Letters archive

Emma Young tells us (21 February, p 34) that "the assumption that poor sleep was a symptom rather than a cause of mental illness was so strong that nobody questioned it". The assumption may have been widespread, but it did not go entirely unquestioned. On page 21 of their book Cognitive-Behavioral Therapy of Schizophrenia , …

A. C. Grayling highlighted the need for simple explanations of complex modern-day issues to capture public imagination, and motivate people towards change (14 February, p 25) . In relation to the "bathtub effect" analogy for carbon emissions and fossil fuels, I have always imagined the Earth's fossil fuel reserves to be more of a "sink" …

I don't understand what's so ineffably profound about DNA (21 February, p 22) . Hideously complex yes, even unnecessarily so, like most other products of biological evolution. But fundamentally DNA is only the blueprint part of a self-replicating machine. John von Neumann worked out the mathematical theory of those in the 1940s.

I didn't notice hordes of physicists in a frothing rage when the line "Why Einstein was wrong about relativity" appeared on your cover (1 November, 2008), promoting the feature on page 28 of that issue. Suggest, however, that "Darwin was wrong" about something (24 January, p 34) and cries of "Shame!" and "Irresponsible!" are heard …

Sharon Oosthoek says that around 25 million mice a year are used in labs worldwide (24 January, p 54) . Others have estimated the number of mice consumed as being between 100 million each year in US labs and 500 million (reported by the US Animal and Plant Health Inspection Service in 2000). The fact …

Lawrence Krauss claims that "Darwin's theory of evolution, and the science of genetics which followed, demonstrate that humans and the rest of life on Earth share not just a common heritage, but virtually everything else" (21 February, p 23) . No, we don't. We don't share culture, technology, manners or beliefs. And the poor man's …

I wonder if the perception of size using the ANS (approximate number sense) has any connection with the perception that time passes more quickly the older one gets (24 January, p 40) . When you are 5, a year covers roughly 20 per cent of your memory. By contrast, a year when you are 50 …

Nick Lane's discussion of the warm-blooded nature of mammals reminded me of a fact that has fascinated me for many years (7 February, p 42) . The specific heat capacity of water is at a minimum at about 35 °C – just below the body temperature of mammals. I have always assumed that the mammalian …

Helen Thomson's evaluation of the e-cigarette (14 February, p 33) quotes public health researcher Murray Laugesen as saying that "all pointers so far show the device is safe". Yet the article appears only to consider the risks due to the carcinogens in cigarette smoke, while apparently ignoring the fact that not only cancer but also …

Martin Rees's statement that any aliens we may contact "could trace their origins back to the big bang 13.7 million years ago" (14 February, p 36) is rather like an 18th-century scientist proposing that aliens would know all about phlogiston. The big bang may be the dominant cosmological paradigm of today, but we do not …

Reading the article (7 February, p 30) about the human predisposition to believe in God, I was reminded of Kryten the robot in the TV series Red Dwarf , who was hard-wired to believe that when robots died they went to "silicon heaven". Everyone else knew they just got dismantled. It goes to show that …

I wonder if the search for a "Planet X" (31 January, p 32) should now revert to being one for a Planet IX, since Pluto has been demoted?

• Our review of two books on Islamic science wrongly described Copernicus's solar system as geocentric, rather than heliocentric (21 February, p 46) – a confusion that might have saved Galileo a great deal of trouble. • Rather than China's water consumption being capped by 2020 (21 February, p6) , a 60 per cent drop …

Talk of sleep and behaviour/mood relationships are not new (21 February, p 34) . Sleep and breathing are also not new associations. However, focusing on one causing the other seems to me an oversimplification when there may be a parallel driver for both. It is possible that a genetic predisposition is being triggered or exacerbated …

Averil Macdonald's observation that accountants do not need to attract schoolchildren to their profession is insightful, but several of her premises contrast with my own experience (14 February, p 27) . I have noticed that those who leave the sciences for accountancy generally do so because they became disillusioned with their subject. They feel that …

Martin Gregorie mentions a better method for carbon dioxide capture: convert it to calcium carbonate (14 February, p 26) . Alas, to do so by reacting calcium oxide or quicklime with CO 2 will indeed produce calcium carbonate, but the calcium oxide itself is produced by heating limestone (calcium carbonate), decomposing it and releasing CO …