The biggest control knob: Carbon dioxide in earth’s climate history

[BPSDB] By Richard B Alley of Penn State University.

This was the keynote lecture at the American Geophysical Union meeting (a vast conspiracy of scientists to find out all they can about how the Earth works) last year.

It’s a good summary of what we know about the role of CO2 in the Earth’s climate, a proof that climate scientists really do take into account all the climate changes that have happened over the Earth’s history, and why that knowledge is still bad news for us as we belch huge amounts of buried carbon into the atmosphere.

Vodpod videos no longer available.

more about “A23A“, posted with vodpod

“Deep Waters Trust” out of its depth

Darwin in Shrewsbury [BPSDB] You might think that if creationists want to criticise the theory of evolution by natural selection, as understood and used by the overwhelming majority of biologists, then they would try to understand the theory. Especially as the series of meetings in Shrewsbury, Darwin’s birthplace, was billed as “an assessment of the evidence for design which has emerged through the advances in science since publication of his [Darwin’s] On the Origin of Species in 1859”.

I have already commented on the fact that there didn’t appear to be any books explaining evolution on the bookstall at the Meyer meeting. Perhaps the organisers were afraid that if they understood evolution they may come to be convinced by it.

That the Shrewsbury Deep Waters Trust misunderstands the theory is clear from the press release put out before the meeting. Obviously, to understand the theory properly, and how it agrees with the evidence, you need to read a lot more than I can write here.

1. Because we are based in his birthplace we see a need for a different approach to Darwin from the extreme positions of devotion and hostility that are commonly adopted: while we don”t accept the conclusions of modern neo-Darwinians about evolution we respect Charles Darwin himself – both for his theory of Natural Selection and for his honesty in acknowledging the possibility that evolution might be proved false. There is evidence in his writings and those of his contemporaries that shows where he believed his theories were in need of confirmation by future research.

Scientists are not “devoted” to Darwin, although admittedly there appears to be a lot of hostility to him in some quarters. The commemoration honours a great scientist – but scientist is the word.  All scientists expect that their theories (if important) will be tested and questioned in the future. This questioning and testing is called “research”. In the case of Darwin’s theory – evolution by natural selection – the theory was vitally important and had implications over a wide range of science.  It could have been disproved by discoveries, not only in natural history and paleontology (the study of fossils) but also by discoveries in geology and astronomy and even physics. And, especially, by discoveries in the new science of genetics which was just beginning, unknown to Darwin, during his lifetime.

All this evidence has tested the theory to the maximum, and it has survived, improved, since Darwin’s day. It’s the only theory that matches the vast amount of evidence that has been collected. And it is still being tested.

2. Christians believe that God, not random mutations, is responsible for the design that underlies the world we live in. Particular recent evidence of design of which Darwin was not aware is in DNA – the genetic code: it is a language, containing information that controls the formation and operation of cells. It exists independently of the material from which the cells are made.

It may come as a surprise to the Deep Waters Trust that evolutionary scientists, even the most atheistic ones, do not believe that “random mutations” are responsible for design, or the appearance of design, in living organisms. Darwin’s insight was the selection of particular organisms by the environment – those that reproduce most successfully in the environment – enabling their genetic material to persist and become predominant. This is called “natural selection”. Darwin knew nothing about the genetic mechanism, of course, but the fact that it is consistent with evolution in all respects is one of the successes of Darwin’s theory.

3. Evolution involves progress “up” the evolutionary tree, each step requiring the addition of information to the genetic code.

No, it doesn’t! This is a serious misunderstanding. Evolution is about adaptation, not progress. The outcome of evolution, as it has happened, is that there are some complex organisms (a few of which think they rule the world), but simple organisms are just as evolved. Think of the bacteria – they live and exist much as the earliest of their kind, but they have evolved to live in all sorts of ecological niches.  There is possibly a larger mass of bacteria on the planet than of all other organisms put together. And loss of function is common in evolution – think of flightless birds.

Random processes do not produce meaningful information. Some Christians believe God used evolution to bring about his purposes, producing more complex designs progressively by stages. Others believe the DNA evidence is better interpreted as demonstrating a gradual loss of information as species change through Natural Selection. (Loss of genetic information produces greater variety in sub-species, but not the ability to change from a simpler species into a more complex one.) The ancestors of today’s species would have been fewer, more elaborate, forms containing all the genetic information from which present day life has descended.

Creationists abuse the idea of “information” and “complexity” (which seem to be interchangeable to them) by using the words in different ways so that you think they are talking about the same thing when, really, they are changing the meaning as they go along. In fact, there does not seem to be any generally accepted definition of either “information” and “complexity” that applies in understanding evolution. Dr Stephen Meyer, in his lecture, used the Shannon definition of information (as was clear from the slides he displayed). This definition specifically relates to understanding the transmission of information down a predefined communications channel. What relationship it has to evolution needs to be demonstrated. Dr Meyer’s use of it seemed to be mainly to give an apparently scientific appearance to a non-scientific argument.

4. The debate is sometimes portrayed in terms of a conflict between science and religion, where science suggests that life has evolved as a result of random processes, while religion claims God has brought it about deliberately.

Some believe both these views can be held at the same time; others that they are mutually exclusive, and that only with “blind” faith – faith despite evidence to the contrary – can one claim that both are true. We believe there is a third position that needs to be explored: the possibility that the scientific evidence is best interpreted as confirming design, not randomness.

No, as I said before, no scientific theory holds that life evolved purely as a result of random processes. That makes a difference.

To make ID (or creationism) scientific, what you have to do is show that it makes specific predictions about the evidence (fossils, genetic makeup of species, or whatever) that are different from (the real) theory of evolution by natural selection. And then show that the actual evidence agrees with ID (or creationism) and not with evolutionary theory. This is the challenge to the Discovery Institute or anyone else. And ID and creationism have always failed this challenge.

5. We believe there is not one debate but two: one debate about interpretations of the scientific evidence – what has come to be known as Intelligent Design versus random processes – and another between two faith positions: an originally good world which has been in decline as a consequence of human wrongdoing, or an originally simple and amoral world which has been evolving into something more complex and better.

These are both false dichotomies – a logical error. Are there really only two possible positions in each argument? I can think  of many positions in each case. I won’t bore you with mine, except to say that my position is emphatically not a “faith” position, as I would change it if any convincing contrary evidence was presented.

Stephen Meyer’s book

Dr Meyer’s book has now been published. I shall not be buying a copy, as his lecture suggested that there was nothing in it that is both significantly new and interesting. Other people, better qualified than I am to do so, will no doubt be reviewing it in time, and I shall look forward to reading their reviews.

Dr Meyer’s main theme in the lecture was a bit like the following argument. Suppose he had claimed that it was impossible to create a baby, because it is highly improbable that all the chemical components of a baby could come together in the right combinations.  We would surely argue that he is wrong, because babies are not made by the process of assembling all the chemicals at once. In fact, a baby is assembled slowly by processes in which the baby’s genes interact with his environment (including the mother’s womb and the outside environment). Similarly, the evolved biosphere is a product of continual processes of interaction between the organisms’ genetic materials and their environments.


The Deep Waters Trust seems to have gone into hibernation since the event. There is no sign of the recordings promised from the February event. The aims of the charity are given as “The advancement of education in the public arena of the relationship of belief in a creator god based on the Holy Bible and scientific discovery, philosophy, theory and investigation”.

See also

Creationism in Darwin’s birthplace

Not quite so honest to Darwin (or anyone else)

More about Stephen Meyer’s lecture on Intelligent Design

Other creationists who crashed the Darwin party

Homeopathy Awareness Week: The facts of life

[BPSDB] Here’s a description of the process for producing a homeopathic remedy, as described on Wikipedia:

…homeopaths use a process called “dynamisation” or “potentisation” whereby the remedy is diluted with alcohol or distilled water and then vigorously shaken by ten hard strikes against an elastic body in a process called “succussion”. … During the process of potentisation, homeopaths believe that the vital energy of the diluted substance is activated and its energy released by vigorous shaking of the substance.

… A 2C dilution requires a substance to be diluted to one part in one hundred, and then some of that diluted solution diluted by a further factor of one hundred. This works out to one part of the original solution mixed into 9,999 parts (100 × 100 -1) of the diluent. A 6C dilution repeats this process six times, ending up with the original material diluted by a factor of 100-6 = 10-12. Higher dilutions follow the same pattern. In homeopathy, a solution that is more dilute is described as having a higher potency, and more dilute substances are considered by homeopaths to be stronger and deeper-acting remedies. The end product is often so diluted that it is indistinguishable from the dilutant (pure water, sugar or alcohol).

Now for some real science, what you learn in chemistry at school. A ‘mole’ of any substance – for water 1 mole is 18 grams – contains approximately 6 × 1023 molecules of the substance, that’s 6 followed by twenty-three zeros (6 × 1023 is called the Avogadro constant).

That seems an awfully large number of molecules, but if you carry out the homeopathic dilution you soon reduce the concentration of the substance to effectively nothing. Suppose you start the homeopathic preparation with about a tenth of a mole of the active ingredient in 100 ml, by the time you have a 12C remedy (diluting by 100 twelve times) there is only, on average, approximately one molecule in every 100 ml. Homeopaths typically use 30C or even 200C solutions. Once you get to those dilutions, there is absolutely no chance of finding any of the original remedy in a sample. Such a homeopathic remedy consists only of the inert basis substances (water, alcohol, sugar, chalk etc.) that are used for making the dose or pill, like the placebos that clinicians use in tests.

Kate Chatfield of the Society of Homeopaths was asked by a House of Lords Select Committee:

“Is it possible to distinguish between homeopathic drugs after they have been diluted? Is there any means of distinguishing one from the other?”

She replied:

“Only by the label.”


Nevertheless, homeopaths still claim that the dilution process somehow makes a “remedy” more effective, even hinting at danger if the “strong” remedies fall into untrained hands. How this happens appears to be magic, the same way magic happens in the Harry Potter books. A few more scientifically-minded homeopaths have tried to come up with a pseudoscientific explanation called “memory of water”, but they have yet to put even a proper theory to this name, let alone find any evidence that it exists.

For the sake of argument, let’s just assume that the homeopaths are right, and that succussion does turn the material that you started with into an effective “remedy”. By the homeopathic “principle” that “like cures like”, the homeopathic solution should produce the symptoms of the disease that the “remedy” is used to treat.

In practice, even the very purest available water contains parts per trillion or parts per billion of numerous impurities. These chemical substances are in the water because the world we live in is made out of chemicals (they are not necessarily man-made pollution). Typical impurities would be common ions like sodium, chloride (that is, salt), calcium, magnesium,  iron and sulphate. There are likely tens of thousands of impurities in the form of molecules and ions at this level or lower. We don’t expect homeopathic “remedies” to be prepared with water this pure, which is expensive water used for chemical analysis and other experiments in labs requiring high accuracy. We happily drink water with higher levels of impurities than this – at those levels they have no significant affect on the human body.

So, even if a homeopathic “remedy” is prepared with the very purest available water, there may still be something like 1012 (1,000,000,000,000) molecules each of numerous impurities in a 30C or a 200C remedy and this level cannot be reduced. Of those molecules, some molecules of each impurity have been through the whole dilution/succussion cycle, so the impurities have been “potentised” too. So a homeopathic “remedy” ought actually to deliver the effect of many thousands of uncontrolled chemical substances. Fortunately it doesn’t – imagine drinking potentised Epsom salts. That’s because the whole idea of “potentising” is nonsense.

Even worse, if homeopathy were true, it would be potentially one of the most polluting industrial processes. Suppose the homeopath dilutes a commercial 6C “remedy” to 30C for a patient, each time diluting 1 ml to 100ml. Each stage generates 99ml of by-product, each more “potentised” than the next. That’s 24 × 99 ml, almost two and a half litres of stuff that supposedly will induce symptoms, and more than enough for treating the most hypochondriac of patients. It’s even worse for a 200C remedy – you would have almost 20 litres to dispose of.  How much of this strong magic water is flushed away and finds itself back in our water supply?  Fortunately, you could drink a lot of 200C and the only symptom you would get is a strong desire to pee.

The homeopathic manufacturer Helios has a catalogue that is good for a laugh. It consists mainly of lower “potencies” that your friendly local homeopath can make into “remedies” for you. Helios’s Excrementum can, for example, presumably does actually contain a small amount of dog shit. Sooner you than me. Marc Abrahams has more about this.

Yes. Be aware  of homeopathy. It’s homeopathetic nonsense.

Other creationists who crashed the Darwin party

[BPSDB]The “Shrewsbury Deep Waters Trust” were not the only creationists to take advantage of the Darwin celebrations in Shrewsbury. During March/April the Christadelphians sent leaflets throughout the town and set up a stall in the town centre advertising meetings – although they were not very efficient about it, as the leaflet came through my own door after the meetings had taken place.

The leaflet was produced by the Shrewsbury Christadelphians, although it seems likely that similar materials have been distributed elsewhere. What interested me was the quotation on the cover.

Darwin Question leaflet

Darwin Question leaflet

I asked the local Christadelphians, at their email address, for the source of the quotation, but I haven’t yet had a reply after five weeks.

I have searched on the web, where all Darwin’s writings are available, and have not been able to find it there. As far as I can tell, Darwin did not write a volume called “My life and Letters”. His son Francis put together a collection called “Life and Letters”. This contains one sentence that may be what the Christadelphians are referring to. This reads: “When we descend to details, we can prove that no one species has changed [i.e. we cannot prove that a single species has changed]; nor can we prove that the supposed changes are beneficial, which is the groundwork of the theory.”

If you do a search for the exact words, though, you will find it quoted widely on creationist websites, with the same erroneous citation. Quite likely, the Christadelphians simply lifted it from one of these. It is an example of what is often called called “quote mining” – selecting from the words of people who are perceived to be “authorities” in such a way as to change the apparent meaning in a favourable way. Creationists often use this trick to make it seem as if scientists are expressing doubt about evolutionary theory, or pointing out a problem with the theory that does not actually exist. In this case, I doubt if the Christadelphians are being consciously dishonest – it probably never occurred to them that something that is so widely quoted by their brethren could be wrong.

“Quote mining” is so prevalent that TalkOrigins, one of the best web resources on evolution, has a project devoted to it: you can find the misquotation I am referring to discussed here.

Selecting Darwin on this matter is misleading too: Darwin is not an “authority” on evolution as the Bible is an authority to Christadelphians. Darwin originated the theory of evolution of natural selection which continues to be the basis for a vast research project. Discoveries in genetics now mean that we can trace the evolutionary descent of huge numbers of species – which Darwin could not do in the state of knowledge that existed in his time.

Incidentally, the history of the Christadelphians makes interesting reading. They comprise a tiny sect that tries to uphold to an extreme the literal accuracy of the Bible. Not surprisingly, it has fractured into even tinier fragments as its members fail to agree on differences of doctrine that most of probably couldn’t even see. A probably inevitable consequence of believing that you know the absolute truth is that eventually you must believe that only you (and your followers) know the absolute truth.

Word: Theory

(revised text)

A scientific theory is fundamentally an explanation of phenomena. These phenomena may be observed in the world around us, for example, the tides in the oceans or the different varieties of living things. They may be observed with the aid of devices made for the purpose, for example, observing distant galaxies with a telescope or bacteria through a microscope. The observations we want to explain may also be the result of highly contrived experiments, for example, the collisions of particles in a particle accelerator or chemical reactions in glassware.

In ordinary life, we may look for explanations of single events, such as “who left the door open?”, “how did that batch get contaminated?” or “how did that person die?” We may even talk of having a ‘theory’ about how something happened. Usually this means that we are not sure about the explanation. If we are sure, then we would usually describe the explanation as a fact.

Scientists use the word “theory” in a very different way. A scientific theory attempts to do two things as well as explain. It attempts to generalise: to cover all the occurrences of a particular phenomenon. In the theory of gravity, there are not separate explanations of each individual case of gravitational attraction, for example, falling objects on the earth’s surface. The theory describes what is common to all kinds of gravitational attraction, including objects falling on the moon, the tides, the motions of the planets and the structures of the galaxies. If you were looking at these different things without the benefit of a modern education you might not recognise that there was a single explanation linking these various phenomena. It took Newton’s genius to do that.

A good theory also unifies many different phenomena, where the connection may be very difficult to see. For example, the theory of plate tectonics became accepted during the 1960s because it explained not only old and otherwise inexplicable phenomena such as the existence of long mountain chains (like the Himalaya and Andes chains) that are mostly made up of tens of kilometres thickness of rocks formed from the erosion of older mountains, but also the new observations that were being made of  long volcanic ridges and very young crustal rocks under the oceans.

Observations are tests of theories. Most times when scientists build an apparatus to do an experiment, they have a theory in mind. If the observations that are made with an apparatus are not consistent with the theory, then of course the experimenter will check the design of the apparatus first, but if nothing can be found wrong with it, then the theory is refuted, and a new theory, or an improved version of the old theory, is required.

It is important to realise that, in science, the word ‘theory’ has no implication about how well understood a theory is, about how certain it is, or how many practising scientists in that field accept it*. A new theory must obviously go through a stage where most people regard it as provisional and not properly tested. This was the case with the theory of plate tectonics in the 1950s-1960s, although the theory had been around for a few decades before that. Nowadays, every practising geologist accepts plate tectonics, although there are always details that are in dispute. For example, we know that Iceland sits on a spreading ridge in the Atlantic, but there is currently disagreement over exactly what is happening under Iceland to make it such a prominent feature.

Similarly, there are no practising biologists, in fields related to evolution, who doubt that evolution by natural selection is correct, although there are always important details to be discovered and clarified. The important thing to remember is, that although we can never be 100% certain about a theory, there are many theories that we have no scientific reasons to doubt are fundamentally true. These include the theory of gravitation, which is used to make predictions of eclipses and other movements in the solar system accurate to fractions of a second. Well-established theories also include quantum theory and the theory of evolution by natural selection. The reason why these theories are accepted is that there is no other explanation in each case that fits the full range of obsrvations so well.

*Sometimes the word ‘hypothesis’ is used to describe a new theory that has not much observational support, but there is no consistency about this usage.

‘How can you deny my experience?’

[BPSDB] A few months ago someone commenting on a blog post (I think it was on Gimpy’s blog) described how some of his family were allegedly cured of illness by homeopathy, and asked ‘How can people deny my experience of this’?

I did not have time to reply on that occasion, but I thought that the question deserved a serious reply, and I considered how I would have replied to it.

To deny or belittle someone’s experience is a serious matter, especially when that experience has been a tragic one (which fortunately it hadn’t been in this case). For example, people who have pointed out the strong evidence that autism cannot have been caused by the MMR vaccine have found themselves accused of being sceptical or uncaring about the experience of the autistic children or their parents, even though that is clearly not the case.

So, if I respond to the homeopathy questioner, ‘no, I don’t think your family were cured by homeopathy’, am I denying his experience? The answer is ‘no’, but the reason is not an obvious one.

I would not deny the experience that the members of his family had the experience of being ill and getting better. As I do not know him personally, I cannot be in any position to deny or affirm it, but I tend to assume that people are telling the truth unless I have evidence otherwise, or unless the stakes are very high. In the interest of discussion, I accept that he had that experience.

Similarly I would not deny that the questioner’s family members had homeopathic treatment for their illness. Again, this is something I am happy to take his word on.

But that is not all there is to the claimed ‘experience’. There is an additional claim that they got better because of their homeopathic treatment. This is not an experience. It is an explanation. Even if the family members were made better by the homeopathic treatment, this explanation cannot be experienced directly.

An explanation is a story we create describing the supposed causes of events or phenomena. An explanation may be true or false, and we may sometimes be able to use our experience directly to confirm an explanation, for example, if we see someone knocked down by a car or shot with a bullet, we may be able to say that the cause of death was the accident or the shooting, and ignore the fact that the dead person had (say) serious heart disease or a brain tumour. But causes are rarely that obvious, which is why in cases of death we expect a doctor to certify the cause of death, with in some cases the need for an autopsy or an inquest.

In science, explanations are called theories. (I am simplifying here, but a scientific theory is basically an explanation for a whole lot of observations). The reason why science exists is that explanations are not obvious, and the most seemingly obvious explanation is often the wrong one. Scientists have to consider all the possible explanations for the phenomena they are studying, and try to weed out the wrong ones by looking for the evidence that contradicts them and shows that those explanations are wrong.

We are often led to the wrong explanations by the fact that we do not have all the evidence. We tend to jump to the conclusion that most pleases us and fits the evidence that we have (or that we are prepared to consider, because very often people ignore evidence that does not fit their preferred explanation).

As an example, watch the TV programme The System by Derren Brown if you get the chance. In this programme, Derren supplies a young woman with correct forecasts on the outcome of a series of races. By the fifth race, she has overcome her scepticism and is willing to believe that Derren has a ‘system’ that enables him to predict the results correctly, and she borrows a lot of money to place on Derren’s prediction for the sixth race…

What she doesn’t know (and apparently does not consider as a possibility) is that she is part of an elaborate version of a scam that is commonly used by share tipsters.The true explanation is simply that the programme team has sent out different predictions to a large number of people, and she just happens, by chance, to be the one who received all the correct predictions for the first five races. There is really no reason to suppose she has better odds than pure chance of winning on that sixth race. The evidence was not available to her (or she did not consider it) to determine the real reason for her winning streak.

Of course, there is a lot more to the programme than that, and Derren is too much of a showman to give all his secrets away. We know in all his programmes that he is keeping information from us. We understand that stage magicians do not really do ‘magic’ (the apparent explanation for what they do) but that if we had more information we would know the real explanation for the tricks that amaze and amuse us.

And yet… so many of us fall for the same ‘trick’ when it is done by nature rather than a magician. We jump to an explanation that does not take account of the knowledge  we do not have (or that we ignore). The questioner in the blog was in the same position as Derren’s ‘victim’ in the programme. She assumed that there was a ‘system’, even though she did not know the full facts and more knowledge tells us that this could not be the case. The homeopathy questioner assumed the ‘most obvious’ explanation, that the homeopathic remedies were responsible for the getting better. But that is not ‘experience’. There are other possible explanations, that the questioner’s experience cannot rule out. Most of these are impossible to discuss without knowing the details of the cases. But the  most obvious explanation is that the patients would have got better anyway without assistance. This is the explanation that homeopathy ignores, but science cannot. It is why science advances all the time, while homeopathy is stuck in a time-warp of ignorance.

To summarise: I do not deny the questioner’s experience that the patients got better, and that they took homeopathic remedies. But that the homeopathic remedies caused the improvement is not part of his experience. It is an explanation. The difference between science and homeopathy is that science is obliged to question this explanation and test it against evidence. Homeopathy does not do this.