Letters archive

Asking how QM 'really' works reflects a need for a classical deterministic reformulation Patricia Schwarz doesn't understand why people can't just accept quantum mechanics and stop asking "what is real?" ( 19 May, p 44 )

Alex Pearlman says that the chance of a "mini-brain" grown in a lab being sentient in a human way is slim ( 5 May, p 26 ). But how can anyone know that? I am sentient and I can tell you that I am so because my brain is connected to devices that enable it …

You say that "along with other land plants, trees supply around half of the oxygen entering our atmosphere" ( 12 May, p 3 ). That seems to suggest that trees yield a useful net gain in oxygen and a significant net deduction from carbon dioxide. But when they rot or are burned, they consume oxygen …

You report research finding that grassland plants that have the "C3" carbon fixation pathway generally produced less biomass under higher concentrations of carbon dioxide ( 28 April, p 15 ). This does not necessarily mean that the world's plants will produce less biomass with higher CO 2 , even if most plants are C3. Not …

I have been involved in cannabis research for about 20 years and I enjoyed Stephanie Pain's description of William Brooke O'Shaughnessy's work on it ( 5 May, p 42 ). She concludes: "We are now in a new phase of investigation with a push to develop synthetic cannabis-like drugs." I disagree. All the current medical …

Jessica Hamzelou reports a correlation between neuronal size and IQ scores ( 5 May, p 6 ). But, whatever intelligence is, do IQ scores measure it reliably? The format of most IQ tests favours easily measurable qualities such as speed, fine motor skills and the ability to give accurate spoken answers to factual questions. They …

I was interested to read about training quolls to avoid cane toads in order to rerelease them on the Australian mainland ( 5 May, p 10 ). I did wonder, however, what happens when the first generation to be released produce young. Presumably they would need to be trained in turn? You also report Jonathan …

So we have seen a signature of memories in gene activity changes, and it may be possible to create a one-off treatment that would shift a memory's genetic signature from negative to positive ( 14 April, p 6 ). While this is intriguing and the research begs for further examination, I can't help noting that …

Kate Stafford says that bowhead whales can produce two different sounds at once, and "we don't know how they do that" ( 14 April, p 20 ). I wonder whether the whales may be using techniques similar to those used by human throat-singers from Mongolia, Tibet and elsewhere. These singers amplify selected overtones – harmonics …

• Down the back of the sofa: gold worth $22.2 billion was reported to be wasted in 2016 by scrapping all kinds of electronic goods ( 14 April, p 20 ). • Kiersten Dobson is at the University of Western Ontario in London, Canada (Feedback, 12 May ).