Letters archive

In his critique of sustainable economics, Thomas Hogg ignores the fundamental argument in its favour: that unrestrained growth will eventually bankrupt the planet (8 November, p 20) . Instead, he claims that scientists do not realise that zero growth is a feature of recession and therefore, he assumes, inherently bad. He completely misses the point …

Contrary to what your report says, I am satisfied with the latest guidelines on who to screen for testosterone deficiency and how to treat it (1 November, p 8) . I do not think they should go further, especially not until there is more evidence in relation to diabetes. The European Association of Urology guidelines …

Mark Buchanan's discussion of spurious causality (1 November, p 15) reminds me of an observation I repeatedly make when advising on risk analysis: that the attention given to a countermeasure or procedure is often inversely related to its effectiveness, especially when no clear measure of its effectiveness is available. Fairly effective are: orbit predictions, vaccination, …

Your discussion of renewable energy was heavily focused on its large-scale applications (11 October, p 30) . These are an option, but we can think far more progressively and make the change to renewables concurrent with a change towards a decentralised power supply. What happened to the idea of moderately self-sustaining solar-powered homes that receive …

Owen Clarke expressed concern about "peak lithium" and the limits it might place on the production of electric-car batteries (11 October, p 20) . A lithium-ion battery with a capacity of 60 kilowatt-hours would contain about 5 kilograms of lithium, according to www.batteryuniversity.com . The US Bureau of Mines reported in 1990 that the available …

I appreciate your concern that the use of brain scans in evidence could result in wrongful convictions (4 October, p 5) . But a more useful question is: might fMRI scans prevent or overturn some wrongful convictions? In 1998, criminologist David Wilson at the University of Central England cautiously estimated that 2 per cent of …

I am struck once again that scientists researching animal cognition – in this case, thinking backwards and forwards in time – assume that other animals are fundamentally different from us unless proved otherwise (1 November, p 32) . Why is this? We are, after all, part of the same evolutionary continuum. Charles Darwin believed that …

A. C. Grayling muses on why it is so difficult for the brain to understand itself (4 October, p 50) . Is this because it's too marvellous, or because it is not marvellous enough?

• We reported questions over the stability of NASA's Ares I rocket design in winds of 20 kilometres per hour, based on a 26 October Orlando Sentinel report (1 November, p 6) . At a NASA press briefing on 29 October, the agency said that the true figure is 63 kilometres per hour, and that …

Practical considerations will limit most wind turbine projects and installations to the 2.5 to 3-megawatt size range (11 October, p 33) . Component size, fabrication, transportability and erection become increasingly overwhelming and costly as the desired power output rises. The blades of a 5-megawatt turbine will be 90 metres long, and those for a 10-megawatt …

I was excited to read that a computer program had fooled a quarter of the judges into thinking it was human in a 5-minute text-based conversation, thereby winning this year's Loebner prize (online news, 13 October) . This is just under the 30 per cent required to pass their version of the Turing test, which …

You report the high environmental cost of meat (13 September, p 28) . Vast numbers of animals are killed worldwide as pests, or culled on environmental grounds. I admit that the "Multiple McLocust" may not be a marketing dream, and Australia's cane toads are unfortunately toxic, but rabbits are an under-used resource. Before anyone complains …

Valerie Jamieson ignored one significant source of concern about the experiments to be conducted at the Large Hadron Collider (27 September, p 18) , though she did allude to it when referring to "the cultural illiteracy of scientists". I suspect the concern arose not from a public ignorance of physics, but from statements made by …

I am concerned that the prostate-specific antigen (PSA) test is often written off as having little if any value, as you do (25 October, p 31) . Since I owe my life to the test, I believe it does have real value. With both my father and uncle suffering from prostate cancer, we, the next …