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Twin twister
Letters– Misreading prejudice From Tim Jackson In his article on the roots of racial prejudice Mark Buchanan quotes Lawrence Hirschfeld’s finding that children think a fat, black child in a police costume is more likely to grow up black than to grow up fat or become a police officer (17 March, p 40). I would, however, dispute the conclusion that for these children “race is more important than other physical differences in determining what sort of a person one is”. Could it simply be that 3-yearolds are sensible enough to realise that it is a lot harder to lose skin pigment than fat or clothes? It doesn’t take much observation to see that people change clothes daily, that adults are a different shape from children, but that skin colour tends to run in families. The child has no need to be aware that the uniform represents the wearer’s occupation; or that chubby kids and obese adults, while quite different in appearance, have the same type of deviation from the norm and might represent a personal trait; or that skin colour represents any of the characteristics assigned to race. These concepts are a lot more advanced, and Hirschfeld is imposing his own adult concepts to make assumptions about the child’s thinking. Rossendale, Lancashire, UK From Ernest Ager Buchanan considers several arguments for a genetic basis for prejudice, but misses a glaring one – that there was a survival benefit from being wary of strangers. Strangers may be identified by many different markers: skin colour, eye shape or hair colour to name but a few. People would not be hostile to colour but to difference. Chimpanzees or baboons will attack interlopers on “their” territory, and they will also attack neighbouring groups. No doubt they have their own markers to identify the outsiders. Evidence 22 | NewScientist | 31 March 2007
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for this inbuilt trait can also be seen in young children, who may be perfectly happy when introduced to other young children, yet often have a fear of unknown adults. Here, it seems, the “otherness” marker is size. Exmouth, Devon, UK
Sail the jet stream From Martin Allen Your article on “greener” aircraft never mentioned airspeed, concentrating instead on wacky designs (24 February, p 32). We know that Concorde burned more fuel per passenger kilometre than a subsonic plane. Turboprops burn less fuel than jets do, but travel “in the weather”, not above it, which is where the jet engine achieves best efficiency. Propellers driven by piston engines can be more efficient again. Real savings can only be made if people fly less, more slowly and much more intelligently. With reduced airspeeds, it could be
important to exploit the weather, following the jet streams in the same way that sailing ships, which used no fuel at all, followed the trade winds. Some passengers might, though, be put off flying by the variable schedules this would lead to. And let’s drop the carbon offset business and the continuing stupidity of in-flight duty-free sales, which increase weight and thus fuel consumption. We need to do all
of this and more, with legislative force, very quickly. Loughborough, Leicestershire, UK
Twin twister From Peter Haigh Douglas Hofstadter seems keen to introduce complexity where no need for it exists (10 March, p 46). In his thought experiment, a person is teleported at the same time to both Mars and Venus, with the apparently paradoxical result of the one person being in two places at the same time. The problem disappears entirely if the “self” of that person is considered to be just a product of the physical existence of the person and the present time in which they exist. The passage of time results in a continuous stream of new “selfs”. (Who am I? Where am I? When am I?) The “selfs” of the past are locked there and unchangeable, so it is irrelevant whether the “self” of the present owns them or not. The “selfs” of the future are unlimited in number and, once dispersed in space, are no more part of the one existence than twins would be. Something similar happens to all of us at the point of conception. At that time our “self” consists of a single cell that is then scanned and reproduced to become two identical cells (teleported). If they were not held in lockstep in time and place they could easily become two separate individuals. Sometimes that is exactly what happens and identical twins result – no paradox there at all. Bellevue Heights, South Australia From Brian Messent When asked why we need to challenge the common-sense idea of a “self” by Mike Holderness, Hofstadter makes two mistakes. First, he bases his argument on a thought experiment which is, so far, untestable. Maybe the reason we cannot simultaneously teleport copies of one person to two different places is the indivisibility of “self”.
Second, the copies arriving on Mars and Venus would be identical only in the instant of arrival. As soon as they experienced their first sight of the new environment they would be different people, even though they may appear outwardly identical. Of course there is the hardware, and some software, that we were born with, but the software that we collect throughout life never stops modifying itself. I am not the same person I was yesterday. Yes, this may sound simple and mechanistic, but anything further is bordering on the realms of spiritualism and religion. We should not allow our selfawareness to lead us astray. Lake Placid, Florida, US From Phil French In Hofstadter’s account of the “teleporter cabin” experiment two copies of you were created on separate planets. His discussion about the nature and location of the “self” seems influenced by the idea that your terrestrial body was destroyed in the teleporter cabin’s scanner. I have to confess that I forgot to destroy you. Afterwards, to spare myself embarrassment, I returned you quickly to where I’d found you. You didn’t appear to notice anything unusual. The two copies were made successfully but as you were apparently unaware of them, it seemed as if your “self” was completely unaffected. How far did my inefficiency affect the significance of the experiment? Reading, Berkshire, UK
A different animal From Joseph Bray I have to take extreme exception to your editorial saying that humans “should not expect to be radically different from other animals” (3 March, p 5). We are radically different. Any fool can see the differences. www.newscientist.com
23/3/07 4:59:08 pm
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for this inbuilt trait can also be seen in young children, who may be perfectly happy when introduced to other young children, yet often have a fear of unknown adults. Here, it seems, the “otherness” marker is size. Exmouth, Devon, UK
Sail the jet stream From Martin Allen Your article on “greener” aircraft never mentioned airspeed, concentrating instead on wacky designs (24 February, p 32). We know that Concorde burned more fuel per passenger kilometre than a subsonic plane. Turboprops burn less fuel than jets do, but travel “in the weather”, not above it, which is where the jet engine achieves best efficiency. Propellers driven by piston engines can be more efficient again. Real savings can only be made if people fly less, more slowly and much more intelligently. With reduced airspeeds, it could be
important to exploit the weather, following the jet streams in the same way that sailing ships, which used no fuel at all, followed the trade winds. Some passengers might, though, be put off flying by the variable schedules this would lead to. And let’s drop the carbon offset business and the continuing stupidity of in-flight duty-free sales, which increase weight and thus fuel consumption. We need to do all
of this and more, with legislative force, very quickly. Loughborough, Leicestershire, UK
Twin twister From Peter Haigh Douglas Hofstadter seems keen to introduce complexity where no need for it exists (10 March, p 46). In his thought experiment, a person is teleported at the same time to both Mars and Venus, with the apparently paradoxical result of the one person being in two places at the same time. The problem disappears entirely if the “self” of that person is considered to be just a product of the physical existence of the person and the present time in which they exist. The passage of time results in a continuous stream of new “selfs”. (Who am I? Where am I? When am I?) The “selfs” of the past are locked there and unchangeable, so it is irrelevant whether the “self” of the present owns them or not. The “selfs” of the future are unlimited in number and, once dispersed in space, are no more part of the one existence than twins would be. Something similar happens to all of us at the point of conception. At that time our “self” consists of a single cell that is then scanned and reproduced to become two identical cells (teleported). If they were not held in lockstep in time and place they could easily become two separate individuals. Sometimes that is exactly what happens and identical twins result – no paradox there at all. Bellevue Heights, South Australia From Brian Messent When asked why we need to challenge the common-sense idea of a “self” by Mike Holderness, Hofstadter makes two mistakes. First, he bases his argument on a thought experiment which is, so far, untestable. Maybe the reason we cannot simultaneously teleport copies of one person to two different places is the indivisibility of “self”.
Second, the copies arriving on Mars and Venus would be identical only in the instant of arrival. As soon as they experienced their first sight of the new environment they would be different people, even though they may appear outwardly identical. Of course there is the hardware, and some software, that we were born with, but the software that we collect throughout life never stops modifying itself. I am not the same person I was yesterday. Yes, this may sound simple and mechanistic, but anything further is bordering on the realms of spiritualism and religion. We should not allow our selfawareness to lead us astray. Lake Placid, Florida, US From Phil French In Hofstadter’s account of the “teleporter cabin” experiment two copies of you were created on separate planets. His discussion about the nature and location of the “self” seems influenced by the idea that your terrestrial body was destroyed in the teleporter cabin’s scanner. I have to confess that I forgot to destroy you. Afterwards, to spare myself embarrassment, I returned you quickly to where I’d found you. You didn’t appear to notice anything unusual. The two copies were made successfully but as you were apparently unaware of them, it seemed as if your “self” was completely unaffected. How far did my inefficiency affect the significance of the experiment? Reading, Berkshire, UK
A different animal From Joseph Bray I have to take extreme exception to your editorial saying that humans “should not expect to be radically different from other animals” (3 March, p 5). We are radically different. Any fool can see the differences. www.newscientist.com
23/3/07 4:59:08 pm