Letters archive

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 …

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 …

Regarding the video assistant referee (VAR) system in football, how about adding a few rules about its use? For example, the on-field referee could only request VAR if they were really uncertain about a situation, not just to "make sure", and off-pitch officials could only give their opinion if the referee asked them for it …

Daisy Christodoulou's lament for the English Premier League under VAR shows that football administrators in the UK aren't cricket fans. Many major cricket matches have an off-field third umpire who is equipped with scientific monitoring systems, but who doesn't interfere unless one team appeals an on-field decision to them. Each team has a limit of …

We could do away with video reviews in sport if we framed the rules in terms of the officials' perception of events rather than the events themselves. The sport of race walking did just that when photography showed that the foul of "lifting" – losing contact with the ground – happened far more often than …

You report research stating wing feathers originally augmented running in birds. In Tasmania, we have the endemic flightless Tasmanian native hen, or turbo chook. It is fleet of foot and earns its nickname from its supreme ability to rapidly run for cover when chased. The birds can also turn 90 degrees at pace by simply …