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Jared Diamond thinks that "traditional" societies sometimes do nasty things, and that state governments are a requisite for peace (12 January, p 26) . His key point is that such societies kill many, be it in "war", infanticide, or the abandonment or murder of the very old. It is of course true that many of …

Joe Kloc misses a possible explanation for the uncanny valley – the feeling of unease when seeing a robot with a strong human likeness (12 January, p 35) . Perhaps because early humans could not easily breed with other hominins, this would have caused an evolutionary pressure to shun those we saw as almost human. …

It will be interesting to see what the Centers for Disease Control and Prevention can come up with in its research into gun violence in the US (26 January, p 6) , but I doubt it will provide any solace to those who think that gun control laws hold the answer to reducing the violence. …

I would like to add my voice to Nobel laureate Harry Kroto's rallying call to ensure the survival of the UK's Royal Institution (26 January, p 27) . Many of us in the science community are well aware of the financial pressures it has been under, which are more than simply a reflection of the …

Several fair points are made in your assessment of the leaked draft of the Intergovernmental Panel on Climate Change's (IPCC) Fifth Assessment Report (22/29 December 2012, p 8) . However, saying that we now have a gloomier picture of the extent to which human-made aerosols reduce global warming is wrong. The draft says the cooling …

A buzzing steering wheel to guide dazzled drivers is unlikely to work (19 January, p 20) . Several years ago, the US military tried a similar device in a pilot's helmet to alert them to danger, but with no success. When a person is stressed, as a dazzled driver is, they will concentrate on their …

In response to Donald A. Sands's letter (19 January, p 31) , while transport of goods is a major contributor to carbon dioxide emissions, it is only a small part of the carbon footprint of an average cup of coffee. According to Mike Berners-Lee's book How Bad are Bananas? , a cup of black coffee …

Carrie Arnold's article on how microbes inside us help shape our evolution emphasised the link between our microbiome and health (12 January, p 30) . However, there is a growing trend in developed countries away from natural childbirth and towards caesarean birth. A baby travelling down the birth canal is exposed to the mother's biota …

I was intrigued that letter writer Amy S. Bouska associates 9 with the colour yellow (19 January, p 30) . For me, 9 is always a cool blue; 5 is yellow; 7 a sinister black; and 4 my favourite pink. I am not a synaesthete, but in kindergarten I learned to associate 1 to 10 …

In your article on "ghostly galaxies", you state that "about 300,000 years after the big bang, the charged hydrogen that filled the universe became neutral and opaque, creating a cosmic fog that blotted out visible light for a billion years" (19 January, p 16) . This is incorrect. When the hydrogen became neutral, it ceased …

While I would not wish to be typecast, I found myself agreeing with Sally Adee that there is a lot more to typography than meets the eye (22/29 December 2012, p 68) . My professional persona manifests itself in Times New Roman (except in emails) whereas jottings for friends and the odd poetic outburst find …

I see that the question has arisen over whether driverless vehicles must perform "merely as well as an average human" (22/29 December 2012, p 34) . Given that, as I am led to understand, most men in the UK think of themselves as far better than average behind the wheel, this might prove a tricky …

Letter writer Martin Ellis seems concerned that a single evil civilisation will take over the universe (12 January, p 28) . But such a civilisation would probably spam the intergalactic internet. So as long as we don't respond to messages saying: "You have inherited a galaxy in the Crap Nebula", we should be safe.

One can only imagine the horror of any all-you-can-eat-restaurant owner when the first customer arrives sporting the new weight-loss device consisting of a through-the-abdomen, surgically fitted stomach pump, recently patented by Aspire Bariatrics ( 12 January, p 19 ).

In your look at digital mapping (19 January, p 44) , Pat Seed, a mapping historian, is quoted as saying: "There aren't universal truths." That sounds like one.