Genes, Romano-British history and bullshit: analysis of a dispute

In July/August 2017 there was a bit of ‘disagreement’ on the social media platform Twitter, with some right-wing users attacking the BBC over an educational cartoon about Roman Britain, because some of the characters were shown with a darker skin than others. Sides were taken in articles and postings by experts and others on the question of ethnic diversity in Roman Britain. This same issue has popped up again on occasions since.

Mary Beard, the classical historian, emphasised what is known about the diversity of the Roman presence in Britain, and came in for considerable abuse from the far-right.There was an intervention on the other side from Nassim Nicholas Taleb, the statistician, who made various assertions based on genetics. It’s not my purpose to discuss these arguments here: it does seem that both sides talked past each other to some extent, especially in regards to the meaning of ‘diversity’. You can find more about this here and here and here (and other articles).

There is just one particular point I am interested in here, and it arises from an intervention on Twitter from Taleb, which I responded to at the time.

@wmarybeard: this is indeed pretty accurate, there’s plenty of firm evidence for ethnic diversity in Roman Britain

@nntaleb: Historians believe their own BS. Where did the subsaharan genes evaporate? NorthAfricans were lightskinned.
Only “Aethiopians”, even then

@nntaleb: We have a clear idea of genetic distributions hence backward composition; genes better statisticians than historian hearsay bullshit

Trying to leave aside the left-right political positions and the racist motivations involved in the wider discussion, this particular argument seems to reflect an idea that supposed ‘hard science’ (in this case, statistical genetics) trumps ‘soft’ (history/archaeology). I do not want to get into discussion of ‘hardness’ and ‘softness’ here, but I shall try to analyse Taleb’s specific argument about genetic distributions.

There are three sets of data in this problem. One is the set of data on the genes of the living population of interest, and another is the set of genetic data on the historic (or prehistoric) population that the living population is being compared with. There is also another set of data: the written records, archaeological finds and all other items that comprise what Taleb dismisses as ‘hearsay bullshit’.

All of these sets have their own specific technical problems. The historical data certainly have problems of interpretation amongst themselves: dating of objects and authorship or precise meaning of documents, for example, may be uncertain.

But collecting genetic data also has considerable technical problems: for example, obtaining reliable data from living populations is much easier than it is from fossils or human remains, as there are typically fewer remains than there are available living humans. Also the DNA from human remains may have degraded over time or been contaminated with other DNA, such as from microbes, and needs careful separation.

There is an additional problem with the data from both living and past populations: we have to be reasonably sure that the sets we have are representative of the populations they are taken from, since in neither case can we analyse the DNA of every individual. The genome of an individual is ‘data’ or an ‘anecdote’ to the same extent as a single archaeological find or written record is. It doesn’t tell us anything about the population until it is put into context with all the other similar data. This is a particular case where statistics is used: it is a mathematical tool to help us make a (probabilistic) estimate of the genetic composition of the population that our data sets come from. This is not an automatic process: it involves making assumptions and using the right statistical method, so it has its own issues and uncertainties.

We can think of the problem we are trying to solve here as a theory: how can we explain the genetic makeup of the modern population in terms of the genetic makeup of the past population at the period of history that is of interest? Looking at it this way, we can see that there is no ‘backward composition’ we can automatically use to derive one from the other, whether it uses statistics or any other mathematical techniques. The genetics of the modern population must depend on its history, as well as the scientific principles of genes. In the time that elapsed between the past and the present populations, we need to know what has happened to the population. Did certain groups migrate in or out of the population, was there mixing of different populations, was the population subjected to ethnic cleansing or genocide? These are questions that are very hard to settle, for example, to what extent did invading Anglo-Saxons displace the British currently settled in what is now England. Historians have good reason to believe that the Anglo-Saxons formed a new ruling class, and that some of the existing British were displaced by migration, but there is still dispute as to what proportions of the original population were killed or displaced.

So clearly we can’t ignore history here. The current genetic composition of a population is a result of both genetics and history. That history is part of the problem to be solved. Some of it will be attested by artefacts and documentation, some of it is purely hypothetical (and might be solved with assistance from the genetics). The point here is that the historical evidence cannot be dismissed: any theory, including reconstructing ancient populations, must reconcile all the relevant evidence, or it is simply inadequate. If it is contradicted by the evidence (and the evidence is not found to be defective), then the theory is false, and needs modification or replacement. The evidence here includes (at least) the available genetic data and the historical evidence, including written records and archaeological finds.

Note that I am not making claims about the actual history of Roman Britain here.  I don’t have the necessary expertise in the technical fields. I am simply trying to analyse the problem, to see why genetics is not in itself adequate to the problem, and the history cannot be dismissed. Solving the problem necessarily needs the technical expertise of the geneticists, historians and any others with relevant knowledge.

To see why the history is essential, consider the following scenarios (not an exhaustive list) that might happen to a population of interest:

  1. The population remains isolated from any other.
  2. A small number of immigrants arrives, they seize power and become the ruling class, and eventually merge with the main population through interbreeding.
  3. A large number of immigrants arrives and merges with the main population through interbreeding.
  4. A foreign power occupies the country, using troops from other populations, but remains largely separate from the main population. In the end it (largely) leaves.

All these scenarios will leave both different genetic traces and historical and archaeological data. Likely, given the inadequacy of the evidence, the problem will never be finally settled, as there will always be anomalies, gaps in the data and unsolved questions.

Statistics

Statistics is a branch of mathematics. Strictly speaking, it is fit only for analysing distributions of pure numbers. Whenever statistics is used as a mathematical tool in solving questions about the real world, other restrictions apply. We are then not dealing with pure numbers but with physical entities (and the concepts we use to understand those entities). In the particular problem above, these entities include people and their genes. In the physical world, these entities are subject to other principles, including the human lifecycle and the physical processes of genetic combination.

Sadly, statisticians, however good they are at statistics, can lose sight of this fact, and claim authority for statistics that is simply not justified. A very good example of this is in the supposed debate over human-caused global warming, where statisticians have weighed in on the ‘sceptic’ side with statistical analyses that simply ignore the laws of physics. One statistician has called this ‘mathturbation‘. Climate measurements are not simply numbers, they are properties (such as temperature or carbon dioxide concentration) of physical entities such as air or oceanic water, and our theories about them are part of physics.

In trying to understand things that happen in the real world, outside mathermatical textbooks, you can’t ignore the technical experts and their knowledge: statistics may prove them wrong, but only when correctly applied to the subject data.

Nassim Nicholas Taleb

The involvement of Taleb in this debate was very strange. He seemed to glory in taking the part of extreme right-wing participants in (sometimes vicious) attacks on historians on Twitter. He derided Mary Beard’s academic credentials, and frequently calls experts in other fields ‘bullshitters’. Yet his claim about genes and statistics reproduced above is bullshit, where bullshit is the term for not actually lying, but giving the impression of having knowledge he didn’t actually have.

Taleb’s background is as a statistician and a trader on financial markets. Financial markets are about the nearest thing in the real world to pure numbers, and mistakenly thinking that climate data are in some way similar to markets has led many people into error. Perhaps this confusion applies to other areas as well.

Taleb also seems to have a very thin skin, and has blocked me, and apparently many others who disagreed with him, on Twitter.

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The top of the slippery slope of woo-woo

Craig Murray, whose revelations on the sinister side of UK foreign policy I strongly commend to you, stands at the top of the slippery slope of “synchronicity”.

I find this worrying, because so much of what he says has the ring of truth because it is grounded in his own knowledge of diplomacy and diligent research, including through his contacts. Unlike most political journalism, which is based on speculation, ideology and wishful thinking.  A slide into woo-woo will inevitably devalue his work.

I have posted to his blog, rather cumbersomely:

I think the ‘order’ you are observing is the ‘availability illusion’.

We are involved – simply by default – in uncounted numbers of events, including all the people who pass us by in the course of a day, the things we see, hear and read, and so on.

Just by chance some of these things are going to be of more significance to us, in the light of our life histories, intentions and dreams. These are the things that we single out as coincidences, when in fact we experience countless coincidences every day, most of them meaningless to us.

To genuinely conclude that the ‘coincidences’ we experience are really significant, we should take into account all these background coincidences and the chances of them happening. That’s what science does.

But quacks, financial frauds, clairvoyants and politicians are well aware that we are prone to this availability illusion – one of the cognitive illusions that arise from the way our brains have evolved – and take full advantage of it.

Or, as EscalanteKid comments, rather more succinctly, on Craig’s post:

“the search after meaning is especially insidious because it always succeeds.”

Fake medicine and AIDS denial are ‘charitable’

[BPSDB] Richard Wilson wrote this about a registered charity that is actively promoting AIDS denial.

This reminded me that, last year, I wrote to the same Charity Commission to complain about Frontline Homeopathy, which collects funds to promote homeopathy as “as an effective, low cost primary health care system” in developing countries. I got this reply. The Commission’s criterion is ‘charitable’, which apparently has nothing to do with ‘true’ or ‘effective’.

Thank you for your request.

The Commission’s policy on registering charities who pursue practices which constitute alternative and complimentary medicine was made following our Decision on the application for registered charity status from the National Federation of Spiritual Healers. Please see the link below for more details (you may need to scroll down to see the specific case and our findings).

www.charitycommission.gov.uk/tcc/issueguidesum.asp

I trust you will find this useful.

Perhaps this is matter for another campaign by bloggers?

How people are manipulated by sleazy lies

Obama misleading clip [BPSDB] Contrary to what many people believe, the camera and its still image always lie. Our visual perception of the world depends on a jerky series of images that the brain interprets as continual motion. This is especially important as we interpret other people’s faces, which are expressive through their unending mobility.

Stop that motion through the mechanism of a photograph, and we are left with something, motionless, flat and two-dimensional, that we cannot help but try to interpret as if it were part of the moving three-dimensional world. Wise people realise that they are being deceived and deliberately try to treat the impression with scepticism derived from their knowledge of the world and the weaknesses of the human eye and brain. But these weaknesses are easily exploited by the unscrupulous when the people viewing the picture are unwary. I have seen pictures taken of audience members at political party conferences showing fleeting facial expressions that are then “interpreted” to make implications about the relationship between the listener and the speaker.

A spectacular illustration of this manipulation is a recent still from a video taken of President Barack Obama, reported here by Angry Mob and discussed by the MSNBC reporters in the embedded video. Observe how fast the steps of the action take place, and how the moving scene leaves no room for the misinterpretation that seems almost obvious from the still. It is not just that the photo completely deceives us about the situation, but that the still was clearly selected from the original video to give a false interpretation.

The human brain is prone to cognitive errors, not only in interpreting visual information, but in processing other kinds of data too. It is noteworthy that the kind of sources actively promoting this lie are the kind that are likely to use other cognitive errors in order to promote denial of the existence of man-made global warming, a phenomenon firmly established by scientific research. Some of this manipulation is undoubtedly deliberate, but in most cases the misinformation is passed on by people who themselves are willingly and unsceptically manipulated, because it agrees with what they want to believe.

“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.

Update

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

Follow-up to Homeopathy Awareness Week

[BPSDB] There was no follow-up to the letter published prominently in the Guardian on 13 June 2009, on which I have commented before. I have followed this up with a letter to the paper’s Readers’ Editor. I actually wrote on two different issues, so this is an extract from the letter.

On Saturday 13 June you published prominently a letter from three physicians (Dr Lewith et al). This consisted of an unfounded claim (see http://apgaylard.wordpress.com/2009/06/15/false-positives/) about evidence for the effectiveness of homeopathy, in which the signatories appear to have a direct financial interest.

I expect that there were many letters (including my own) in rebuttal of this claim, but none appeared in the paper. It appears to me that homeopaths and their supporters get an easy ride in the paper (outside of Dr Ben Goldacre’s columns) despite the fact that it is to medicine pretty much what astrology is to astronomy.

For information, this is the public information on the involvement of the three signatories with homeopathy:

Dr George Lewith

Dr Michael Dixon

Dr Peter Fisher

They all use the weasel word “integrative” or “integrated”, which has come  to be a warning sign for serious bullshit whenever it is associated with the word “medicine”. Homeopathy is fake medicine. It imitates the protocols and procedures of medicine (but not necessarily the ethics), while the theory behind it, and the remedies themselves, are as empty of real content as the magic in the Harry Potter books.

Spinning greenhouse gas numbers: good or bad?

[BPSDB] Spinning numbers in more ways than one. The explanation of the science is correct, and the purpose of the counter seems admirable. But of course, the supposed precision of the numbers is spurious.  (It grates on this former science lecturer, who used to have to explain why all the digits output on a calculator were just not significant.)

But, if the figure was displayed to a reasonable precision (maybe hundreds of millions of tons?), you just would not see the display updating. The whole point of the display is to convey how we are recklessly pumping carbon dioxide into the atmosphere, with consequences that can be calculated, but with further consequences that cannot be foreseen. In this case, spin actually conveys the message more vividly, through an appeal to feeling (seeing the numbers changing creates a sense of unease and restlessness) and an implicit call to action, rather than a logical appreciation of the figures and their scientific implications.