Letters archive

Patricia Churchland's account of how our moral behaviour evolved to promote the well-being of human communities appears plausible, but she leaves two major issues out of her reckoning ( 28 September, p 44 ). The first is that these community-building behaviours apply only to our own community or nation. In relation to other communities, we …

The female orgasm may originate in a reflex that makes some female mammals ovulate during intercourse, Clare Wilson reports ( 5 October, p 8 ). In humans, clitoral stimulation is better at eliciting orgasm than penetration. In 2005, Helen O'Connell and her colleagues wrote that "the anatomy of the clitoris has not been stable with …

Fred Pearce asks Johan Rockström whether human population size should be added to his list of "planetary boundaries" ( 14 September, p 39 ). Rockström responds that Earth's life-support systems aren't defined by human activity. Really? The extraordinarily rapid growth of the human population, particularly over the past two centuries, is surely the major influence …

People with severe aphasia – the loss of ability to understand or express speech – may be unimpaired in other thinking abilities, such as chess or spatial navigation, Peter White argues (Letters, 7 September ). And Martin Greenwood suggests that composers use non-verbal thinking, and cites mathematical physicist Roger Penrose's claim that much scientific and …

You report experiments appearing to show that the rate at which speech conveys information is about the same in different languages, despite them having varying densities of information per syllable ( 14 September, p 17 ). This reminded me of evaluating the accessibility of an online product's user interface with a tester who was blind …

Dinah Sage comments on the relative inefficiencies of ovens and microwaves, inviting us to reconsider our use of domestic appliances (Letters, 14 September ). A new approach to services within the home could create opportunities to increase efficiency and reduce carbon dioxide emissions. Typically, a house in a developed country contains a washing machine, a …

Dean Burnett says "far from being a constant annoyance, teenagers may be the reason humanity is as smart and successful as it is" ( 14 September, p 56 ). Can't they be both?

Adam Vaughan says that climate activists should be "embraced, rather than condemned" ( 19 October, p 23 ). I agree that Earth's resources need to be managed with regard to climate change. But Extinction Rebellion activists cannot achieve their aims because these are just not realistic, though they do move the centre of gravity of …

I have campaigned for greater awareness of the social and political implications of climate change for at least three decades. I recall reading environmental writer Rachel Carson as a very young man. I greatly welcome the activities of Extinction Rebellion, and was pleased to read Vaughan's viewpoint . Throughout those decades, there has never been …

Your report on vanishing glaciers in the European Alps is alarming, but there is worse news ( 21 September, p 8 ). Glaciers in the Hindu Kush and Himalayas are melting at a similar rate to those of the Alps. Most large rivers in Asia – the Indus, Ganges, Brahmaputra, Mekong, Yangtze and Yellow – …