Editor's pick: Some people without language can think
David Werdegar says 鈥渋t is impossible for us to think without language鈥� (Letters, 20 July). But people who have severe aphasia 鈥� loss of language abilities 鈥� because of strokes or other brain damage may be unimpaired in other thinking abilities, including arithmetic, logical and causal reasoning, chess playing, spatial navigation and theory of mind (thinking about the mental states of other people).
This doesn’t mean that language isn’t one of the wonders of the human brain. We shouldn’t, though, overestimate the extent to which other cognitive capacities depend on it. It isn’t clear what this tells us about the thinking abilities of other species, because their brains differ from ours in many ways, but their lack of language doesn’t justify the claim that they can’t think.
Little Sun's 'social change' doesn't change enough
The news from Olafur Eliasson that Little Sun lamps increase the homework efficiency of girls in households without electricity by 80 per cent isn’t inspiring: it’s a sad story about the unequal expectations for boys and girls (13 July, p 28).
I support the health and safety and climate justifications for replacing oil lanterns with solar-powered LED lamps. But describing how they enable girls to do the dishes and their homework while boys only do the latter tells girls that they can study and still have time to take care of everyone else. Where does that extra time come from? Most likely from either sleep or play 鈥� time that a boy gets but a girl doesn’t. Unless this extra homework time leads to increased opportunities for girls, will it really matter in the end?
We and our microbiome can have diet advice (1)
Clare Wilson does a good job revealing the pitfalls of most studies looking at diets (13 July, p 32). She could also have mentioned the emerging discoveries of the health effects of the composition of our microbiome 鈥� the organisms in our gut and on our skin, for example. Perhaps knowledge of how changes to diet can affect this composition will become the next form of dietary advice when it goes mainstream.
We and our microbiome can have diet advice (2)
Wilson correctly points out the limitations and inconsistencies of observational studies based on questionnaires, and the inability to perform randomised controlled studies of diet and health. She concludes that the problem is serious enough that we should be sceptical of all dietary advice.
But there are studies that examine health differences in geographical populations with different diets: for instance, those comparing northern European populations that typically consume more animal-based fats with southern European populations whose diets feature fish, vegetables and olive oil.
Other studies compared the health of Japanese immigrants to the US who adopted typically lower-quality American diets with those in Japan who followed a traditional diet.
Studies comparing vegetarians with meat eaters support the value of a vegetarian diet.
Experiencing a feeling of frustration about qualia
Trying to explain away the 鈥渉ard problem鈥� of consciousness, Rowan Hooper claims qualia are illusory and so there is nothing to explain (22 June, p 34). He says 鈥渨e don’t normally talk about our qualia, we talk about things such as being tired鈥�. But that misses the point.
A smartphone can register that its battery is low, display a low-battery icon on its screen and shut off safely when its power level gets too low. But nobody would claim that the smartphone 鈥渇eels tired鈥�. It isn’t experiencing tiredness in a conscious way like a human. It experiences no qualia.
That is the problem to be explained, and no amount of hand-waving about 鈥渋llusions鈥� will make it go away. Even if qualia are illusory, the hard question remains: how is it that such illusions produce a conscious experience in a human brain?
Is it worth studying the health of toothless people? (1)
Debora MacKenzie reports that infection with Porphyromonas gingivalis, a bacterium involved in gum disease, may cause a variety of serious diseases (10 August, p 42). I have heard that having all one’s teeth extracted was a not uncommon 21st birthday present in parts of England until the middle of the 20th century. It would be interesting to know if any similar studies have been carried out on the health of people without teeth.
Is it worth studying the health of toothless people? (2)
Assuming that people who have no teeth at all wouldn’t be troubled by plaque-dwelling bacteria, I wonder whether any correlation has been sought between toothlessness and the prevalence of the diseases identified by MacKenzie.
The editor writes:
These bacteria can get into your bloodstream just by chewing, so even having all your teeth pulled at an early age may not prevent exposure. Others will be toothless because of gum disease 鈥� the cow is out of the barn for them.
How could evolution arise from conscious agents?
Donald Hoffman claims to have used the theory of evolution by natural selection to discover that what we perceive isn’t objective reality, but an interface with it (3 August, p 34). He says evolution itself may be just an interface projection of deeper dynamics stemming from a network of conscious agents. But such agents arrive late in the fossil record, so how could evolution arise before they existed?
When super-rotation was still an incredible idea
In her excellent article, Leah Crane mentions that the atmosphere of Venus 鈥渋nexplicably rotates 60 times faster than the solid planet鈥� (22 June, p 42). We first learned of this implausible phenomenon when Desmond King-Hele discovered that Earth’s atmosphere about 370 kilometres up than it does near the planet’s surface.
King-Hele developed the physics of orbital mechanics to detect the effects of atmospheric drag on satellites. He found that the rotating upper atmosphere causes a slow decrease in a satellite’s orbital inclination, and could then determine the rotation rate of the atmosphere at its altitude. My work at NASA Langley on the satellites, which released balloons in orbit, benefited greatly from King-Hele’s work. There was once scepticism about the idea of super-rotation. The discovery of the astonishing behaviour of Venus’s atmosphere seems to have established this phenomenon.
I applaud your hearty serving of wrasse
From Simon French, Totnes, Devon, UK
I very much enjoyed the quantity of wrasse in one issue (20 July, p 17, p 19 and p 34). Your report of a new purple species of fairy wrasse was followed two pages later by bluehead wrasse changing sex. Then, you quoted string theorist Timm Wrase.
For the record 鈥� 7 September 2019
鈥� Matthew Williams at Cardiff University, UK, and his colleagues created 鈥� on their own initiative 鈥� a 鈥渄ashboard鈥� that flags between 500,000 and 800,000 tweets per day related to Brexit. Of these, between 0.2 per cent and 0.5 per cent are classified as hateful, and about 0.2 per cent of those have tags for users’ locations in the UK (31 August, p 6).
鈥� Weight a moment: Galileo Galilei is said to have proved that the acceleration due to gravity that objects experience is unrelated to their mass (13 July, p 42).