Virtual carbon
The concept of “virtual water” (8 November, p 8) seems applicable to all resource use. China can’t dig up enough coal, so it relies on “virtual coal”; France relies on “virtual uranium”; and the US on “virtual carbon”.
I wonder what the true emissions of the US would be if we were to include the virtual carbon embodied in, for example, goods imported from China. And by how much would the emissions figures for China and India plummet if the virtual carbon in their exports were accounted for?
鈥� A third of China’s carbon footprint has been attributed to its exports (2 August, p 6).
Going with a bang
Would it really be such a bad thing for space tourism to stall on the launch pad (1 November, p 5)? It borders on the obscene that the world allows private space flight when everyone with an ounce of sense knows now is the time to cut back on unnecessary carbon dioxide production.
Exhilarating though space flight may be, it is a luxury that a wealthy few may be able to afford financially 鈥� but even they cannot afford it from an ecological, or even moral, point of view.
I would not wish it on anybody in particular, but some very rich people dying in a huge crash would bring the point home.
From P. G. Urben,
You refer to an explosion of nitrous oxide in 2007 “for reasons which remain unclear” (1 November, p 24). The fundamental reason was quite clear: like most other nitrogen oxides, nitrous oxide is explosive. This has been known, if seldom realised, for more than a century, and the phenomenon is regularly rediscovered 鈥� the hard way. The late Leslie Bretherick concluded that few ever read his Handbook of Reactive Chemical Hazards, which seems to be regarded as talismanic, offering protection by mere presence.
Organic contaminants, such as lubricants, sensitise nitrous oxide, making it liable to explode with less provocation 鈥� and with more power. Those who choose propellants which are explosives as they sit, before mixing with a second component, must expect occasional 鈥� and devastating 鈥� explosions. Transport of liquid nitrous oxide is particularly unsafe, since slopping around in large tanks may generate hotspots by compression of entrained gas bubbles.
The one nitrogen oxide which is not explosive is dinitrogen tetroxide. It is also the most easily handled as a liquid, and as it is a more powerful oxidant than nitrous oxide, it still makes a useful propellant when combined with another fuel. It may be more toxic than nitrous oxide (itself far from harmless) but, unlike the latter, it can be seen, smelled and felt before it strikes. Easily detected poisons seldom kill.
Kenilworth, Warwickshire, UK
Looks good on paper
Holly Preston asks why New 杏吧原创 is not published solely online (1 November, p 20). Answer: it folds into my jacket pocket and goes absolutely everywhere with me until finished 鈥� breakfast, bathroom, morning tea and lunch in the cabin of my truck, on the tram, waiting in queues, or just relaxing in an armchair. It is also more gentle on the old eyes than the glittering screen.
Mailed hard copy is a superior distribution system of great sophistication and antiquity, not to be abandoned until its replacement is as good 鈥� if then.
From Maxine Dewhurst
Dear Holly Preston, please ask your teachers to debate with the class: the economics of publishing, with reference to its funding by advertising; the need for long-distance travel in the 21st century; and the question “are computers green?”.
London, UK
Non-materialist mind
Amanda Gefter’s article on the “cultural war” over the brain significantly misrepresents non-materialist neuroscience (25 October, p 46) and does a disservice to your readers.
Most participants in the 11 September symposium “Beyond the Mind-Body Problem: New Paradigms in the Science of Consciousness” at the United Nations were medical doctors or neuroscientists who work with them. We do not question materialist models of the mind-brain complex merely for ideological or political reasons. We want to move beyond them because we have not found them adequate explanations of mind-brain interactions, nor do they point to useful treatment plans.
Your writer’s attempt to smear scientists who are looking for new directions, while perhaps entertaining, is a poor substitute for thoughtful coverage of a growing area.
Indeed, the breezy explanation by Andy Clark that Gefter quotes: “There’s nothing odd about minds changing brains if mental states are brain states: that’s just brains changing brains”, reveals a fundamental lack of knowledge of mind-brain interactions. In such interactions, the mind state often changes the brain state as a result of new information or a new choice of attention. Information and focus are not material entities.
Thinking matter
The day before I saw Amanda Gefter’s article on the mind/body controversy (25 October, p 46), I presented a first-year general philosophy lecture covering the “thinking matter controversy” of the 17th and 18th centuries. In 1651, Thomas Hobbes’s book Leviathan stirred up a hornets’ nest with his claim that minds are material. He provoked many notable philosophers to insist against him that “thinking matter” is impossible.
Passion over this was understandable 鈥� and remains so even today 鈥� since material minds would obviously cast serious doubt on immortality and associated religious doctrines. The main objection raised to Hobbes was essentially the same as the “hard problem” that Gefter cites as the nub of the issue: the unintelligibility of any physical explanation of subjective experience. You thus nicely illustrate the continuing relevance of the history of philosophy, as so many problems are rediscovered while too often the lessons from past discussion are forgotten.
David Hume argued (in 1739 and 1748) that we should not anyway expect causal relations to be intelligible: if they are not, the alleged “hard problem” is not such a problem after all.
That lesson proved indigestible to philosophers before the 20th century, seduced as they were by an apparently intelligible Newtonian science, but quantum mechanics beautifully confirms how Hume was right. Opponents of “intelligent design” who want to learn more from this history could go to .
From Alex Charles
Whereas most consider David Hume to have discredited “intelligent design” as early as 1776, the argument between materialism and the dualism that holds that mind is separate from matter has had no such resolution. This is partly because neither can be considered an “empirical” theory. The dualist will not be convinced by empirical evidence, since in the dualist’s view this evidence presupposes a disembodied “thinking” soul.
Fremantle, Western Australia
Difference engineering
The paper in Notices of the American Mathematical Society to which A. C. Grayling refers (25 October, p 48) was written by three male mathematics professors and Janet Mertz, an oncology professor. It is a well-intended and thorough piece of research but, as always on this subject, it has its agenda. It is interesting to note that much of the research over the past three decades showing superior mathematical ability in males has been done by women.
The US College Board by race and gender, showing that consistently in all races, therefore all socioeconomic classes, and including all immigrants taking the SATs, males outperformed females in maths; and the higher a score, the more the boys with that score outnumber the girls.
Today as many females as males, or more, enter medical school and law school. The fact that women professionals in physics, maths and engineering are still a small minority is not due to a male conspiracy: men could never get along well enough to pull that off.
The suggestion that females with genius maths ability do not pursue it because they do not want to be considered “nerds” makes a condescending assumption about female geniuses. Men are by and large bigger and stronger than women. They have superior ability to negotiate theoretical space and to commit murder. They have less communications ability than women, poorer social skills, are louder than women and more promiscuous. Why should they have the same maths skills?
From James Fenton
A. C. Grayling quotes a view that “there is no innate difference in mathematics between the sexes”, concluding that the low take-up of maths by girls is due to a cultural attitude acquired at an early age.
There is another possible explanation, still assuming the same innate ability between the sexes in maths, or any other subject. This is that what determines whether ability is made use of is motivation or necessity. And motivation, surely, could have a genetic component as well as a cultural one.
Farr, Highland, UK
Limited probability
Clive Semmens is right to criticise (1 November, p 21) Tony Budd’s calculation of the risk of a “once in 100 years” event occurring within 60 years (18 October, p 20). But he falls into the same trap himself, ignoring the odds of a building blowing down more than once in the same year. The risk over the building’s lifetime is in fact 1 鈥� e-60/100, which is 45.12 per cent 鈥� not hugely different from Semmens’s 45.28 per cent, but theoretically important.
Widescreen dreaming
If it is truly possible that after watching a lot of black-and-white TV programmes you can dream in black and white (25 October, p 15), will watching a widescreen TV make you dream in 16:9 aspect ratio, rather than old-fashioned 4:3? Will we soon dream of menus offering chapter selection and extras? I rather look forward to the cast and crew interviews.
Sincerely yours
Alex Pentland’s work on “honest signals” is extremely interesting, but there is one important issue in the dialectic between them and the use of explicit reason, deliberation and forethought, that Mark Buchanan’s review did not make clear (25 October, p 44). It is possible to view “social cues” and explicit statements as two separate communication networks: but after a formerly implicit signalling system is made explicit it becomes possible to incorporate it in conscious communication.
For instance, Buchanan asserts that “mimicry is an honest signal of empathy”. And so it is, until a con man reads the review and begins consciously to mimic, to fake empathy. Or as the playwright Jean Giraudoux famously put it: “The secret of success is sincerity. Once you can fake that, you’ve got it made.”
For the record
鈥� We quoted views on civilian space flight safety held by G茅rardine Goh, who is legal counsel with the German Aerospace Centre and would like us to make clear that these views are entirely her own and are not necessarily shared by the organisation (1 November, p 24). She, with colleagues in the International Association for the Advancement of Space Safety, is researching and advocating issues of space safety 鈥� rather than pressing the UN to legislate, as we said.
鈥� In a moment of diffuse concentration, we wrote of “a draft law designed to diffuse conflict over water” (8 November, p 8). The aim of the draft is of course to defuse, as is that of this.
鈥� We suggested that if there were a second star in our solar system it would “banish darkness” on Earth (23 August, p 40). In fact it would still be dark about a quarter of the time. And the planets of 55 Cancri are not “circumbinary”: they orbit the larger of the two stars.
When the wind blows a bit
T. Robertson rightly highlights our unreasonable focus on renewable power and neglect of renewable heat (1 November, p 20). But his proposed solution, running wind turbines for heat at very low wind speeds, will not help. Turbines may have a tough time synchronising to the grid at low speed, but this is not a problem, since there is hardly any power in these winds.
A typical turbine will output its rated power at a wind speed of around 12 metres per second, and power increases with the cube of the wind speed. So at 3 metres per second only 1/64 of the rated power is available; a 1-megawatt turbine would be producing about 16 kilowatts.
Air source heat pumps running on renewable power with thermal storage (such as a hot water tank) are a far better solution.
Your statement that a “large 10-MW wind turbine would create at least 10,000 MWh/year” is also wildly off-beam? No one would build a turbine which ran on a load factor of 11 per cent, only generating full power for 1000 hours per year. Offshore turbines typically run at over 40 per cent load factor and thus generate 35,000 MWh per year.
Anthony Higham refers to a 10-megawatt wind turbine for every 1000 homes. Even at a very modest output of 10,000 MWh per year, which implies a load factor of only 11.4 per cent when over 30 per cent is the expectation offshore, that implies annual consumption of 10 MWh per home or 10,000 kWh. In Germany the rule of thumb is that a home consumes about 4500 kWh per year. Perhaps Higham’s home is among those already heavily festooned with seasonal lights?
鈥� We were making a conservative worst-case estimate of the power output of a such a turbine, to show that even in these cases they perform impressively. We agree that it is likely the load factor could be a lot better.
Not knot
Richard Elwes writes, “But what is it exactly about the conjurer’s knot that means it can be pulled apart just like that, but the shoelace cannot?” (25 October, p 32).
This immediately brought to mind the stunning demonstration that my son gave, aged 6, of his own method for untying his double-knotted shoelaces. He would simply pull one end of the lace with all his strength. The knot would come completely undone.
I witnessed this amazing feat several times. Now, at age 15, he unties his laces like the rest of us… apparently having accepted the impossibility of his more youthful abilities.
The editor writes:
鈥� He had inadvertently tied himself an unknot. But, as the feature made plain, that’s very easy to do without noticing.
Nomenclature hellenensis
Feedback refers to “proper terminology” in the naming of Bigfoot and goes on to refer to the name Anthropoidipes ameriborealis as being derived from Latin (8 November).
It is of course derived from Greek, as are many so-called Latin names. The key words, transliterated, are anthropos (man), eidos (form), pous or podos (foot) and boreas (north wind).
Market information tautology
Mark Buchanan writes about how speculative information causes people to act in stock markets (1 November, p 15). Last summer, the satirical newspaper The Onion ran a story headlined “Stock market rises ten points on rumours stock market would rise ten points”. Rings true, doesn’t it?
The editor writes:
鈥� Even better, we find many instances of people talking about such a story in , but we can’t find the original.
Engineering psychology
As an engineer who values psychologies’ tools, I was delighted to read Dorothy Rowes discussing whether psychology is science (November, p 18). I recall one psychologist being asked to find out whether vibration was a problem in helicopters.
He designed a perfectly balanced experiment comparing several frequencies of very severe vibration with a control case with no vibration. He asked subjects to do a search task for a few minutes while exposed, or not, to the various helicopter vibration frequencies. He proclaimed that there was no statistically significant difference between the test results and concluded that vibration in helicopters was not a problem.
He did not bother to use the tools developed in psychology to ask his highly motivated subjects to assess the severity of the vibrations. Nor did he find out how his tasks and durations compared with real life conditions. Had he done so, he would have found quite different answers. Instead he relied upon statistical processing to produce numbers, which it seems, is what psychologists seem to need to justify their work. He threw the baby out with the bath water!
We engineers need to use the very valuable subjective techniques developed by psychologists. Why don’t we all, including all psychologists, use them?
Driven to extremes
Congratulations to Devin Powell for his interesting interview with “hypermiler” Jack Powell (25 October, p 42). It is a subject of which we will become more aware and which we will all have to learn and practice.
However, the interview only went part of the way. A major cause of increased fuel consumer is braking followed by re-accelerating. This can be avoided by driving at very steady speeds, and maintaining momentum on approach to red lights in the expectation that you will have residual momentum when the lights turn green. For lights known to have a long red phase, I turn off the engine. This sometimes displeases the driver behind, who sadly may waste extra fuel energising his horn.
Of course, if one is of such a mind, further fuel savings can be achieved by not slowing down at corners and not stopping at all at red lights. The latter offers added fuel saving during the periods when one’s licence is suspended. These are probably included in the practices that Jack Martin doesn’t teach his kids.
Some drivers get better fuel mileage by selecting routes which avoid traffic lights at all, but the total fuel burn would usually be increased by the added length of their more circuitous route.
And the ultimate saving is made by not making the trip at all. Remember the posters at UK railway stations motto during the second world war: “Is your trip really necessary?”
From Bryn Glover
I read your interview with Jack Martin on hypermiling with growing irritation. I have been practising economical driving for many years, in a world where, obviously, most people do not. To expect anyone to be won over by the extreme nonsense being peddled by Martin would be quite unreasonable. Barefoot driving, ridge-riding, slip-streaming and tyre hyperinflation (highly dangerous and very expensive on tyres) are simply calculated to put any reasonable person off the notion on the instant.
There are two alternatives which are very easy to apply and which account for the vast bulk of any improvement, as opposed to the infinitesimal changes ridge-riding might bring.
Keep to speed limits and drive where possible at the manufacturer’s recommended cruising speed, about 90 kilometres per hour.
Anticipate the road ahead, and allow the car to slow under friction whenever feasible, that is, use the brakes as little as possible; I can travel for miles along non-motorway roads without a single touch on my brakes.
I drive a 2 litre automatic diesel SEAT Alhambra 鈥� not the best vehicle for achieving hypermileages, but needful for my lifestyle with grandchildren. Yet my overall cumulative average is better than 7 litres per 100 km, and I can easily achieve 4.7 l/100km as indicated by the car’s own display.
It really is very easy, and does not involve any of the nonsense Martin proposes. I would not disagree, however, with his implied advice not to use the phone whilst driving.
Cracoe, North Yorkshire, UK