meanings of “science” and “theory”. A more rigorous conceptual analysis shows that falsifiability remains central to any propositions about the “real world”.
Bradford, West Yorkshire, UK
From Miles Rzechowicz
Max Tegmark’s contention that it is “a fallacy” to say the multiverse theory is unfalsifiable, because the theories it is built upon are falsifiable, demonstrates his lack of understanding of the philosophy of falsifiability.
What if we never falsify quantum theory? Does that mean that the multiverse must exist?
Of course not. If quantum mechanics stands, the multiverse may still be a complete fiction, but cannot be proven so because it cannot be falsified. This is part of what makes much of cosmology unscientific.
Hamilton Hill, Western Australia
Carbon to go
I see Ning Zeng is considering burying wood to lock up carbon dioxide (3 May, p 32). I agree with him that we should be growing the wood, but has he not realised that the burying has already been done by nature long ago in the form of coal? Why not simply leave the coal where it is, already buried, and burn the wood instead?
Wherever in the world there is enough rainfall, we could grow trees to be burnt in small electricity-generating plants surrounded by the plantations producing their fuel. Come on somebody, we need you to design modern, farm-sized power stations specifically to burn plantation timber grown on the spot.
Modern technology could build plants needing little manual labour, but it could also be done where labour is cheap, with simple engineering methods and local rural manufacturing and maintenance; just what the world will soon need. The whole cycle would be CO2-neutral and not limited by fluctuations in sunshine or wind.
Here around the port of Albany, Western Australia, something like a third of all farmland has gone over to timber production in the past 15 years, producing wood chips for paper production. This has proved to be more profitable than the meat and wool production that it has displaced. There is no doubt we can grow trees.
Does Ning Zeng really want us to bury wood so that we can continue to dig up coal?
From Peter Marshall
On our farm we bury a tree every day, without the expense of the backhoes and bulldozers suggested by Richard Lovett. We cut “long fodder” (willow, poplar and bamboo) from wood lots and shelter belts and throw it over the fence onto pastures. Goats and sheep come running to strip off nutrient and mineral-rich leaves and bark. Then we distribute the stripped poles around the grazing land, where they act as micro-terraces 鈥� trapping water and reducing soil erosion, wind speed and evaporation.
Over a year or two the protected pasture grows over the wood. It disappears as chunks of carbon into the soil, where it lasts for many years.
The technology is simple enough: sharp saws, billhooks and solar-powered electric fences to protect the coppice blocks from destruction by stock browsing. That fencing also makes a productive foreign-aid gift to goat-browsed countries such as Afghanistan. Without it the task of growing trees must be near impossible.
Braidwood, New South Wales, Australia
For the record
鈥� The map with the article “Vote of no confidence” showed Minnesota with 32 votes in the electoral college that selects a US president (12 April, p 30). It has 10.