No nonsense
Isn’t it time we steered clear of mysticism in mathematics and physics? In his article, Matthew Chalmers says the square root of -1, also known as the imaginary unit i, is a nonsensical concept. This continues the Greek tradition of mixing irrational philosophy with logical developments (25 January, p 32). The imaginary unit is no less real than any other mathematical concept; it just happens to have an unfortunate name, as Chalmers grudgingly admits in his final paragraph.
In physics, use of complex numbers 鈥� which includes i 鈥� allows two-dimensional problems to be expressed in terms of one variable, with huge simplification in the processes that have to be carried out to solve them.
Bridport, Dorset, UK
Eye of beholder
Alison George’s article on the significance and implications of prehistoric cave art to the rise of human intelligence was thought-provoking (23 November 2013, p 36). Also worth mentioning in this context is the work of David Lewis-Williams, who led the Rock Art Research Institute at South Africa’s Witwatersrand University for 20 years.
According to him, the dots, lines and triangles found in El Castillo cave in Spain are representative of images generated automatically by the human visual cortex, known as entoptic forms. One of the many ways these forms are generated is through prolonged exposure to darkness 鈥� in a cave, for example.
Carmarthen, UK
Size is an issue
Why is it only “arguably fairer” to take population size into account when determining a country’s contribution to global warming (18 January, p 12)? Surely it is much more equitable than just taking the absolute figures and relating them to a country’s area regardless of population.
In my street, I produce less waste than my neighbours, who occupy a similar living space. They also use more energy. Are they “worse” polluters than I am? They happen to be families, mostly with children, whereas I am a single person living alone. Is it reasonable to expect them to consume and pollute only as much as me?
London, UK
Tune in my head
Your look at musical hallucinations gave no idea of the perceived volume of the music Sylvia was hearing in her head all day (18 January, p 8). My head has played me music continuously, ever since I heard my first song as a child over 60 years ago. I did find simple repetitive melodies, such as A Windmill in Old Amsterdam, annoying, but managed to change the tune. This internal music is rarely so loud as to block out music I’m playing in my job as a violin teacher.
It can be quite useful for reminding me of an appropriate melody for an upcoming performance. I don’t view this as a hallucination that needs to be “corrected”. However, if the volume were to be consistently loud, it would be a problem.
Whitstable, Kent, UK
Road to destruction
I fear that building more roads in Africa to improve economic prospects will disrupt more than just game reserves (11 January, p 8). Greater access to rural areas allows in illegal hunters, who will extinguish all game near roads.
I have seen this happen within a few years in Zambia, where tracks created in the 1960s to support geological surveys in copper mining areas made it easy to kill animals and transport them to market. Even in relatively animal-free areas of South Africa such tracks have made it possible to remove bushes and trees for fuel.
Barton On Sea, Hampshire, UK
Let's talk about sex
The concern over iatrogenic deaths (25 January, p 5), that is those caused by adverse drug reactions and hospital-acquired infections, for example, needs to be linked to the differences in the safety and effectiveness of medical treatments for women and men. Sex differentiation begins in the embryo and changes affecting exposure, susceptibility, risk and health continue throughout life.
Because historically women have been routinely excluded or under-represented in pre-clinical and clinical studies, and sex differences went unexplored and under-reported, science has more evidence for men than for women. Many occupational epidemiology studies, for instance, have excluded women and minorities, and have commonly generalised species’ responses to drugs and other chemicals without gathering data to consider female and male differences.
There are other examples. In 2009, the journal Pain, provoked by the observation that over 70 per cent of the studies it had published in the previous 10 years had used male animals only, called for a consensus on how to conduct studies of pain that properly account for sex and gender differences.
London, UK
All the rage
It seems to me that technology can only accentuate our tendency to dehumanise others as described by Laura Spinney (18 January, p 39). Take driving. It is hardly surprising that road rage happens when we have at our disposal only the most primitive forms of communication 鈥� blaring horns, flashing headlights and shaking fists. The vehicle masks the human inside, sliding the safety catch on our propensity for dehumanising others.
Then there is warfare delivered remotely 鈥� by drone, long-range artillery or missile. Add to that the dehumanising effects of social networking and you begin to understand, though hardly condone, the behaviour of trolls.
Stockport, UK
Innate behaviour
In his letter, John O’Hara seems surprised that wild turkeys can behave in certain ways without having had contact with adult turkeys (18 January, p 29). We should expect that the vast majority of animal behaviour is genetically inherited.
Relatively little behaviour is learned, except in more intelligent species with longer childhoods. Consider the many species of cuckoo. Raised in the nest of a host species, the chicks may never have any contact with their biological parents. Yet they are able to migrate and return the following year to mate with their own species and repeat the cycle.
They can’t have learned any of this 鈥� it must be inherited. This is also true of many insect and reptile species that never see their parents.
The intergenerational memory transfer Linda Geddes reported (7 December 2013, p 10) is not inherited behaviour in the accepted sense 鈥� it is not common to all mice.
Stirling, Western Australia
The point of religion
Letter writer Dan Hochberg and his co-religionists “find Richard Dawkins so irritating” (25 January, p 31). So do we non-religionists. For all his brilliance in explaining evolution, Dawkins seems to miss the point of religion.
Religion, as a human behaviour, has evolved by natural selection because of the benefits it confers on its practitioners.
Many people take solace in the comforts offered by religion in a universe that clearly doesn’t care. In criticising the religious, Dawkins misses this survival mechanism. Perhaps he would make better headway tackling the failure of most education systems to teach critical thinking than by continually painting religious people as irrational.
Thornleigh, New South Wales, Australia
Tough call
In your article on using scanning methods to communicate with people in vegetative states (24 August 2013, p 14), Lorena Naci says caution would be required when giving patients a say in their care: “If they are depressed or not emotionally healthy, we wouldn’t necessarily act on their wishes,” she says, as an impaired decision-making process and a depressed outlook might well be clouding their judgement.
It would hardly be surprising or irrational for someone in such a condition to be depressed. Depression is misery. Forcing a person to remain alive in that state is cruel.
Norcross, Georgia, US
Chocolate balls
Being a bit of a foodie I decided to try your recipe for low-fat chocolate (21/28 December 2013, p 53). I also make various alcoholic concoctions such as bullaces (plum-like fruits) infused with rum, and Seville orange wine. I followed the recipe, replacing the water with the wine. I used white chocolate and added rum-soaked bullaces that I stoned, and some mixed nuts.
After two weeks I offered a piece to my son. He liked the taste, was rather disconcerted by the texture but what threw him completely was the way the chocolate bounced when he dropped it onto the table.
Bristol, UK
Degrees of certainty
Surely Philip Colfox does science a disservice in his letter in defence of economics by saying “nothing is certain” even in science (18 January, p 29). What counts is how certain. Science is in a better position than economics to isolate evidence and perform repeatable experiments.
Little Sandhurst, Berkshire, UK
Switched off
In his look at the cases of two people being kept on life support despite brainstem death diagnoses, Richard Huxtable said that US researchers could not find a single example of a person recovering after such a diagnosis (25 January, p 26). Unsurprising, since life support is normally withdrawn at this point.
Derby, UK
Waste galore
In his letter (25 January, p 31), Phillip Graham writes: “Local aboriginal tribes should be the only ones who decide whether to allow and profit from a nuclear waste repository. The site of the first nuclear test on the Australian mainland in South Australia would be a good place for consultations and geological studies.” It is important to remember that the quantity of radioactive fission products generated in a nuclear explosion is less than 1 per cent of what is present in a reactor at any moment, and that it is a very much smaller fraction still of what a reactor produces over its lifetime. Bear in mind also, that many reactors would contribute their waste to a dump.
I hope the local aboriginal tribes know all that.
Ely, Cambridgeshire, UK
It's a cover-up
Anil Ananthaswamy’s review of Thomas Suddendorf’s book considers a variety of ways in which humans might be considered unique in the animal world, each of which is found to be wanting in some respect (25 January, p 48). There is, however, one further characteristic of humans that distinguishes us.
We are, so far as I’m aware, the only species that deliberately and routinely hides its reproductive organs. Perhaps we should rename our species Homo cryptogenitalis?
Edinburgh, UK
For the record
鈥� In our look at wireless charging of electric vehicles (25 January, p 20), we should have said that the bus in Milton Keynes received a 120 kilowatts charge while parked over embedded power coils, not 20 kilowatts.