Is there a learning speed limit?
Emma Young’s article on learning describes good learning practice (28 March, p 30). Yet we have little quantitative science about the process. There are two aspects of learning: absorbing novel information from the world, and introspection.
We can be forgiven for not understanding what goes on inside our heads, but there are scenarios where we can measure the rate of learning. There is that the maximum information rate of human learning is no more than a few tens of bits per second.
Sawbridgeworth, Hertfordshire, UK
<b>For the record</b>
鈥� California is not the largest of the United States, but the most populous (21 March, p 7). Apologies to Alaska.
鈥� We said electric cars emit “almost 20 per cent less heat” than petrol and diesel cars, when in fact they emit just under 20 per cent of the heat that conventional cars do 鈥� i.e. 80 per cent less (28 March, p 18).
鈥� Starting in September, all babies in the UK will be offered vaccinations against meningitis B (4 April, p 7). They remain at parents’ discretion.
Letters should be sent to letters@newscientist.com
Tripping gaily over the Date Line
鈥� Yes.
Tripping gaily over the Date Line
You say the launch of a mission to the International Space Station mission would be “on Friday”, and in the next paragraph “on 28 March” (28 March, p 6).
Could it be that it was 28 March in Kazakhstan but still Friday in the US?
Les Essarts-le-Roi, France
How does one shave a spider?
鈥� In the experimental group, spiders were anaesthetised with carbon dioxide then their white “moustaches” were removed with a razor blade under a dissecting microscope. In the control group, the spiders were anaesthetised, but this time the researchers scraped their moustaches with the blunt side of the blade, so as not to damage them.
How does one shave a spider?
Please, please can you tell me how to shave a spider’s moustache (14 March, p 17)?
Upminster, Essex, UK
Atheism, axioms, positing and proof
When I say I am an atheist, those with any religious belief will imagine it is their god that I don’t subscribe to. But to quote Freddy Mercury, “I don’t believe in Peter Pan, Frankenstein or Superman”. I don’t believe in Zeus or Hera either. A believer in the Christian god who doesn’t believe in, say, Shiva, is an atheist to a Hindu. If you accept someone else’s belief in another god (this is called religious tolerance) then you are doubting your own belief 鈥� which makes you an agnostic.
Houston, Renfrewshire, UK
Atheism, axioms, positing and proof
Both Steven Miles (21 February, p 54) and Alan Webb (4 April, p 54) talk about “true scientists” not accepting an axiom without proof. But the definition of axiom in mathematics and logic is that it has no proof. Axioms are simply posited, and proofs of subsequent theorems are built on them.
The notion of proof belongs in mathematics and isn’t applicable to contingent matters such as the existence of god. Here we should look instead to the balance of evidence and to the requirement to favour the null hypothesis until we have sufficient evidence to reject it.
Warrington, Cheshire, UK
Driven out of work when AI cars arrive
So far the main problems raised about driverless cars have been technical, with social aspects mainly concerning the safety of passengers and pedestrians (14 February, p 20). But no one has discussed their impact on jobs.
Long-distance haulage, taxis, buses and coaches will no longer need human drivers. There are 92,000 registered black cab and private hire drivers in London alone, and an estimated 300,000 active drivers of large goods vehicles in the UK.
I expect that human-driven services will become a rarity 鈥� reserved for socially significant events like weddings and funerals and those who like to drive for pleasure; if, that is, human-drivable vehicles are still made, and are affordable.
Sutton, Surrey, UK
Editor's pick: UK health service is good value
The UK’s National Health Service does cost more than it did when founded, but I dispute that this is the fundamental problem that Christopher Burke suggests (4 April, p 54). When it was founded, the UK was bankrupt after two world wars. Now we boast of being the sixth most healthy world economy.
We see attacks in the press that the size of the NHS workforce is second only to China’s People’s Liberation Army. We don’t see so much about the cost to the patient being among the lowest in the Western world and the quality of the service being among the highest. The potential costs to patients of an insurance-funded health service are fearsome.
I believe that perception of the problem of finance owes more to political ideology than to economics. In the meantime, practitioners are hampered by mushrooming systems of command and control. There is a gradual creep towards fee-per-item payment and treatment according to punitive protocols, all of which interfere with the practitioner getting on with the job.
As a general practitioner, I used to attend meetings about the nature of illness and how to treat it. Recently, virtually all my meetings have been about how to understand politically dictated targets and how to work them to minimise fall in income.
Bacup, Lancashire, UK
Smart horse, expensive cart
Researchers at the Children’s Hospital Los Angeles wonder why parental income appears to influence the intelligence of their offspring (4 April, p 16). Surely this is putting the cart before the horse: as this trend tends to persist over many generations, it seems logical to suppose that intelligence leads to high income rather than the other way around.
Professions that require intelligence tend to be better rewarded than those that don’t. Sport and entertainment may be exceptions. Would the income of sport and entertainment stars and their children’s intelligence show the same relationship?
Whitwell, Isle of Wight, UK
The humanities have truths, too
I disagree that “the scientific method… is still… the best way to distinguish what we believe from what we know” (4 April, p 5). The phrase “scientific method” tends to be used of study in which the data obtainable are quantifiable and have a high degree of certainty. Humanities researchers often try conscientiously to test their theories against reality. Their “facts” may be uncertain and unquantifiable, but when taken together and pointing in the same direction may lead to conclusions with a high probability of being correct.
Economics is a warning. Perhaps struck by physics envy, many economists seem to have become ever more mathematical in their theories, but to have lost the desire to test their ideas against what has been actually happening. The result was a failure to see the credit crunch coming. They would have been wiser to stick to the methods of the humanities.
Birmingham, UK
<b>Weekly social</b>
“Nothing about a vortex is tranquil”
about our Picture of the Day of super-typhoon Maysak
Belief, diversity and evolution
In his fascinating look at belief, Lawton concentrates on the distinction between knowledge and belief. But the philosopher David Hume argues that we find actual knowledge only in maths and logic: everything else is belief, to which we ascribe probabilities based on our experience in the world. Such belief is obviously subjective, but it also becomes the basis of science via shared and repeatable experiments.
The distinction between belief and faith is more telling. We can believe in something when we have evidence for it. But faith is a belief in something without evidence, indeed often in the face of evidence.
Folkestone, Kent, UK
Belief, diversity and evolution
Lawton quotes psychologist Peter Halligan as saying: “The prime directive of the brain is to extract meaning. Everything else is a slave system.” The purpose of the brain is rather to take in data, process it and make decisions 鈥� with the objective of maximising the chance of passing on the animal’s genes.
Whether any meaning is or is not extracted in the process is a meaningless consideration.
Ruislip, Middlesex, UK
Belief, diversity and evolution
There is an evolutionary hypothesis for the strength of deeply held beliefs, outlined by Robert Trivers, who you have interviewed (8 October 2011, p 32). He thinks deceit is necessary for all living creatures in their quest for survival. As clever apes we find it impossible to deceive effectively unless we actually believe the lies we tell. We thus cannot rationally analyse these self-delusions. Just occasionally, however, when we retrospectively analyse some of our stupid behaviour, some hints of our own delusions may emerge.
Knowledge of this plausible explanation for irrational human behaviour has been comforting for me, even if it is a delusion.
Vaucluse, New South Wales, Australia
Belief, diversity and evolution
In his article on belief, Graham Lawton writes: “One of the most interesting things about belief is that it varies enormously from person to person, especially on issues that really matter such as politics and religion” (4 April, p28). My default “credulous brain” believes the premise that the formation of belief is an intuitive rather than a rational process and that deeply held, inflexible beliefs drive much conflict in the world.
It also strikes me that the enormous diversity of belief is a source of strength for our species, giving us flexibility, adaptability and options in coping with new challenges. The harm wreaked by fundamentalists and extremists is that they try to remove this diversity and impose uniformity, through moral imperatives, group interest and threatening violence towards dissidents.
I like to believe that by doing so they sow the seeds of the eventual destruction of the systems and societies they are trying to create, as they become unable to deal with new challenges that conflict with their rigid beliefs.
Great Shefford, Berkshire, UK