Remnants of civilisation
After reading your cover article on Earth without people I again found myself wondering, as I have for many years, whether we really are the first inhabitants of this planet that have had the intelligence to develop a civilisation (14 October, p 36). Apart from temporary colonisation by extraterrestrials (if they exist and could travel between the stars), the only real candidate has always seemed to me to be an intelligent, social, bipedal dinosaur. In an earlier letter I speculated on this (2 July 2005, p 23).
If such a species existed, and if they reached our level of development before they became extinct, it is possible that they had become a spacefaring species, and the easiest way to find evidence of them would be the remains of their space probes on the moon. After at least 65 million years of extinction there would be very few artifacts that survived on Earth, although there might be a few that did. While there is no evidence of such a species, the possibility should not be dismissed out of hand.
Bob Holmes points out that around 100 years’ worth of radio waves are proceeding forever into the universe, showing that we once inhabited Planet Earth. So in 100 years’ time, an intelligent life form with an extremely powerful telescope living, say, 110 light years away would be able to observe the final 10 years of mankind’s habitation of the planet.
The past history of Planet Earth will live forever, or at least until light from it reaches the edge of the universe, if there is an edge.
Seaview, Isle of Wight, UK
Statin statistics
Coincidentally, your article on statins arrived in the same mail delivery as my copy of the Australian Adverse Drug Reactions Bulletin (), which reported that the risk of depression from statins is about 1.4 per cent (7 October, p 46). You commented on the difficulty in determining the true benefit of these drugs, given the long time frames over which they are intended to be taken. We should all remember that similar time delays may well apply to discovering the true risks of statins.
From Richard Paterson
As James Kingsland wrote in his article on statins, “blocking of HMG CoA reductase inhibits the production of many other molecules beside cholesterol”.
Statins also block the synthesis of coenzyme Q10. In a 30-day study using atorvastatin blood levels of CoQ10 were halved (Archives of Neurology, vol 61, p 889). This block was neither mentioned in Kingsland’s article nor considered by the Clinical Trials Service Unit (CTSU) 鈥� whose report is at 鈥� although three other antioxidants were included in the trial. CoQ10, an antioxidant, is a key component of the oxygen-driven electron transport system in mitochondria, and this system plays a large part in ATP (adenosine triphosphate) synthesis in all our cells except red blood cells.
ATP is the crucial energy source of heart and brain and its loss is ultimately responsible for deaths following myocardial infarction or ischaemic stroke.
The potential for a fall in CoQ10 was recognised long before these reports. A major drug company was granted a patent for combined CoQ10/statin therapy in 1990 鈥� see US Patent 4933165 at . One can only speculate as to the reason why this was never taken up.
The reported side effects of statins in muscle and cognitive function could be the result of blocking CoQ10 synthesis.
Finally, the CTSU studied people who already had a substantial risk of death within five years. As your article said, the meta-analysis cranked out significant positive results, but there was no dramatic effect on outcome, even in these patients, at the doses which have to be used to minimise side effects.
So prescribing statins for almost everyone 鈥� or putting them in the tap water, as one madcap enthusiast in the UK suggests 鈥� could benefit only those who profit from selling them. If “you bet your life on” taking statins, you should insist on a coenzyme Q10 supplement. As the article suggests, there are alternatives such as a healthy lifestyle, boosting vitamin D and perhaps 鈥� for those whose can take it 鈥� low-dose aspirin.
Falmouth, Cornwall, UK
Near Death Experiences
Your article on near death experiences (NDEs) focuses on Kevin Nelson’s theory and pays attention only to a materialistic, or purely biological, explanation of near death experiences (14 October, p 48).
Douglas Fox quotes a particular story in which “Joe… was plunged into darkness, then came a bright light, a field of flowers…” You would not expect to find that experience in the studies by Olaf Blanke or others who induce NDEs artificially and try to explain the subjects’ experiences. Conversely, experiences like the life preview, the life review, meeting deceased relatives, verifiable observations during a “real” out-of-body experience and the commonly-reported life-transforming effects of an NDE will never be reported from these simulated NDEs.
Nelson recruited his NDE subjects from the internet, suggesting the possibility that they were untypical. He selected a control group from doctors and nurses at his own hospital. He did not examine whether subjects had rapid eye movement (REM) intrusion into wakefulness before the NDE. The only conclusion of his study was that REM intrusion was found more frequently in a selected population with NDE experiences in their pasts than in his control group. The observed frequency of REM intrusion could perhaps have been an effect, and not the cause, of the NDE.
The only way to answer the questions about possible explanations about cause and content of an NDE is to design a prospective study 鈥� selecting a group of people in advance to compare those who later have NDEs and those who do not.
From Eric Kvaalen
Theories about the connections between various brain states and near-death experiences have been around at least since the publication of Heaven and Hell by Aldous Huxley in 1956. The most serious problem with the theories is that they don’t explain the many stories of people “seeing” things that actually exist. For example, a man recognises a nurse who had taken out his dentures when he was brought into the emergency room in a coma, and asks her about them. Or a man with no pulse or breathing for around 10 minutes sees himself floating through the air to another city and sees a certain caf茅, and then later in real life he passes through that city for the first time and comes across the exact caf茅.
Such stories are routinely dismissed by sceptics as “anecdotes”, but if we really want to understand the world, we must look at all the evidence.
La Courneuve, France
Kratom chemistry
We were interested to read about kratom (Mitragyna speciosa) in your article about “legal highs” (30 September, p 40). We did considerable research into its chemistry in the 1960s and 70s with colleagues in the pharmacognosy laboratories at what was then Chelsea College.
The leaves of the tree are chewed, or sometimes smoked, by labourers in Malaysia and Thailand as a stimulant to help them carry heavy loads for long distances over many hours. We found that the main alkaloid, of several present, was a mild analgesic. Since your writer Gaia Vince made a tea it is not surprising that she did not obtain much effect 鈥� it is unlikely that water would extract the same constituents as those obtained by chewing the leaves.
The labourers suffered ill effects, sooner or later. This must surely raise concerns about the unsupervised use of the leaves. Much investigation is needed of kratom’s constituents other than alkaloids and of the biochemistry and pharmacology of the compounds. Funding for such vital research on natural products is unfortunately scarce in the UK, leaving colleagues in other parts of the world, notably east Asia, to take the rich pickings available.
Killing humanely
In his article about the treatment of animals destined to be eaten, Peter Singer mentions Temple Grandin, a designer of livestock handling facilities, saying “poultry plants should install controlled-atmosphere stunning: using carbon dioxide or inert gases” (7 October, p 22). Surely not! The systems that control breathing act by regulating the concentration of carbon dioxide in the blood. Expose an animal to excessive carbon dioxide and it will experience an acute sensation of suffocation.
The most humane way of killing, if you must kill, is to use an oxygen-free atmosphere 鈥� for example, one containing only nitrogen.
No to patent blether
It is not surprising that Barry Treves feels the need to support the patent system upon which he and other members of the Chartered Institute of Patent Attorneys depend (30 September, p 26). He is well placed, however, to know that the patent system does not work as he suggests. Innovation would be encouraged by the system that Treves describes, but that is not the patent system.
He claims that many drugs were produced only as a direct result of an “effective patent system”. Under the 1983 US Orphan Drug Act, once a product had been approved for sale by the Food and Drug Administration, no licence for a competing product would be issued for seven years 鈥� it granted an actual monopoly. This resulted in a 12-fold increase in innovation.
The existing patent system has failed to accomplish anything like this. Under it, any patent can be challenged for its validity at any time, irrespective of the Patent Office examination. Such challenges usually coincide with a strong claim of infringement. They take up many years and incur considerable expense that is often beyond innovators’ pockets.
Perhaps Treves could explain why the profession that he represents is allowed to challenge patents from every conceivable angle when defending a wealthy client from infringement claims, knowing this is intended to deprive the innovator?
Conscious fallacy
The article on confabulation repeats a logical fallacy (7 October, p 32). “The idea that we have conscious free will may be an illusion,” writes Helen Phillips, because a 1985 experiment “suggested that a signal to move a finger appears in the brain several hundred milliseconds before someone consciously decides to move that finger”.
This is silly. The process of making a “conscious decision” to act is obviously not a single event. Factors for and against action must be weighed up, inhibitions must be overcome, environmental constraints must be checked, the muscular signals must be planned so that the action is properly coordinated, and so forth. That fact that somewhere along this complex pathway a signal can be measured indicating movement of a finger is imminent is quite unsurprising. The fallacy lies in inferring that the sensation of “conscious decision” that appears later on is thus illusory or “faked”.
We sense all things in a delayed fashion. Our conscious recognition of a flash of light, for example, occurs well after the light actually flashes. Why should the sensation of our own consciousness be any different?
And if we have no free will, then why even bother producing the fake sensation of consciousness after the fact? If we, the conscious entity, could not exert any free will over what our body will do in the future, then our body would presumably conserve energy by simply turning out the lights.
Statin statistics
As a medical general practitioner I am receiving more and more stringent guidelines on prescribing statins based on nothing but drug company literature (7 October, p 46). The cost of lipid-regulating drugs in England was 拢600 million for the past year, or 8 per cent of the total primary care drug spend.
We physicians are advised to “do no harm”. Spending vast amounts on medication with side effects that are under-reported, and with the flimsiest evidence of benefit, amounts to harm.
A summary of the evidence on statin use by leading epidemiologists in Germany, published in the drugs bulletin Arznei-telegramm in June 2004, concluded that no life expectancy increase has been demonstrated through the use of statins in primary prevention; women and people over 70 do not appear to benefit from statins for primary prevention; and the latter may be harmed by an increased cancer risk. The authors of the study recommend that statins should not be prescribed to such people.
From Brian Horton
Those promoting statins for all seem to be unaware of the many studies of cholesterol-lowering diets that show the decrease in deaths from cardiovascular disease partially offset by increases in murder and suicide. This is believed to occur because cholesterol has an essential role in brain function: when those with normal cholesterol levels have it lowered by these diets, they become depressed and aggressive.
As expected, the list of side effects of statins includes “extreme irritability, aggression, suicidal impulses”. Since the reduction in death rate is only 25 per 1000, there is clearly a case for including the patients’ quality of life in the overall analysis.
West Launceston, Tasmania, Australia
Whose climate history?
In his letter on climate change, Rod Elliot alludes to the early medieval warm period, then says “we know that humans’ output of greenhouse gases during the medieval period was negligible” (7 October, p 25). While life in parts of western Europe during this period may have been backward and bloody, much of the rest of the world was experiencing an age of unprecedented prosperity.
In the years 800 to 1100 agriculture was spreading fast through the Americas and Africa. The Arab caliphates had reached their high point, with probably half a million people in both Baghdad and Cordoba. Byzantium was still a major power. The Slavic state based in Kiev was growing rapidly.
Asia was booming, turning forest into methane-belching rice paddies. India had enjoyed several centuries of relative peace. Strong unified states had emerged in Japan, Korea and much of south-east Asia. Giant monuments were built in Java and at Ankgor. Madagascar and New Zealand were first settled. Then there was the Tang dynasty in China, the superpower of the time and the first empire to exploit fossil fuels on an industrial scale.
Climate challenge
It may come as a surprise to New 杏吧原创 that some people quite legitimately hold different views on climate change science than your own rigid dogmatism allows (30 September, p 5). The Scientific Alliance exists to promote rational debate in areas of genuine uncertainty. We do not “lecture” people, but present our own interpretations of evidence and ask others to look at them open-mindedly. Neither do we indulge in “politically and commercially motivated abuse of science”, and we are certainly not the ones doing the bullying.
Science is not democratic: the fact that the majority of the scientific establishment subscribes to a particular view does not automatically make it right. Evidence is evidence, and is open to differing interpretation. I challenge New 杏吧原创 to return to scientific principles.
From Anthony Trewavas, University of Edinburgh
I am both a Fellow of the Royal Society and a member of the Scientific Alliance Advisory Forum and I was unable to recognise any of your apparent assertions about the latter organisation. What the Scientific Alliance opposes is the current panic generated among sections of the media and some politicians that has led to the shambles of current energy policy and engendered the simplistic view that destroying the countryside with wind turbines will somehow stop climate change.
If all fossil fuel power stations worldwide were switched off tomorrow, global temperatures would continue to rise for another 50 years. What is desperately needed are calm, balanced and thought-through policies incorporating adaptation, and recognition that those can only be achieved if economic capability is not damaged.
Edinburgh, UK
Nothing besides remains
How sure can we be that, had an advanced civilisation existed some time ago, we could detect the fact now (12 October, p 36)? Bob Holmes suggests that, if “some time” is more than about 100,000 years, there would be few obvious traces. After 10 million years there really wouldn’t be much left of any civilisation.
I would not subscribe to a theory that said, say, some species of dinosaur evolved a large brain, developed a civilisation, gradually polluted more and more of the atmosphere, violently upset the geology of India causing huge volcanic outpourings and finally lost control of a huge nuclear reactor in Mexico, leading to an enormous explosion that deposited a layer of unusual isotopes across the face of the Earth, while wiping out the civilisation along with a fair proportion of the species that then existed… but can we be certain?
From Lucian McLellan
Your article overlooked the fact that there would still be evidence of human civilisation even millions of years into the future.
The atmosphere of Mars, for example, is so thin that the handful of craft we have put there would probably not be eroded beyond recognition before dust storms bury them, to be dug up geological ages later by alien archaeologists who, I fervently hope, would get to see Beagle 2 finally open and attempt to test its rescuers for signs of life.
The last relics of our vision and our vanity will be the two Voyager spacecraft, which have even now begun their journey beyond the solar system. The track of each around the gravity wells of our neighbourhood stars may end in destruction on a planet or in a sun, but each could also possibly be swung out of our galaxy, carrying a plaque depicting humans, and the names of some committee or other, until a supposed end of the universe.
Bristol, UK
From Jonathan Seagrave
Bob Holmes rightly suggests we should show more humility towards our planet. In a few tens of millions of years, erosion will have scoured land surfaces clean of all human traces. Only faint traces of planetary abuse would survive in the ground, such as radioactivity and signs of climate change, in what may be termed the “primate extinction” layer.
What a visiting archaeologist might be able to easily detect would be the pressure hulls of sunken submarines. Around a thousand are distributed widely across the oceans. Some will fill with mud and be buried at modest depth in stable locations. Their size and distinctive shape should betray their origin to a sophisticated scanning system. Nuclear wrecks would speak their presence even more clearly.
Bristol, UK