Planet hotspot
Norman Myers has claimed
(26 February, p 12) that conserving a mere 25
“hotspots” covering just 2.1 million square kilometres鈥攍ess than 2 per
cent of the Earth’s land surface鈥攚ill do much to slow the current massive
rate of extinctions caused by human activity. I agree that conserving areas with
great numbers of endemic species is essential. But I see problems with such a
museum mentality.
In my mind’s eye is a vivid image shot from Apollo 8 of a tiny blue planet
rising above the surface of the moon鈥攁 view of the only
biodiversity hotspot known to us, certainly within a distance of many light
years. On our own heads be it if we accept anything less than biodiversity
conservation on a planet-wide scale.
Eternal truths?
The question underlying Michael Cross’s article on the philosophy of science
(Inside Science, 19 February) is:
do the laws of nature discovered by science
have the same quality of truth as mathematical laws such as Pythagoras’s
theorem? As Cross points out, David Hume said that inductive reasoning across
time is logically flawed. So the fact that
Newton’s laws have been proven in the past does not mean that they will still be
valid in the future.
This opinion is in surprising contrast to what many physicists actually
think. They are convinced that Newton’s laws will never be missing from
future introductory physics textbooks. Regardless of their limitations when
it comes to explaining microscopic phenomena or quantum mechanics, Newton’s
precise prediction of the time taken for an apple to fall from a branch to his
head will hold forever, in their opinion.
Every year, a huge number of new students in schools and universities and
uncounted technicians in industry critically evaluate these laws. Yet, since
their discovery in the 17th century, no contradiction of Newton’s laws has been
found.
I think what is missing from Cross’s reasoning is something like Occam’s
razor鈥攏amely Murphy’s law: “If something can go wrong, it will.” If
Newton’s laws were flawed, we would have found examples of this long ago. This,
despite our philosophical difficulties, supports physicists’ conviction that the
laws of nature discovered by science do have a similar quality of truth to
mathematical laws.
Letter
Cross comes to grief over Occam’s razor: “the simplest explanations are the
best”. If I find an airmail letter in my mailbox, I do not conclude that a bird
brought it, because this simple explanation requires ad hoc assumptions
difficult to defend鈥攅specially if the letter is addressed to me.
A complex explanation, involving many factors such as clerks, aircraft, and
motor vehicles, is more satisfactory than the simple one assuming literate,
altruistic birds.
Cross also faults Marxists for their poor record in predicting “a crucial
phenomenon鈥攑olitical revolutions”. Marx attempted to make his socialism
“scientific” by identifying the social force鈥攖he working class鈥攖hat
would bring a new society into existence, something that earlier “Utopian”
critics of capitalism had neglected to do.
And Marx did correctly predict that
worker-led social revolutions would take place. He did not provide a timetable,
any more than Darwin predicted when new species might appear. Both men
identified mechanisms for the introduction of new forms.
Is there any theory of society that could have predicted the exact date and
location of the Russian Revolution in October 1917? Or of the organised
demonstrations in Seattle 1999?
Letter
The philosophy of science is a controversial area, as many articles from past
issues of New 杏吧原创 would testify. “Science’s goal is to discover
the laws of nature,” Cross says. That is hardly a consensus position of
philosophers of science. It ignores the vibrant debate on what the “laws of
nature” actually are.
“We find these laws by collecting facts,” continues Cross. The implication
that scientists collect facts before they have a theory is very much a minority
position today.
And science “has the power ultimately to explain all natural phenomena…”
The humility is amazing! But how would anyone justify such a statement
scientifically?
Letter
Thomas Kuhn would have been horrified by the belief Cross attributes to him
that “science is just a matter of fashions and a kind of crowd psychology, with
nothing to distinguish it from pseudoscience”. In his book, The Structure of
Scientific Revolutions, Kuhn clearly states that “later scientific theories
are better than earlier ones for solving puzzles in the often quite different
environments to which they are applied”.
Hotter houses
In his letter, Benjamin Robinson wonders why there is no apparent interest in
heat recovery systems
(26 February, p 57). I am sure the main reason is the
insularity of architects, who feel that to copy others’ work is to deny their
own creative urge.
A better example on the subject of solar heating is St George’s School in
Wallasey on the Wirral. It was built in 1961, for 300 students. It was intended
to be totally self-sufficient in heating, using only solar radiation and the
heat generated by the occupants.
The local council, worried about the possible limitations of relying entirely
on solar heating, insisted on central heating also being installed. This was
removed after several years, having never been required.
The Open University uses this building in its technology course and concludes
that “it is very disappointing that the apparent success of the Wallasey school
revealed by the Thermal Research Group’s study has had an almost minimal effect
on British architects”. The building is now Grade II listed.
Can copy
In Technofile
(22 January, p 13), you say that the DVD Content Scrambling
System (CSS) is “designed to stop people making multiple copies of DVD-Audio
discs and DVD movies”. This is not in fact the case. It is quite possible to
copy a DVD without understanding or breaking the CSS, and indeed this is being
done en masse in South-East Asia.
What the reverse engineering of the CSS allows is for anyone anywhere to
create DVDs that can be played on any DVD player, regardless of the zone.
Imagine you have a piece of paper, with a coded message on it. You can easily
copy the piece of paper (and the message), using a photocopier. But copying has
nothing whatsoever to do with decryption.
Further, imagine that these pieces of paper with coded messages were your DVD
collection. A DVD player has to be able to decode the message to play the
movie.
If you want to be able to build your own DVD player, your player has to be
able to decrypt the code, just like existing players. Decoding is necessary for
playing; it’s not necessary for copying.
Bangers are best
Your article on a study showing that replacing an old car with an new one
produces more carbon dioxide than sticking with the old one
(12 February, p 21) made interesting reading.
There are, of course, many issues relating to new cars, pollution and the
economy. As long as the government continues to use the production of new cars
as an indicator of the state of the economy, we will tend to believe that the
car industry must be supported at all costs. We will labour under the twin
misconceptions that buying a new car causes a net reduction in pollution and is
somehow worthwhile for the economy.
Coupled with this is the problem that, as people become wealthier, they feel
more inclined to buy a new car rather than repair the old one, simply because
they can afford to. This is the “I’m rich enough not to worry about waste”
syndrome.
A return to the days when cars were kept for more than a decade, rather than
being replaced by the latest model every few years, would be no bad thing.
Nae goots aboot it
At the Rainhill locomotive trials, Novelty looked elegant when compared to
Rocket and Sans Pareil with their big boilers
(19 February, p 48). But she could
never have evolved into the 20th-century steam locomotive. She was, rather, the
ancestor of the one-coach “steam railcar” of the 1930s.
Her small boiler and tricky forced-draught mechanism could not have been
scaled up to make a machine with the steam-generating capacity and tractive
effort needed to haul heavy trains for long distances at high speeds.
There is a direct line of development from Rocket to the 203 kilometres per
hour Mallard and the 500-tonne Big Boys of the Union Pacific in the US. As
George Stephenson crudely but perceptively said of Novelty at Rainhill, “Eh mon,
we needn’t fear yon thing, he’s got nae goots.”