Letters archive

In his review of Marcus Wohlsen's book Biopunk (9 April, p 50) , Jonathon Keats claimed that amateur science started in the 1960s, whereas it was actually founded by the "gentleman scientists" who established the entire scientific enterprise when it was considered fashionable to do chemical and electrical experiments at home. Keats also seems ambivalent …

Markings and structures recently found in the Great Pyramid of Giza in Egypt have sparked much speculation (28 May, p 14) . The Egyptians had a formalised style of writing for everything of importance. If it was worth noting, they did it properly. So the first assumption, as your article says, has to be that …

In his observations on the factors influencing bicycle stability, Jerry Cain stated that crashes were "inevitable if we crossed our arms on the handlebars" (Letters, 18 June) . I beg to differ. Riding in Cambridge, UK, as an undergraduate in 1964, I experimented by moving one hand to the other side but close to the …

Your story "Land-grab strategy doesn't hold water" (28 May, p 10) , on the flow of virtual water between countries in the form of food imports, omitted a significant element. As humanity continues to do more with less, we can look forward to technology that will make more efficient use of water resources. This will …

In your feature on "dark earths", the waste from ancient human settlements is credited with the creation of patches of enriched forest soil (4 June, p 42) . I would imagine the largest contributor in that category would be the addition of human excreta. Such waste, incorporating energy, trace elements and minerals gathered from a …

Consider this chain of reasoning. High birth rates produce high oxytocin levels across a population. This hormone has been linked to conservative tribal loyalty and suspicion of outsiders . Low birth rates produce less oxytocin, less tribal loyalty, an openness to non-familiar others and more liberal politics. So are developing countries, with their high-birth rates, …

None of the descriptions of the "many worlds" theory (4 June, p 8) I have seen gives any indication of where the energy to create the infinite number of new universes comes from. The energy of the big bang seems trivial in comparison. Any theory which posits the ongoing creation of the infinite amount of …

As part of her otherwise excellent article on the origins of animal domestication (28 May, p 32) , Pat Shipman wrote that the clincher for the case against domestication being solely for food was: "A domestic animal that is slaughtered for food yields little more meat than a wild one that has been hunted, yet …

Jon Ronson asserts that bipolar disorder is a misdiagnosis in young children (4 June, p 44) . In the US, such diagnosis has caused controversy, but in the UK the problem is the ultra-conservatism of the bulk of the medical profession in failing to identify and treat bipolar, an often lethal illness, until early adulthood. …

Peter Kahn said that we thrive in a natural environment, and that while we can adapt to environments divorced from nature, such as prison, we would not adapt well (4 June, p 32) . The obvious conclusion is that incarceration worsens mental states. This presumably would affect behaviour, with a probable impact on recidivism. Ethicists …

The problem of language in interactive cinema (4 June, p 50 ) reminded me of David Cronenberg's film eXistenZ . Through Jude Law's character's exploration of an immersive virtual world, it does a hilarious job of capturing the awkward, unnatural speech patterns of non-player characters in video games. In order to advance the plot, characters …

• In "The hardest problem" (4 June, p 36) , the number of potential solutions for a 9×9 sudoku grid should have been 6.67 × 10 21 .