Letters archive

Colin Barras correctly concluded that the line between human and non-human tends to be as much philosophical as biological. I am reminded of a subtle behavioural distinction made by physicist Brian Greene when he noted that humans transcend their timeline. This parallels something a philosophy professor told me long ago: humans ask what came before …

When did we become human? When we got language. Everything distinctively human – art, philosophy, technology, religion and so on – is predicated upon it. But its arrival has always been a conundrum for human evolution. First, there is nothing close to our sophisticated language in the animal world. Second, why did we need such …

You report on a proposal to put a frozen backup of Earth's life on the moon. The idea of off-planet reserves for life, albeit not frozen, isn't new. In the 1972 movie Silent Running , forests are kept in giant greenhouses beyond the orbit of Saturn. In any event, any lunar repository could be financed …

I read your article on attempts to detect very early structures in the universe with interest, and was taken by the line "the further back into cosmic history we have looked, the more astounded we have been to see nigh-on fully formed galaxies and supermassive black holes that shouldn't exist because there hasn't been enough …

As a bit of a poet and a bit of a mathematician (and no great shakes at either), I found Peter Rowlett's piece on mathematics and rhyme entertaining, especially the notion of the pi-ku, a haiku variant with syllables based on 3.14 for its three lines, i.e. 3, 1 and 4. Why stop there, when …

I noted that Alex Wilkins left the most important question to the final sentence of his piece on terraforming Mars: should we? Well, of course not. The urge to spread destructive humanity across the cosmos is merely the 21st-century equivalent of European explorers seeking to solve the problems of overexploited Europe by conquering new lands. …

Good to see the hype about screen time deflated and the question of a more sedentary childhood dealt with. A missing factor is restrictive parenting. When I was a child under 10 (early 1950s), I was totally free to roam the streets or the countryside with my friends. Nobody questioned it and you can't have …

Charles Joynson asks whether bringing back the dodo will put the bird on the menu. That isn't very likely, I guess. In 1974, Dutch author Jan Wolkers published his novel De Walgvogel . The title refers to the dodo, which Dutch sailors found on Mauritius and hunted for food. They found the flesh not very …

Modern palaeoanthropology and archaeology can be misleading, I would suggest, and classification of "post-primates" like us and "prehistoric man" is confused ( 3 August, p 32 ). As we devise post-primate species and genus from a scattering of bones and stones, we can't see speech or family structures and dynamics that may be more significant …

A vaccine to stop cows burping methane is very ingenious. But wouldn't it be simpler to farm animals that eat grass and don't burp or fart much methane ? They are called kangaroos ( 10 August, p 16 ).