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Don’t trust the scientists

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A couple of years ago Channel 4 showed a programme that presented an alternative view of climate change, “The Great Global Warming Swindle”. In this, various scientists presented claims that global warming isn’t the result of human activity (“anthropogenic”), but rather the result of natural forces. The programme generated a fair bit of controversy, which is probably what Channel 4 wanted. I won’t address the claims of the programme directly, but rather on what the programme, and the controversy, teaches us about science, and about the way the media deals with science issues.

In another post I talk about the way in which knowledge is socially constructed, such that a given group in society will find some knowledge claims acceptable, and others unacceptable. What I didn’t talk about is where the knowledge claims come from in the first place. For many of the articles in Conservapedia (the subject of the other post) the knowledge claims come from faith. For most in modern society though, such claims have limited acceptability. Science is seen as a more acceptable way of producing knowledge claims. However, scientists can often be seen to disagree with one another, which makes us wonder why it is that science is regarded so highly. The kind of disagreement shown in the Channel 4 programme illustrate both the weaknesses, but also the strengths, of science as a way of knowing.

Simplistically put, science involves making observations of some phenomena; generating theories to explain those observations, which then lead to predictions; and then testing those predictions. If the predictions are supported, then we can have some confidence in the theory. So, climate scientists observe an increase in global warming, and at the same time an increase in levels of carbon dioxide (CO2) in the atmosphere. Some then theorise that release of CO2 through human activity leads directly to the global warming. (Obviously the situation is more complex, but this will do for our purposes.) If this is true, then we might predict that continuing increases in CO2 levels will lead to continued warming. This has been modelled on computers, and seen to work. Most climate scientists now believe that CO2 levels influence global warming.

That all sounds fine, so why the disagreement? The problem is that there are other possible explanations for the association between CO2 levels and global temperature. For example, some claim that increased temperatures lead in some way to increased CO2 levels, rather than vice versa. The Channel 4 programme presented some of these alternative theories. The weakness of science is that we can’t actually prove any particular theory as being correct, we can only accumulate evidence for or against particular theories and at any given point, believe one theory to be more likely than the others. This is the position we’re in with regards to global warming, though as it happens the great majority of climate scientists now believe that the evidence points to global warming as being human induced.

The debate about global warming seems striking in comparison to the certainty of other scientific knowledge. However, some ideas that now seem well known facts themselves went through the same phase of disagreement. The best example is probably the theory of heliocentrism, the idea that the earth moves around the sun. This was first proposed in Ancient India, around 900-800BCE, and rediscovered repeatedly over the following 2000 years in different cultures. In European terms, the debate was re-ignited by Copernicus and Galileo in the 16th-17th Century CE, but took some time to be widely accepted: the Catholic Church first allowed heliocentric books to be printed in Rome in 1822CE. These days, you’d look foolish suggesting that the earth didn’t move around the sun, although that doesn’t stop some (http://en.wikipedia.org/wiki/Modern_geocentrism). The important point is that the heliocentric view became accepted gradually on the basis of an accumulation of evidence: it’s seldom the case that scientific ideas are suddenly accepted outright.

The weakness of the scientific method is also its strength. When science is done well, then people present their evidence and their reasoning when presenting a theory: this evidence and reasoning can then be checked and tested by others, and found to be valid or wanting. Science can be seen as self-correcting, such that eventually a consensus position is found that most people can agree on. This checking process is illustrated in the case of one of the scientists represented in the Channel 4 programme, Dr Eigil Friis-Christensen. He published three papers purporting to show that global warming was caused by non-human factors: each was shown to be wrong. The second and third papers responded to observed errors in earlier papers in order to provide a new theory for the same underlying idea, that global warming isn’t caused by humans.

Clearly, Dr Friis-Christensen is committed to the idea that humans don’t cause global warming, and clearly he’s eager to find some theory, somewhere, to justify this idea. It’s impossible to know why he’s so committed, whether it be a heartfelt belief; a desire to let humans “off the hook” for economic or political reasons; the result of funding from oil companies; or whatever. This commitment isn’t unusual though, a similar determination can be seen in attempts to “prove” racial differences in intelligence, as discussed in Gould’s “Mismeasure of Man”. At the end of the day, scientists are human. They have pre-existing beliefs that they are committed to, and that they are reluctant to discard. They make mistakes, that can lead them to false conclusions. Most evidence scientists collect is ambiguous, and can’t be definitively interpreted. This is increasingly being recognised, particularly in the field of the Sociology of Scientific Knowledge (http://en.wikipedia.org/wiki/Sociology_of_scientific_knowledge).

The important point is that scientific knowledge claims aren’t purely empirical and rational, but are affected by social factors. When you see a single scientific claim, be sceptical. Look to see what the evidence is, and whether you find it believable. Look at the claims of other scientists in the same area, to see whether they’re compatible or competing, before deciding which claims you believe. And when you come to believe a claim, don’t over commit, because the claim may be disproved at some later date.

As an example of the above, think again about evolutionary theory. The ‘Theory of Evolution’ presented by Darwin in ‘On the Origin of Species’ is specifically a theory of evolution by natural selection. Evolutionary theories had been around since the ancient Greeks, and particularly in Europe since the mid 18th Century. Before Darwin, many believed in Lamarck’s theory of evolution through inheritance of acquired characteristics, because it was then the best explanation for variation in scientific terms. However this theory had weaknesses, like, um, being wrong. Darwin’s theory won out because over time it became clear that it was better supported by evidence.

So, don’t trust the scientists just because they’re scientists: you’ll usually find others who disagree with them, which is an entirely healthy state of affairs. This insight is lost on the media however, who are usually happy to pass on the claims of anyone who seems to have the aura of scientific authority without actually thinking about it. This is clear with “The Great Global Warming Swindle”, where Channel 4 found some scientists who disagreed with the vast majority of climate scientists without bothering to look to see whether their ideas had any foundation. The fact that the programme would likely prove controversial undoubtedly added to the appeal, but in general Channel 4 is crap at doing science. Just look at their continued support for “Dr” Gillian McKeith.

For a good rebuttal of the claims of the programme, read this Guardian article:http://www.guardian.co.uk/commentisfree/2007/mar/13/science.media
One of the scientists who appeared on the programme as a denier of anthropogenic climate change is considering legal action against Channel 4 for allegedly duping him, and describes the programme as “grossly distorted”. The two main scientists on the programme were Professor Paul Reiter, whose Annapolis Centre for Science-Based Public Policy had received $763,500 in funding from ExxonMobil, the huge oil company; and Professor Ian Clark, whose Fraser Institute has received $120,000, also from ExxonMobil.

Don’t think I’m only getting at Channel 4 though: in general, the media presents science in a way that will maximise sales/coverage/viewing figures, with little understanding of the issues involved and even less attempt at reasoned analysis. The state of scientific journalism in this country is scandalous, mainly because ‘science journalists’ are journalists first, and very rarely scientists at all. For a considerably better example of science journalism, check out Bad Science (http://www.badscience.net/) which includes a couple of pieces on the Channel 4 programme.

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Written by daijones

September 11, 2010 at 7:03 pm

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Knowledge on the Internet

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You’ll hear us say at various times that you shouldn’t rely on web sites as sources to reference in coursework, though some sites are useful starting points to get your head round a question. Wikipedia’s particularly good, and particularly popular (too popular sometimes), but it has its problems. A study in Nature found that the accuracy of wikipedia articles wasn’t far short of Encyclopaedia Britannica articles. This is sound, but at degree level we expect knowledge beyond what you find in an encyclopaedia, no matter how good. More to the point, this level of quality comes about because anyone can contribute to wikipedia, but this is also its downfall – anyone can edit a wikipedia article to say whatever they want. The system is self correcting, in that people can flag disagreement and make changes to articles, and eventually articles tend to settle down to a sound position. Whenever you look up something in wikipedia though, there’s always a chance that you catch it at an intermediate stage where someone’s written any old nonsense.

The above is all true, and widely recognised. For most people, wikipedia is an excellent source, provided you bear in mind the fact that some material may be in dispute. For others, however, wikipedia is the front line in a dastardly plot by left wingers. Check out this Guardian article about Conservapedia, an online “encyclopaedia” set up to counteract the alleged left wing propaganda promulgated by wikipedia and the like:

http://www.guardian.co.uk/technology/2007/mar/02/wikipedia.news
(For the Conservapedia web site: http://conservapedia.com/Main_Page)

This development tells us something about the nature of knowledge. The people who set up conservapedia are dissatisfied with the knowledge presented on wikipedia, because it doesn’t fit in with what they, for whatever reasons, believe to be true. This is revealed nicely by their comments about the Democratic party – whatever your political views, any fair minded person would find it hard to believe that one of the two mainstream US parties has a ‘true agenda’ of cowering to terrorism.

The conservapedia site would seem to many to be politics presented as knowledge. The trouble is, this is usually true to some extent. It’s not always so blatant, but knowledge is fundamentally socially constructed, such that a given group comes to some agreement about what counts as “true” and what doesn’t. In some cases the given group is a clear subset of society with a clear agenda behind what they believe to be true. More widely though, any particular culture or society will have its own ways of agreeing what’s acceptable knowledge. In general in the West we prefer the scientific method as a way of finding ‘truth’, but the scientific method has its own flaws that means that just because some claim is widely accepted, doesn’t mean its true. In the 1940s most psychologists accepted behaviourism as a ‘true’ theory of human behaviour, but now we know better 😉 The lesson is always be sceptical about the truth claims of others. Including those on wikipedia.

Written by daijones

September 11, 2010 at 7:02 pm

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On Word Limits in Assignments

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It’s a commonly held belief that when you’re set an assignment with a particular word limit, you’re allowed to go over or under by 10%. So, for example, if the word limit is 2000 words then you’d be okay producing between 1800 and 2200 words. Outside of that range, you attract penalties for going over or under the limit. As is often the case, this belief is commonly held, but partially wrong 😉

Within the University regulations for assessment there’s no mechanism to penalise students for writing significantly less than the word limit. You can go under by as much as you want. On the other hand, there IS a set penalty for going more than 10% over the limit. If you go more than 10% over the limit then we’ll mark the work as normal and then apply the University’s standard penalty. This is that for every additional 10% above the allowance, inclusive, we take off 5 marks. In the case of an essay with a 2000 word limit, if you do 2190 words you’re fine; if you do 2230 words you lose 5 marks off the final mark; 2450 you lose ten marks, etc.

Having said that, word limits are there for a reason: it’s very difficult to produce a good answer in response to a given question in less words than the limit. While there’s no fixed penalty for going under the word limit, we set word limits in the expectation that students will need to write that many words, after selecting and rejecting appropriate material, to produce a good essay. If you find you’re well short of the word limit you will end up with a low mark because it’s a poor piece of work, in that you’ve probably left stuff out we expected to be included. The same actually holds true for going over the word limit also – if you write 2400 words for an essay with a 2000 word limit then you’re probably waffling a bit, and you’ll lose marks for that; and then lose more marks when we apply the penalty for breaching the word limit.

As a general guide, you should aim to write somewhat more than the word limit, but then identify the most relevant material to keep in to get down to the limit. Part of any assessment task is deciding what goes in and what doesn’t. If you find yourself short of the word limit think about what you might have left out that we were expecting you to include. Don’t though just pad out the essay to make up the words – the marker will notice irrelevant padding and you’ll lose marks for poor choice of material. If you find yourself well over the word limit, look for the least relevant material that you can remove. Remember we expect proper grammar, so just deleting every occurrence of “the” isn’t a good strategy!

Written by daijones

September 11, 2010 at 6:59 pm

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Eugenics never went away

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Written by daijones

September 11, 2010 at 6:53 pm

Posted in Biological determinism, Quick Link

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Gillian McKeith

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Written by daijones

September 11, 2010 at 6:51 pm

Posted in Pseudoscience, Quick Link

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“Gene for gullibility”

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Written by daijones

September 11, 2010 at 6:49 pm

“Neuromarketing”?!!

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Written by daijones

September 11, 2010 at 6:41 pm