Letters archive

The prospect that half the world will have myopia by 2050 might be good news for opticians, but is alarming for the rest of us. The fact that encouraging children to spend more time outdoors helps avoid myopia adds to the list of benefits of doing so, reinforcing the need not to shackle them to …

I favour the idea, one of several raised, that exposure to wide open space outdoors is what reduces myopia rates in children, rather than light exposure. Indoors the eye can only look as far as the walls, while outdoors it needs to deal with vistas of hundreds of metres, if not kilometres. Without this, is …

Missing from the item about experiments in which researchers used monkeys to predict US election outcomes was the fact that they strapped them into restraint chairs for hours. Those who defend animal experiments claim that animals are only used for important research questions and when there is no alternative, but what was described is case-in-point …

I was glad to read Kelly and Zack Weinersmith's debunking of Elon Musk's idea of million-strong colonies on Mars. If people insist on living in hostile places either in domes or underground, the world has numerous deserts where they could establish themselves, with any problems concerning temperature, pressure, radiation or communication with the rest of …

Your look at possible botanical craftwork pre-dating the Stone Age mentioned baby slings as a possible example. However, furry mothers don't need them: their babies have something to cling to. When did humans lose their fur? I suspect a lot of other botanical craft came before baby slings ( 9 November, p 32 ).

If anyone still feels that tool use is what turned our animal ancestors into our human ancestors, may I suggest that the dividing line was when the first hominin used a leaf as toilet paper, though I doubt that any evidence survives.

One reader suggested a remedy to the issue of poor fact-checking in popular science books of sticking to the greatest scientist-writers. I contend we should instead turn to the writing of philosophers of the impeccable logic of Bertrand Russell or David Hume, say, who are better able to discern fact from fiction and hyperbole ( …

No one should base ideas of democratic reform on the belief that ancient Athenian "democracy" was an ideal form of government ( 5 October, p 32 ). Athens hardly invented democracy: there were very large polities in Eurasia that show no trace of hierarchy and must have been organised by council and consensus thousands of …

On the idea that insects hold the answer to the dilemma of how best to feed farmed fish, peer-reviewed research I recently coauthored, along with industry statements, casts doubt on the ability of insects to compete economically with fishmeal made from wild-caught fish ( Letters, 16 November ). If insects don't compete with fishmeal, obviously …

Neuroscience progresses through rigorous empirical measures of neural anatomy, circuitry and chemistry; studies of relationships to behaviour; and comparisons among species. Where is there added value from nebulous and simplistic abstractions such as Markov blankets and the free-energy principle( 19 October, p 32 )? These ideas came primarily from philosophy rather than hard science. Their …