Letters archive

Was the shift to farming really the worst mistake in human history, asks Michael Marshall, concluding that the claim is at best an exaggeration. I would go further, drawing on relevant points made by the researcher Jacob Bronowski( 25 February, p 28 ). You can't civilise on the move. No group of humans has ever …

To argue that a focus on negative emission technologies (NETs) is slowing the fight against climate change is to fall into a common trap. A look at plans drawn up to meet the goals of the Paris Agreement will tell readers that NETs are a baked-in requirement for meeting the 1.5°C pathway( 18 February, p …

On the subject of AIs with theory of mind, a machine will eventually be able to measure things – such as tone of voice, the look of a person's eyes, body position and so on – that we observe when "reading another person's thoughts". This machine will compare these measurements with a database and use …

Surely, every time we find a new source of normal matter, this decreases the amount of dark matter we must hypothesise to explain the behaviour of galaxies( 11 February, p 46 ). One recent example is the discovery that there are far more red dwarfs than we thought. There are other candidates, too. How about …

We know that one form of energy without matter is the photon. Could it follow that gravity without matter is the graviton? Could free gravitons, still exerting a pull, explain the gravitational effects of dark matter?

The idea that vacuum energy at the cores of black holes may be the source of dark energy is awfully reminiscent of steady state theory. Instead of matter continuously being created everywhere in the universe in the latter, it is energy being spontaneously created only in black holes. Not so different( 25 February, p 19 …

One day, I hope to be able to have a "Future Home" of my own and reap the energy-saving benefits. However, houses are built to last, so the vast majority of homes won't be replaced soon. Green technology has to make its way into current homes, with better incentives to retrofit, replacing energy and carbon-intensive …

I passionately support your campaign, together with the i newspaper, to highlight the state of the UK's rivers( Leader, 18 February ). Their current deplorable condition is surely down to the years, if not decades, of chronic underinvestment. For example, the UK government has left the Environment Agency without adequate resources to inspect and monitor …

It was always going to be a big ask to remove sufficient ticks from a semi-forested US area to truly affect Lyme disease rates for people. And yet, the rate of disease among pets did fall significantly. One possible explanation might be the fact that there is a vaccine for pets, but not people( 18 …

The article "Searching for answers" raises interesting questions about the use of AI language models such as ChatGPT in internet search engines( 25 February, p 12 ). With AI also used to generate increasing volumes of internet content, will these systems end up training themselves with their own output? If so, what effect will this …

Your 2000-watt challenge article seems overly pessimistic about the difficulty of cutting energy use. We run our research station, with 12 buildings, on around 14 kilowatt-hours a day, generated by a solar power system with a battery backup. We have lighting, fans, dehumidifiers, power tools, a plethora of lab equipment and a good, basic washing …