Editor's pick: Robots do not make a market, so abolish it
Sally Adee discusses the rise of robot finance (14 October, p 22). This raises the question of why we have a stock market at all. The original model was that entrepreneurs competed for the savings of investors, who actively chose stocks themselves or employed professionals to choose. The collective wisdom of highly motivated savers produced a distribution of investment that was, empirically, superior to any monolithic government or corporation.
“Index funds” that merely track the performance of a stock market as a whole were always freeriding on the backs of active investors. Adee suggests they will dominate the market. Allocation of investment by incomprehensible algorithms leads to capital being invested for reasons that are not understood and would appear to have no relationship to efficiency or to anything other than the profits of those operating the computer systems. The stock market would then offer no benefit to society, and could be closed down.
Centralised allocation of investment would be transparent, if not efficient.
Sleep and Alzheimer's: fear and opportunity
Matthew Walker's report on the relationship between poor sleep and Alzheimer's disease is fascinating but also ominous (14 October, p 30). After all, one common cause of insomnia is anxiety.
If insomniacs come to believe that their poor sleep habits are putting them at risk of dementia, they will probably lie in bed worrying about this and get even less sleep!
First class post
From
I waited eight years for diagnosis. I am glad people are striving to help with the process Melanie thanks to work to develop a home spit test for endometriosis (28 October, p 15)
First class post
Walker states that the deepest sleep is most helpful in delaying the onset of Alzheimer's disease. Your sleep cycle chart shows that only the first 4 or 5 hours of sleep contain the slow, deep delta brainwaves that are claimed to help delay Alzheimer's.
So is it worth considering the alternative pattern of sleeping for short periods several times a day? Those using this method – allegedly including Leonardo da Vinci – seem to get away with less than average total sleep while still being successful. Maybe they are getting the benefit of the deepest sleep several times a day rather than only during the first two cycles at the beginning of an 8-hour sleep period.
The editor writes:
• All the phases of sleep have some benefit: Rapid Eye Movement sleep, for instance, is increasingly thought to help modulate emotions. So the advice would still be to sleep until you wake up naturally, fitting in all sleep stages.
In defence of gloom – and of optimism
I wish I could share the glass-half-full optimism about the environment that Julia Brown describes (14 October, p 38). But I don't see how her implied numbers add up. She speaks of ways behaviour can be “nudged” – and Richard Thaler won the Nobel prize in economics for that (p 4).
But we now number 7 billion, and a sizable proportion of those are severely undernourished and generally have insufficient provisions. It seems likely that we will number 10 billion by 2050, and for everyone to be properly provided for, global production of everything will need to double – assuming current consumption continues. Since we already consume the food and energy of two Earths, this is clearly impossible, and we all need to reduce our lifestyles drastically. Tweaking and nudging won't go anywhere near as far as will be necessary.
The only choice we seem to have is the mechanism by which we reduce. Shall it be by surviving calamities and catastrophes and allowing the strongest to continue to take the lion's share? Or shall it be careful, fair, rational and logical planning? I am clear where my choice would lie.
In defence of gloom – and of optimism
I couldn't agree more that positive thinking is the way to save the planet. Recently, the market research company Ipsos about their optimism or pessimism on climate change. Nearly 60 per cent of the global public believe we can and might solve climate change; but 14 per cent are climate fatalists – who believe we can no longer reduce the effects.
A shocking number of those fatalists are young: globally, 22 per cent of those aged between 16 and 34 agree that it is now too late to stop climate change. The figure in India is 39 per cent, and 29 per cent in the US.
Communicating the scale of the climate threat without clear messages on solutions has created dangerous fatalism. This is why , in partnership with , has launched .
Kurt Gödel and an incomplete universe
Anil Ananthaswamy mentions physicist Max Tegmark's belief that the universe is made of mathematics (2 September, p 30). The same article refers to Kurt Gödel's incompleteness theorem, which shows that mathematical systems powerful enough to define arithmetic have theorems that cannot be proven to be either true or false within the system.
So if the universe consists of mathematics, and any interesting mathematics is incomplete, is the universe incomplete? Could this have something to do with the uncertainty in quantum physics?
Seeing genuinely new colours on drugs
Readers have discussed the effects of hallucinogens on people with colour-blindness (Letters, 30 September). A person I know was once prescribed a drug, a side effect of which turned out to be hallucinations. These included colours that he had never seen before. He was not colour-blind: these were genuinely new colours.
The holds that the brain converts red, green and blue signals from the eye into a red-green and a blue-yellow difference and brightness – much as old analogue TV broadcasts did. The “space” of colours that this can describe is larger than that filled by vision. An over-excited brain area can presumably stimulate signals outside normal vision.
We should find a way to prevent hurricanes
We read a lot about preparing for future storms of ever increasing magnitude by fabricating more resilient buildings (23 September, p 22). What about tackling the problem at source and finding ways to kill hurricanes? They need certain conditions to feed on. Upsetting this equilibrium could destabilise them and cause their collapse. I wonder about setting off large explosions at critical points around the eye of the hurricane. Doing this while a storm was embryonic could have more chance of success, and doing it while it was over ocean should avoid loss of life.
The editor writes:
• This has long been discussed. We have observed that “the most powerful source of energy… the H-bomb, is obviously impotent as a means of actually destroying a hurricane” (). Then we spoke of tweaking a “delicate balance of meteorological factors”; but we reported online 56 years later that “decades of tests have generated only heated arguments and even lawsuits” (23 April, bit.ly/NS-hurricane).
Drones make it far too easy to go to war
David Hambling argues that military drone pilots deserve medals (30 September, p 24). Such drones have already changed things for the worse. Leaders of powerful countries know they have the superior military power necessary to win every battle. Their temptation is to go straight to war whenever weaker countries won't do as they are told.
They were once restrained by the need to justify the stream of flag-draped body bags that came back to their own voters: no more. This has to stop, and the worst among us have to be made to accept that there is a price that has to be paid for going to war. It must not be made cheaper, easier and more “efficient” or our leaders will resort to it more and more.
Were leech-wielding barbers on to something?
Sally Adee reports impurities in older people's blood plasma as a possible cause of ageing, and that introducing plasma from younger folk may offer some rejuvenation (30 September, p 39). Some of the benefit may result from removing old plasma. Could this account for the old practice of bleeding with leeches? And could regular blood donors be doing good to themselves as well as to others?
The editor writes:
• We don't know. But bleeding does not dilute old blood as plasma does. We would expect senescent cells to replace ageing factors fairly soon.
Baldness doesn't confer any disadvantages
Exploring why humans are “so scarily hairy”, you say “pity the human male”, who must “suffer the indignity of a receding hairline” (7 October, p 41). Baldness is a normal male thing and doesn't, in my experience, confer any disadvantages. Please don't let your values intrude.
Could this be a way to avert war?
The threat of war is rising again (23 September, p 30). Suppose the UN resolved, and everyone agreed, that in the next five years only women should be elected as national leaders. Would there be less conflict in the world?
Does anyone know how many wars were started by women?
For the record
• A found increased mortality among those consuming less than 3 grams of sodium (about 7.5g of sodium chloride) a day (Letters, 14 October).