Letters: Tangled worlds
In his letter of 18 April, Michael Abraham argues that a time traveller
cannot escape the grandfather paradox through the ‘tangled worlds’ theory
expounded by Marcus Chown (New 杏吧原创, Science, 28 March) because the
‘genetic make-up’ of the chronopathic killer would make him his grandfather’s
grandson in any world.
This argument is specious and entirely misses the point of the ‘tangled
worlds’ theory. My brother and I presumably have the same degree of genetic
indebtedness to my grandfather; if my brother were to take a sudden homicidal
turn and travel back in time to dispatch ‘our’ grandfather, would his genetic
make-up prove that I had done the deed? My shadow-self in some other skein
of this tangled multiverse is no more related to my grandfather than is
my brother (or am I).
It is remarkable to me how closely contemporary ‘many worlds’ theories,
and especially this latest ‘tangled worlds’ theory, parallel the rationalisations
of time travel in the so-called ‘golden age’ science fiction of the 1930s
to 1940s. Jack Williamson’s Legion of Time is the earliest story I remember
that dealt explicitly with the notion of ‘tangles’ among the possible parallel
universes. Robert Heinlein’s All You Zombies, which deals with the grandfather
paradox with a vengeance, has long been considered ‘the time travel story
to end all time travel stories’ by many science fiction aficionados. One
wonders what today’s cosmologists and theoretical physicists were reading
as teenagers.
Robert High New York, US
Letters: Tangled worlds
I disagree with Michael Abraham’s interpretation of the grandfather
paradox. He says that the time traveller can be shown to be a descendent
of the murdered man by analysis of his genetic make-up and therefore the
paradox is not resolved by the theory presented by Marcus Chown. However
this theory says there will be many versions of the grandfather with an
identical genetic make-up, all residing in concurrent histories. The time
traveller would have only killed one of these grandfathers, not the one
from his own history, and so will only prevent the birth of the version
of himself that would have inhabited that history.
It will appear to be a paradox only to an inhabitant of the history
in which the murder occurred. There is no such paradox from an omniscient
viewpoint.
Harvey Reall Banham, Norfolk
Letters: Pilot in peril
‘Wrong bolts sent pilot into the blue’ (This Week, 25 April). OK, not
a lot of marks for maintenance but, had the offending windscreen been plugged
from the inside, all that would have happened even if all the bolts fell
out would be that it would be pressed even harder against the frame/seal
due to internal pressure, not blown out as happened. So no marks at all
for design.
John Lindop Duddon Common, Tarporley, Cheshire
Letters: Sex-change chicken
We have kept chickens for many years purely for the indulgence of fresh
free-range eggs. The current population have been kept, as they say, from
the egg and the pecking order is well established. There is no doubt as
to which is chief chicken, as it exhibits all the usual manifestations
of being the boss including, occasionally, ‘treading’ the other birds in
imitation of a cockerel.
Recently, however, the bird has taken an even bigger step towards cockerelhood
– that of trying to crow. Indeed, it has refined its performance to the
point where it is indistinguishable from the real thing – to the annoyance
of our neighbours whom it wakes at unearthly hours.
Since these birds have never heard a cockerel nor presumably do they
know what one is, could it be that they have an archetypal memory of cockerel
behaviour in addition to hen behaviour? If this is the case is it precipitated
in a group of birds by the need for a ‘boss’ figure and only appears in
the bird at the head of the pecking order, or does that bird suffer a hormone
change which results in the appearance of the latent cockerelness?
In short, is this a case of Henopause requiring HRT (Hen Repopulation
Therapy) or has the bird just sexually freaked out?
M. A. Crooks Letchworth, Hertfordshire
Letters: Medicine market
I think that Donald Gould’s piece on restrictive medical practices is
very wide of the mark (Forum, 25 April). What he is advocating is a free-for-all
market. There isn’t space to debate market philosophy in medicine, but your
readers might reflect on some of the benefits of the British system. First,
it provides a method of accreditation for specialists, not simply qualification.
Secondly, the suggestion that patients should be able to ‘shop around’ for
specialist care is a prescription for disaster. The referral system may
not have operated as efficiently as it should (and that is often the fault
of doctors), but is has done a great deal to (a) ensure that care is provided
at the appropriate technical level, (b) contain cost, (c) minimise inappropriate
management and the risk of iatrogenic disease. Britain will abandon accreditation
in professional training, competition for consultant posts and the referral
system at its peril. Fortunately there is no chance of it happening, is
there?
A. J. Hedley University of Hong Kong
Letters: DOS dilemmas
Barry Fox’s review of Microsoft’s DOS 5 (Review, 11 April) is curious
in at least two regards. First and foremost, if he was so displeased with
the new operating system he could have done your readers a favour and service
by pointing to what many users regard as a better alternative, namely DR
DOS 6 from Digital Research. Among other much-welcomed advances, the latter
now bundles Stac Electronics’s Stacker, a file-compression programme that
permits one to effectively double the storage space of one’s present hard
drive.
Secondly, Fox’s admission that he has been unable to run Windows 3.0
under the new DOS is extremely curious, given that Microsoft developed both
platforms. I understand that this is the reviewer’s point, but were such
the rule I suspect that the hue and cry would have been momentous, given
that some ten million copies of Windows are now in the marketplace. I’ve
certainly experienced no such problems, which leads me to wonder about Mr
Fox’s own personal set-up, and whether or not he bothered to call anyone
at Microsoft’s technical support line in an effort to resolve this almost
unheard of problem.
Dennis Stacy San Antonio, Texas, US
Letters: DOS dilemmas
Barry Fox writes: The product was reviewed as a working tool, not a
computer buff’s toy. It was tested very thoroughly and many queries raised
with Microsoft. Following Microsoft’s advice (much of which was far too
technical for anyone but a computer expert), the product was tested a second
time. Essential work programs that ran with DOS 3.3 would still not run
with DOS 5.
Letters: Irreparable
Andy Coghlan states incorrectly in his article entitled, ‘Are power
lines bad for you’ (11 April) that mutations in DNA can be repaired. Premutational
damage occurs in cellular DNA molecules and this is either repaired accurately
by repair enzymes – in which case further damage is averted – or inaccurately,
in which case new, heritable DNA sequences are generated. Because these
new DNA sequences are now copied very precisely when they are handed on
from parental cells to their offspring they are called mutations: as such,
they cannot be distinguished chemically from any other ‘correct’ pieces
of DNA, and hence they are are not subject to enzyme-mediated repair.
I also take issue with a quotation in the article asserting that ‘real
harm’ could result if the number of errors in DNA increases by as much as
0.01 per cent. In fact, research has shown that no harm appears to result
even if the numbers of background errors (as opposed to fixed, heritable
mutations) doubles or trebles.
Donald MacPhee La Trobe University, Melbourne, Australia
Letters: Spoiled soil
I find your recent articles on the possibility of sustainable logging
of tropical rainforests often miss the point (‘Logging the rainforests the
natural way?’, 14 March). If indeed these forests are mostly growing on
very old and nutrient soils, then no matter how carefully trees are removed,
nutrients go with them and forest becomes degraded and eventually unsustainable.
This does not mimic natural destruction as the article implies.
(PS I love NS but will not renew my subscription unless the magazine
is printed on 100 per cent recycled paper.)
Bristol Foster Ganges, British Columbia, Canada
Letters: Reducing rubbish
Re your article, ‘Too many bottles break the bank’ (18 April). Recycling
is not the answer to the current and future crisis in refuse disposal. The
way forward is to reduce the amount of rubbish produced. In terms of the
domestic refuse scene, this can only be achieved by reversing the trend
towards disposability and cutting down on the variety of packaging materials
on the market.
The Women’s Environmental Network is demanding a return to refill and
return systems and that hazardous materials such as PVC are phased out.
Also that packaging systems which waste resources and cause problems in
recycling into new products are banned.
In its original incarnation the European Commission’s Directive on Packaging
and Packaging Waste embraced these goals. Now, however, it states that there
must be no discrimination between packaging materials (so refill systems
will not benefit); that countries who go further than the letter of the
directive may be prosecuted for infringement of free trade; that toxic additives
will be restricted by an arbitrary cumulative total limit, and that incineration
is of equal environmental value to recycling.
It is worrying to think that the European Community may soon act as
a brake on environmental measures taken by member states. It is now up to
individual countries’ MEPs and environment ministers to reverse the directive
before it is ratified. Let’s hope they don’t let us down.
Ilana Cravitz Women’s Environmental Network, London
Letters: Yank tanks
President Bush’s ‘green’ initiative, to allow polluting industries in
the US to buy up and scrap pre-1971 cars instead of attending to their
own dirty emissions (This Week, 4 April), needs to be shown up for the cheap
publicity stunt it is. Oil companies and other major polluters who are reluctant
to invest in new low-emissions technology are being offered a cheap way
out at the expense of America’s stock of classic cars. Environmentalists
have just as much cause to be annoyed as lovers of the ill-fated ‘Yank
tanks’.
Bland declarations from the White House that this kind of thing ‘reduces
reliance on imported oil’ are a sick joke, coming from a pro-oil government
which refuses to be tied down to stabilising carbon dioxide emissions and
threatens to upset the forthcoming Earth Summit in Brazil.
The refusal of a small sector of society to turn its cars over to the
rapid cycles of fast moving consumer goods provides the rest of us with
examples of durability and long-life technology, not to mention nostalgia.
Detroit never intended the cars of the Fifties and Sixties to last for
30 years or more, but many have done so. At a time when giant car manufacturers
are scrambling to introduce ‘recyclable’ components into their latest models,
long-lived ‘reusable’ cars sustained by spare parts remanufactured in small
workshops are bucking the trend.
Individual old bangers and hot rods may seem like pollution machines
alongside the latest low-emission, lean-burn, electronic engine management
technology, but their combined population is a drop in the ocean of today’s
congested road networks, where all the benefits of modern engine design
are wiped out by increased vehicle usage.
Until the US and other countries can grasp the nettle of designing better
public and private transport systems which use less energy and produce less
pollution in total, measures such as ‘cash-for-clunkers’ deserve only contempt
from environmentalists and car enthusiasts alike.
J. M. O. Scurlock King’s College London
Letters: Program protection
I was delighted that Tam Dalyell devoted so much of his Thistle Diary
to the threat posed to the European software industry by the GATT agreement
(25 April). As he pointed out, computer programs are not a suitable subject
for patent law. Attempts to apply patent law to programs have proved disastrous
in the US.
The other side of this ‘double whammy’ is the attempt to import US-style
copyright law via the European Directive on Software Copyright. The government
must implement this directive in British law by the end of this year. In
doing so it must take great care to exclude the kind of interpretation of
copyright law that is being made in the US. The major worry is the extension
of copyright protection to cover the ‘look and feel’ of computer systems.
There have been a number of US legal cases in which companies have been
sued for marketing a similar looking program, even though the underlying
implementation is completely different. If these cases are successful then
it will set back attempts to introduce common standards into computer software.
It will be as if the Ford Motor Company had been granted copyright on the
layout of controls in their cars, forcing each manufacturer to arrange its
pedals, levers and switches in a different way. This sort of chaos currently
exists in the computing world. We must help to end it by excluding interface
design from software copyright.
Alan Bundy Edinburgh Computing and Social Responsibility Edinburgh