i. “We cease loving ourselves if no one loves us.” (On cesse de s’aimer si quelqu’un ne nous aime – Madame de Staël)
ii. “It seems to me that life’s circumstances, being ephemeral, teach us less about durable truths than the fictions based on those truths; and that the best lessons […] are to be found in novels where the feelings are so naturally portrayed that you fancy you are witnessing real life as you read.” (Madame de Staël)
iii. “The voice of conscience is so delicate that it is easy to stifle it; but it is also so clear that it is impossible to mistake it.” (-ll-)
iv. “Had this conversation last night while out with female friend:
Her: “What happened to all the nice, normal, intelligent guys?”
Me: “They are all at home right now, reading on their couches.”
Her: “Yeah, that sounds like what the man of my dreams would do.”
Yeah, doesn’t exactly lend itself to these people meeting.” (link. So they don’t. And the coordination problem is only exacerbated by the fact that such a male may be likely to also prefer a partner who’d rather stay at home reading.)
v. “I have now come to the conclusion never again to think of marrying, and for this reason; I can never be satisfied with anyone who would be blockhead enough to have me.” (Abraham Lincoln – from a letter to Mrs. Orville H. Browning (1 April 1838). Of course he later changed his mind.)
vi. “I believe it is an established maxim in morals that he who makes an assertion without knowing whether it is true or false, is guilty of falsehood; and the accidental truth of the assertion, does not justify or excuse him.” (Abraham Lincoln. Here’s a related link.)
vii. “In this sad world of ours, sorrow comes to all; and, to the young, it comes with bitterest agony, because it takes them unawares. The older have learned to ever expect it.” (-ll-)
viii. “Truth is generally the best vindication against slander.” (-ll-)
ix. “I do not like that man. I must get to know him better.” (-ll-)
x. “Wherever slavery is, it has been first introduced without law. The oldest laws we find concerning it, are not laws introducing it; but regulating it, as an already existing thing.” (-ll-)
xi. “I consider as lovers of books not those who keep their books hidden in their store-chests and never handle them, but those who, by nightly as well as daily use thumb them, batter them, wear them out, who fill out all the margins with annotations of many kinds, and who prefer the marks of a fault they have erased to a neat copy full of faults.” (Desiderius Erasmus)
xii. “A constant element of enjoyment must be mingled with our studies, so that we think of learning as a game rather than a form of drudgery, for no activity can be continued for long if it does not to some extent afford pleasure to the participant.” (-ll-)
xiii. “Do not be guilty of possessing a library of learned books while lacking learning yourself.” (-ll-)
xiv. “Some people are so fond of ill-luck that they run half-way to meet it.” (Douglas William Jerrold)
xv. “I have often been asked to be fair and view a matter from all sides. I did so, hoping something might improve if I viewed all sides of it. But the result was the same. So I went back to viewing things only from one side, which saves me a lot of work and disappointment. For it is comforting to regard something as bad and be able use one’s prejudice as an excuse.” (Karl Kraus)
xvi. “It is better not to express what one means than to express what one does not mean.” (-ll-)
xvii. “A “seducer” who boasts of initiating women into the mystery of love is like a stranger who arrives at a railroad station and offers to show the sights to a tourist guide.” (-ll-)
xviii. “Life is an effort that deserves a better cause.” (-ll-)
xix. “The world’s great men have not commonly been great scholars, nor its great scholars great men.” (Oliver Wendell Holmes, Sr.)
xx. “There is no passion that steals into the heart more imperceptibly and covers itself under more disguises than pride.” (Joseph Addison)
I finished the book – I didn’t expect to do that quite so soon, which is why I ended up posting two posts about the book during the same day. As Miao pointed out in her comment a newer version of the book exists, so if my posts have made you curious you should probably give that one a shot instead; this is a good book, but sometimes you can tell it wasn’t exactly written yesterday.
This book may tell you a lot of stuff you already know, especially if you have a little knowledge about biological systems, the human body, or perhaps basic statistics. I considered big parts of some chapters to be review stuff I already knew; I’d have preferred a slightly more detailed and in-depth treatment of the material. I didn’t need to be reminded how the kidneys work or that there’s such a thing as a blood-brain barrier, the stats stuff was of course old hat to me, I’m familiar with the linear no-threshold model, and there’s a lot of stuff about carcinogens in Mukherjee not covered in this book…
So it may tell you a lot of stuff you already know. But it will also tell you a lot of new stuff. I learned quite a bit and I liked reading the book, even the parts I probably didn’t really ‘need’ to read. I gave it 3 stars on account of the ‘written two decades ago’-thing and the ‘I don’t think I’m part of the core target group’-thing – but if current me had read it in the year 2000 I’d probably have given it four stars.
I don’t really know if the newer edition of the book is better than the one I read, and it’s dangerous to make assumptions about these things, but if he hasn’t updated it at all it’s still a good book, and if he has updated the material the new version is in all likelihood even better than the one I read. If you’re interested in this stuff, I don’t think this is a bad place to start.
I found out while writing the first post about the book that quoting from the book is quite bothersome. I’m lazy, so I decided to limit coverage here to some links which I’ve posted below – the stuff I link to is either covered or related to stuff that is covered in the book. It was a lot easier for me to post these links than to quote from the book in part because I visited many of these articles along the way while reading the book:
Polycyclic aromatic hydrocarbon.
Acceptable daily intake.
Linear Low dose Extrapolation for Cancer Risk Assessments: Sources of Uncertainty and How They Affect the Precision of Risk Estimates (short paper)
Do note that these links taken together can be somewhat misleading – as you could hopefully tell from the quotes in the first post, the book is quite systematic and the main focus is on basic/key concepts. To the extent that specific poisons like paraquat and DDT are mentioned in the book they’re used to ‘zoom in’ on a certain aspect in order to illustrate a specific feature, or perhaps in order to point out an important distinction – stuff like that.
So what is this book about? The introductory remarks below from the preface provide part of the answer:
“A word about organization of topics […] First, it is important to understand what we mean when we talk about ‘chemicals’. Many people think the term refers only to generally noxious materials that are manufactored in industrial swamps, frequently for no good purpose. The existence of such an image impedes understanding of toxicology and needs to be corrected. Moreover, because the molecular architecture of chemicals is a determinant of their behaviour in biological systems, it is important to create a little understanding of the principles of chemical structure and behavior. For these reasons, we begin with a brief review of some fundamentals of chemistry.
The two ultimate sources of chemicals – nature and industrial and laboratory synthesis – are then briefly described. This review sets the stage for a discussion of how human beings become exposed to chemicals. The conditions of human exposure are a critical determinant of whether and how a chemical will produce injury or disease, so the discussion of chemical sources and exposures naturally leads to the major subject of the book – the science of toxicology.
The major subjects of the last third of this volume are risk assessment […] and risk control, or management, and the associated topic of public perceptions of risk in relation to the judgments of experts.”
What can I say? – it made sense to read a toxicology textbook in between the Christie novels… The book was written in the 90s, but there are a lot of key principles and -concepts covered here that probably don’t have a much better description now than they did when the book was written. I wanted the overview and the book has delivered so far – I like it. Here’s some more stuff from the first half of the book:
“the greatest sources of chemicals to which we are regularly and directly exposed are the natural components of the plants and animals we consume as foods. In terms of both numbers and structural variations, no other chemical sources matches food. We have no firm estimate of the number of such chemicals we are exposed to through food, but it is surely immense. A cup of coffee contains, for example, nearly 200 different organic chemicals – natural components of the coffee bean that are extracted into water. Some impart color, some taste, some aroma, others none of the above. The simple potato has about 100 different natural components …” […]
“These facts bring out one of the most important concepts in toxicology: all chemicals are toxic under some conditions of exposure. What the toxicologist would like to know are those conditions. Once they are known, measures can be taken to limit human exposures so that toxicity can be avoided.” […]
The route of exposure refers to the way the chemical moves from the exposure medium into the body. For chemicals in the environment the three major routes are ingestion (the oral route), inhalation, and skin contact (or dermal contact). […]
The typical dose units are […] milligram of chemical per kilogram of body weight per day (mg/kg b.w./day). […] For the same intake […] the lighter person receives the greater dose. […] Duration of exposure as well as the dose received […] needs to be included in the equation […] dose and its duration are the critical determinants of the potential for toxicity. Exposure creates the dose.” […]
Analytical chemistry has undergone extraordinary advances over the past two to three decades. Chemists are able to measure many chemicals at the part-per-billion level which in the 1960s could be measured only at the part-per-million level […] or even the part-per-thousand level. […] These advances in detection capabilities have revealed that industrial chemicals are more widespread in the environment than might have been guessed 10 or 20 years ago, simply because chemists are now capable of measuring concentrations that could not be detected with analytical technology available in the 1960s. This trend will no doubt continue …” […]
“The nature of toxic damage produced by a chemical, the part of the body where that damage occurs, the severity of the damage, and the likelihood that the damage can be reversed, all depend upon the processes of absorption, distribution, metabolism and excretion, ADME for short. The combined effects of these processes determine the concentration a particular chemical […] will achieve in various tissues and cells of the body and the duration of time it spends there. Chemical form, concentration, and duration in turn determine the nature and extent of injury produced. Injury produced after absorption is referred to as systemic toxicity, to contrast it with local toxicity.” […]
“Care must be taken to distinguish subchronic or chronic exposures from subchronic or chronic effects. By the latter, toxicologists generally refer to some adverse effect that does not appear immediately after exposure begins but only after a delay; sometimes the effect may not be observed until near the end of a lifetime, even when exposure begins early in life (cancers, for example, are generally in this category of chronic effects). But the production of chronic effects may or may not require chronic exposure. For some chemicals acute or subchronic exposures may be all that is needed to produce a chronic toxicity; the effect is a delayed one. For others chronic exposure may be required to create chronic toxicity.” […]
“In the final analysis we are interested not in toxicity, but rather in risk. By risk is meant the likelihood, or probability, that the toxic properties of a chemical will be produced in populations of individuals under their actual conditions of exposure. To evaluate the risk of toxicity occurring for a specific chemical at least three types of information are requred:
1) The types of toxicity the chemical can produce (its targets and the forms of injury they incur).
2) The conditions of exposure (dose and duration) under which the chemical’s toxicity can be produced.
3) The conditions (dose, timing and duration) under which the population of people whose risk is being evaluated is or could be exposed to the chemical.
It is not sufficient to understand any one or two of these; no useful statement about risk can be made unless all three are understood.” […]
“It is rare that any single epidemiology study provides sufficiently definitive information to allow scientists to conclude that a cause-effect relationship exists between a chemical exposure and a human disease. Instead epidemiologists search for certain patterns. Does there seem to be a consistent association between the occurence of excess rates of a certain condition (lung cancer, for example) and certain exposures (e.g. to cigarette smoke) in several epidemiology studies involving different populations of people? If a consistent pattern of associations is seen, and other criteria are satisfied, causality can be established with reasonable certainty. […] Epidemiology studies are, of course, only useful after exposure has occurred. For certain classes of toxic agents, carcinogens being the most notable, exposure may have to take place for several decades before the effect, if it exists, is observable […] The obvious point is that epidemiology studies can not be used to identify toxic properties prior to the introduction of the chemical into commerce. This is one reason toxicologists turn to the laboratory. […] “The ‘nuts and bolts’ of animal testing, and the problems of test interpretation and extrapolation of results to human beings, comprise one of the central areas of controversy in the field of chemical risk assessment.” […]
Toxicologists classify hepatic toxicants according to the type of injuries they produce. Some cause accumulation of excessive and potentially dangerous amounts of lipids (fats). Others can kill liver cells; they cause cell necrosis. Cholestasis, which is decreased secretion of bile leading to jaundice […] can be produced as side effects of several therapeutic agents. Cirrhosis, a chronic change characterized by the deposition of connective tissue fibers, can be brought about after chronic exposure to several substances. […] ‘hepatotoxicity’ is not a very helpful term, because it fails to convey the fact that several quite distinct types of hepatic injury can be induced by chemical exposures and that, for each, different underlying mechanisms are at work. In fact, this situation exists for all targets, not only the liver.”
Lord Edgware dies is the first of the Christie books I’ve read where I was not really surprised. There were a few details which were very hard for me to figure out and I got one somewhat important thing wrong, but who had done it and the main part of the ‘how’ I’d figured out on my own. As for when I’d figured it out and as for the why, I’d rather not say anything about this in order not to spoil the mystery. But at least when it comes to this Christie novel I should make a point of emphasizing that you can figure out most of what happened here if you think carefully about the evidence – even I could do that, and I’m sure many of my readers are much smarter and much better at this kind of stuff than I am.
In The Murder on the Links I settled for an, I thought quite brilliant-, explanation of the facts early on which seemed to fit the facts exceedingly well – and the explanation also fit with things that happened later on as well. Unfortunately that explanation turned out to be utterly wrong. In a way I’m actually both a bit surprised and perhaps also a little disappointed that Christie did not consider that the facts she presents in her work could be interpreted the way I did – I’m hardly a that original thinker, and there’s no indication anywhere that this line of reasoning was even considered by Christie (/Poirot). I actually considered the fact that Poirot didn’t even mention this possibility as evidence in its favour along the way; it was the kind of hypothesis which, if true, he’d only reveal close to the end of the story – and then he’d talk about how this crucial insight had affected his interpretation of the other events. However it should be pointed out that the story is brilliant even if you get the wrong idea I did (…or some other wrong idea), and you’re probably in for a few surprises either way. These are both great books.
I’ve spent the last few days at my parents’ place and haven’t had much time for blogging due to social obligations. I read The Murder on the Links the day before yesterday and I’ll finish Lord Edgware Dies later today – I’ll probably blog the books tomorrow. For now I’ll just post a few Cochrane reviews and a couple of links:
i. Abstinence-only programs for preventing HIV infection in high-income countries (as defined by the World Bank). (link to the full paper here)
“Abstinence-only programs are widespread and well-funded, particularly in the United States and countries supported by the US President’s Emergency Plan for AIDS Relief. On the premise that sexual abstinence is the best and only way to prevent HIV, abstinence-only interventions aim to prevent, stop, or decrease sexual activity. These programs differ from abstinence-plus designs: abstinence-plus programs promote safer-sex strategies (e.g., condom use) along with sexual abstinence, but abstinence-only programs do not, and instead often highlight the limitations of condom use. An up-to-date review suggests that abstinence-only programs do not affect HIV risk in low-income countries; this review examined the evidence in high-income countries.
This review included thirteen randomized controlled trials comparing abstinence-only programs to various control groups (e.g., “usual care,” no intervention). Although we conducted an extensive international search for trials, all included studies enrolled youth in the US (total baseline enrollment=15,940 participants). Programs were conducted in schools, community centers, and family homes; all were delivered in family units or groups of young people. We could not conduct a meta-analysis because of missing data and variation in program designs. However, findings from the individual trials were remarkably consistent.
Overall, the trials did not indicate that abstinence-only programs can reduce HIV risk as indicated by behavioral outcomes (e.g., unprotected vaginal sex) or biological outcomes (e.g., sexually transmitted infection). Instead, the programs consistently had no effect on participants’ incidence of unprotected vaginal sex, frequency of vaginal sex, number of sex partners, sexual initiation, or condom use.”
The short version:
“Apart from providing counselling and drug treatment, strategies that reduce or cover the costs of accessing or providing these treatments could help smokers quit.
We found eleven trials, eight of which involve financial interventions directed at smokers and three of which involve financial interventions directed at healthcare providers.
Covering all the costs of smoking cessation treatment for smokers when compared to providing no financial benefits increased the proportion of smokers attempting to quit, using smoking cessation treatments, and succeeding in quitting. Although the absolute differences in quitting were small, the costs per person successfully quitting were low or moderate. Financial incentives directed at healthcare providers did not have an effect on smoking cessation.”
From the paper:
“Summary of main results:
With very high to modest levels of consistency, we detected a statistically significant positive effect of full financial interventions targeting smokers with regard to abstinence from smoking compared to provision of no financial intervention at six months follow-up or more (all abstinence measures: RR 2.45, 95% CI 1.17 to 5.12). The effect of full financial interventions was also extended to favourable outcomes on the use of smoking cessation treatments: the pooled effect of full coverage compared with no financial intervention on the use of smoking cessation treatments was highly significant for each treatment type (NRT, bupropion, and behavioural interventions).Despite the observation of multiple favourable effects of full as compared to no financial intervention, when full coverage was compared to partial coverage, results showed no significant effect on smoking cessation or quit attempts. […]
Five studies presented data on cost effectiveness. When full benefit was compared with partial or no benefit, the costs per quitter ranged from $119 to $6,450. [the $6,450 estimate is an outlier in that group; the other estimates are all much lower, at or below $1500/quitter – US] […]
In this review, covering the full cost to smokers of using smoking cessation treatment increased the number of successful quitters, the number of participants making a quit attempt, and the use of smoking cessation treatment when compared with no financial coverage. As the majority of the studies were rated at high or unclear risk of bias in three or more domains, and there was variation between the settings, interventions and participants of the included studies, the results should be interpreted cautiously. The differences in self-reported abstinence rate, number of participants making a quit attempt and use of smoking cessation treatments were modest.”
“Deliberate self-harm is a major health problem associated with considerable risk of subsequent self-harm, including completed suicide. This systematic review evaluated the effectiveness of various treatments for deliberate self-harm patients in terms of prevention of further suicidal behaviour. […]
A total of 23 trials were identified in which repetition of deliberate self-harm was reported as an outcome variable. The trials were classified into 11 categories. The summary odds ratio indicated a trend towards reduced repetition of deliberate self-harm for problem-solving therapy compared with standard aftercare (0.70; 0.45 to 1.11) and for provision of an emergency contact card in addition to standard care compared with standard aftercare alone (0.45; 0.19 to 1.07). The summary odds ratio for trials of intensive aftercare plus outreach compared with standard aftercare was 0.83 (0.61 to 1.14), and for antidepressant treatment compared with placebo was 0.83 (0.47 to 1.48). […]
There still remains considerable uncertainty about which forms of psychosocial and physical treatments of self-harm patients are most effective, inclusion of insufficient numbers of patients in trials being the main limiting factor. There is a need for larger trials of treatments associated with trends towards reduced rates of repetition of deliberate self-harm. The results of small single trials which have been associated with statistically significant reductions in repetition must be interpreted with caution and it is desirable that such trials are also replicated.”
A few other links which are not from the Cochrane site:
v. Errors in DCP2 cost-effectiveness estimate for deworming.”Over the past few months, GiveWell has undertaken an in-depth investigation of the cost-effectiveness of deworming, a treatment for parasitic worms that are very common in some parts of the developing world. While our investigation is ongoing, we now believe that one of the key cost-effectiveness estimates for deworming is flawed, and contains several errors that overstate the cost-effectiveness of deworming by a factor of about 100. This finding has implications not just for deworming, but for cost-effectiveness analysis in general: we are now rethinking how we use published cost-effectiveness estimates for which the full calculations and methods are not public. […]we see this case as a general argument for expecting transparency, rather than taking recommendations on trust – no matter how pedigreed the people making the recommendations. Note that the DCP2 was published by the Disease Control Priorities Project, a joint enterprise of The World Bank, the National Institutes of Health, the World Health Organization, and the Population Reference Bureau, which was funded primarily by a $3.5 million grant from the Gates Foundation. The DCP2 chapter on helminth infections, which contains the $3.41/DALY estimate, has 18 authors, including many of the world’s foremost experts on soil-transmitted helminths.”
vi. Evolution, Creationism, Intelligent Design – a Gallup poll from last year. According to that poll a majority of Americans (56%) think creationism should be taught in public school science classes. One of the questions asked were: If the public schools in your community taught the theory of evolution, — that is, the idea that human beings evolved from other species of animals — would you be upset, or not? A third of the people asked (34%) answered yes to this question. Incidentally in related news it should be noted that in a recent poll of South Korean biology teachers, 40% of them “agreed with the statement that “much of the scientific community doubts if evolution occurs”; and half disagreed that “modern humans are the product of evolutionary processes”.”
In slightly related news, according to an older poll conducted shortly before the turn of the century roughly one in five Americans asked back then didn’t know that the Earth revolves around the Sun. Other countries didn’t do any better:
“Gallup also asked the following basic science question, which has been used to indicate the level of public knowledge in two European countries in recent years: “As far as you know, does the earth revolve around the sun or does the sun revolve around the earth?” In the new poll, about four out of five Americans (79%) correctly respond that the earth revolves around the sun, while 18% say it is the other way around. These results are comparable to those found in Germany when a similar question was asked there in 1996; in response to that poll, 74% of Germans gave the correct answer, while 16% thought the sun revolved around the earth, and 10% said they didn’t know. When the question was asked in Great Britain that same year, 67% answered correctly, 19% answered incorrectly, and 14% didn’t know.”
You do have a potential ‘this is a silly question so I want to mess with the people asking it’-effect lurking in the background, but that’s probably mostly related to people giving the wrong answer deliberately. But even if many of the people asked perhaps gave the wrong answer deliberately, there’s still a substantial number of people answering that they ‘don’t know.’ I found the numbers surprising and I would love to see some updated estimates; a brief googling didn’t turn up anything.
This is the first novel featuring Hercule Poirot. I enjoyed it. You won’t be able to figure out everything before the end – I’d argue that there’s simply no way you can establish the true course of all events yourself, because you need to know stuff you cannot possibly be expected to know. Some crime stories are like that; I usually don’t particularly mind, but I found it just a little annoying this time because I spent more time while reading this book thinking about who might have done it, what had actually happened, who were lying about what, what had happened when, etc., than I did when I read the first couple of Christie books. But it’s not a big problem, and I should note that the added effort did mean that I got quite a few things right (or at least they were options I’d seriously considered). Some of the developments would probably have surprised me greatly if I’d read the book less carefully – I was still surprised a few times, but you’re supposed to be when reading a story like this. All the pieces of the puzzle fall into place at the end, which is more important to me than is the question of whether it’s possible to ‘crack the case’ on your own – some of the ‘suspicious behaviours’ you encounter have quite plausible explanations, and if you think about matters along the way some of these explanations will occur to you as well.
Overall an enjoyable read. I gave it 4 stars on goodreads, where the average rating is 3.94.
Most of the studies included in the book come from an area of research filled with shoddy science [#1 in the link], for example in one chapter he talks a lot about the bystander effect which is discussed in detail using the Genovese case as an illustration – he never even mentions (/doesn’t know? People hadn’t figured out yet that..?) that there weren’t actually 38 witnesses, etc. When reading the beginning of chapter 6 I was immediately reminded of this. I don’t trust a lot of the inferences made – they make for good stories, but often there are other ways to explain what happened besides the ones the author uses, and the examples are far from always convincing. If you base your inferences on shaky research then you can easily get into trouble, and he’s completely uncritical of the research he’s using in the book – nowhere in the main text does he even suggest the option that perhaps ‘in this particular study the sample size was quite low, and so perhaps we cannot trust the results of this experiment’. There are sometimes a few critical remarks in the notes, but these are also few and far between. He seems quite ignorant about some of the things he writes about; for example he talks about the bait-and-switch tactic at one point (without ever mentioning that that’s what it’s called), and it’s obvious in his treatment that he’s only familiar with it through personal experiences – he seems completely unaware that the tactic he describes actually is well-known and has a name. The same can be said of his treatment of loss aversion in the last chapter – he talks about this stuff, but seems to be completely oblivious to the fact that this psychological mechanism has a name and had been known for decades in the literature (the book is from 2003, and Kahneman & Tversky published a paper about this stuff already in 1984). He also talks about the winner’s curse in the last chapter without ever using that term, presumably because he’s again ignorant of the terminology and theory. There are generally a lot of text and words and not a lot of information; there was very little new stuff in the book, and most of the stuff he covers has in my opinion been handled better elsewhere (a marketing course I took a long time ago I’d say handled many of these things better, and I say that even though I didn’t like that course). He repeats himself quite a bit along the way.
I didn’t read every word of this book, a few times I skipped whole paragraphs because I knew what would be in them and I knew actually reading the words would be a waste of my time – this is very unlike me, I almost always read everything. I’m baffled that the book has such a high average rating on goodreads – I gave it a 2 star rating, whereas the average is 4.14. I should note that that goodreads rating was an important part of why I read it in the first place, so it’s been a disappointing read; I expected a lot more than I got. It does have redeeming features and I found the child-rearing remarks in chapter 3 in particular quite interesting, but although it’s far from horrible, it’s also simply not very good. I would not recommend this.
(No, not that type of modelling! – I was rather thinking about the type below…)
Anyway, I assume not all readers are equally familiar with this stuff, which I’ve incidentally written about before e.g. here. Some of you will know all this stuff already and you do not need to read on (well, maybe you do – in order to realize that you do not..). Some of it is recap, some of it I don’t think I’ve written about before. Anyway.
i. So, a model is a representation of the world. It’s a simplified version of it, which helps us think about the matters at hand.
ii. Models always have a lot of assumptions. A perhaps surprising observation is that, from a certain point of view, models which might be categorized as more ‘simple’ (few explicit assumptions) can be said to make as many assumptions as do more ‘complex’ models (many explicit assumptions); it’s just that the underlying assumptions are different. To illustate this, let’s have a look at two different models, model 1 and model 2. Model 1 is a model which states that ‘Y = aX’. Model 2 is a model which states that ‘Y = aX + bZ’.
Model 1 assumes b is equal to 0 so that Z is not a relevant variable to include, whereas model 2 assumes b is not zero – but both models make assumptions about this variable ‘Z’ (and the parameter ‘b’). Models will often differ along such lines, making different assumptions about variables and how they interact (incidentally here we’re implicitly assuming in both models that X and Z are independent). A ‘simple’ model does make fewer (explicit) assumptions about the world than does a ‘complex’ model – but that question is different from the question of which restrictions the two models impose on the data. And thinking in binary terms when we ask ourselves the question, ‘Are we making an assumption about this variable or this relationship?’, then the answer will always be ‘yes’ either way. Does the variable Z contribute information relevant to Y? Does it interact with other variables in the model? Both the simple model and the complex model include assumptions about this stuff. At every branching point where the complex model departs from the simple one, you have one assumption in one model (‘the distinction between f and g matters’, ‘alpha is non-zero’) and another assumption in the other (‘the distinction between f and g doesn’t matter’, ‘alpha is zero’). You always make assumptions, it’s just that the assumptions are different. In simple models assumptions are often not spelled out, which is presumably part of why some of the assumptions made in such models are easy to overlook; it makes sense that they’re not, incidentally, because there’s an infinite number of ways to make adjustments to a model. It’s true that branching out does take place in some complex models in ways that do not occur in simple models, and once you’re more than one branching point away from the departure point where the two models first differ then the behaviour of the complex model may start to be determined by additional new assumptions where on the other hand the behaviour of the simple model might still rely on the same assumption that determined the behaviour at the first departure point – so the number of explicit assumptions will be different, but an assumption is made in either case at every junction.
As might be inferred from the comments above usually ‘the simple model’ will be the one with the more restrictive assumptions, in terms of what the data is ‘allowed’ to do. Fewer assumptions usually means stronger assumptions. It’s a much stronger assumption to assume that e.g. males and females are identical than is the alternative that they are not; there are many ways they could be not identical but only one way in which they can be. The restrictiveness of a model does not equal the number of assumptions (explicitly) made. No, on a general note it is rather the case that more assumptions mean that your model becomes less restrictive, because additional assumptions allow for more stuff to vary – this is indeed a big part of why model-builders generally don’t just stick to very simple models; if you do that, you don’t get the details right. Adding more assumptions may allow you to make a more correct model that better explains the data. It is my experience (not that I have much of it, but..) that people who’re unfamiliar with modelling think of additional assumptions as somehow ‘problematic’ – ‘more stuff can go wrong if you add more assumptions, the more assumptions you have the more likely it is that one of them is violated’. The problem is that not making assumptions is not really an option; you’ll basically assume something no matter what you do. ‘That variable/distinction/connection is irrelevant’, which is often the default assumption, is also just that – an assumption. If you do modelling you don’t ever get to not make assumptions, they’re always there lurking in the background whether you like it or not.
iii. A big problem is that we don’t know a priori which assumptions are correct before we’ve actually tested the models – indeed, we often make models mainly in order to figure out which assumptions are correct. (Sometimes we can’t even test the assumptions we’re making in a model, but let’s ignore this problem here…). A more complex model may not always be more correct, perform better. Sometimes it’ll actually do a worse job at explaining the variation in the data than a simple one would have done. When you add more variables to a model, you also add more uncertainty because of things like measurement error. Sometimes it’s worth it, because the new variable explain a lot of the variation in the data. Sometimes it’s not – sometimes the noise you add is far more relevant than is the additional information contribution about how the data behaves.
There are various ways to try to figure out if the amount of noise added from an additional variable is too high for it to be a good idea to include the variable in a model, but they’re not perfect and you always have tradeoffs. There are many different methods to estimate which model performs better, and the different methods apply different criteria – so you can easily get into a situation where the choice of which variable to include in your ‘best model’ depends on e.g. which information criterium you choose to apply.
Anyway the key point is this: You can’t just add everything (all possible variables you could imagine play a role) and assume you’ll be able to explain everything that way – adding another variable may indeed sometimes be a very bad idea.
iv. If you test a lot of hypotheses simultaneously, which all have some positive probability of being evaluated as correct, then as you add more variables to your model it becomes more and more likely that at least one of those hypotheses will be evaluated as being correct (relevant link) unless you somehow adjust the probability of a given hypothesis being evaluated as correct as you add more hypotheses along the way. This is another reason adding more variables to a model can sometimes be problematic. There are ways around this particular problem, but if they are not used, which they often are not, then you need to be careful.
v. Adding more variables is not always preferable, but then what about throwing more data at the problem by adding to the sample size? Surely if you add more data to the sample that should increase your confidence in the model results, right? Well… No – bigger is actually not always better. This is related to the concept of consistency in statistics. “A consistent estimator is one for which, when the estimate is considered as a random variable indexed by the number n of items in the data set, as n increases the estimates converge to the value that the estimator is designed to estimate,” as the wiki article puts it. You can imagine that consistency is one of the key assumptions underlying statistical models – it really is, we care a lot about consistency, and all else equal you should always prefer a consistent estimator to an inconsistent one (however it should be noted that all else is not always equal; a consistent estimator may have larger variance than an inconsistent estimator in a finite sample, which means that we may actually sometimes prefer the latter to the former in specific situations). But the thing is, not all estimators are consistent. There are always some critical assumptions which need to be satisfied in order for the consistency requirement to be met, and in a bad model these requirements will not be met. If you have a bad model, for example if you’ve incorrectly specified the relationships between the variables or included the wrong variables in your model, then increasing the sample size will do nothing to help you – additional data will not somehow magically make the estimates more reliable ‘because of asymptotics’. In fact if your model’s performance is very sensitive to the sample size to which you apply it, it may well indicate that there’s a problem with the model, i.e. that the model is misspecified (see e.g. this).
vi. Not all model assumptions are equal – some assumptions will usually be much more critical than others. As already mentioned consistency of regressors is very important, and here it is important to note that not all model assumption violations will lead to inconsistent estimators. An example of where this is not the case is the homoskedasticity assumption (see also this) in regression analysis. Here you can actually find yourself in a situation where you deliberately apply a model where you know that one of your assumptions about how the data behaves is violated, yet this is not a problem at all because you can deal with the problem separately so that that violation is of no practical importance as you can correct for it. As already mentioned in the beginning most models will be simplified versions of the stuff that goes on in the real world, so you’ll expect to see some ‘violations’ here and there – the key question to ask here is then, is the violation important and which consequences does it have for the estimates we’ve obtained? If you do not ask yourself such questions when evaluating a model, you may easily end up quibbling about details which are of no importance anyway because they don’t really matter. And remember that all the assumptions made in the model are not always spelled out, and that some of the important ones may have been overlooked.
vii. Which causal inferences to make from the model? Correlation != causation. To some extent the question to which extent the statistical link is causal relates to questions pertaining to whether we’ve picked the right variables and the right way to relate them to each other. But as I’ve remarked upon before some model types are better suited for establishing causal links than are others – there are good ways and bad ways to get at the heart of the matter (one application here, I believe I’ve linked to this before). Different fields will often have developed different approaches, see e.g. this, this and this. Correlation on its own will probably tell you next to nothing about anything you might be interested in; as I believe my stats prof put it last semester, ‘we don’t care about correlation, correlation means nothing’. Randomization schemes with treatment groups and control groups are great. If we can’t do those, we can still try to make models to get around the problems. Those models make assumptions, but so do the other models you’re comparing them with and in order to properly evaluate them you need to be explicit about the assumptions made by the competing models as well.
This book is a crime novel where we sort of know ‘who did it’, but we know more about the ‘who’-part than about the ‘it’-part. I have done everything I could to avoid spoilers in the remarks below. I decided to give it four stars on goodreads – the average rating there is 3.84. I decided to crosspost my goodreads review of the book here as well:
“The plot is very interesting and quite clever, but the writing isn’t anything special and at times you can sort of tell that it’s a translation you’re reading (which is not a good thing).
A thing that really annoyed me about the book while I was reading it was the thought that there was a better option, with a much lower associated risk. The way the main character(s) decide to approach the problem is suboptimal from the outset – it was not the best way to proceed, and that strains the willing suspense of disbelief. This, plus the fact that a few of the other decisions made by the main characters along the way are borderline implausible even taking the setting in question for granted, and the unimpressive language, is why an otherwise quite brilliant page-turner of a book in my opinion still falls short of the five star evaluation.
All that said, it is a pretty damn good book. But…”
It’s very hard to convey the reasons why I’m not ‘completely satisfied’ with the stuff in the book without adding way too much information about the plot, and I am being deliberately vague in the review above. Remember that one main reason why I’m being vague is that I don’t want to spoil the book, and I take care not to do this because I think it’s a good book that people should read if they like that kind of stuff. I liked it a lot, it’s a compelling story which is hard to put away (I started reading it late last evening, which was a mistake because I found it hard to stop and so got to sleep only much later than I’d planned).
As I also pointed out in the comments, I’ve completed And Then There Were None (you can read my brief review of the book here), but it’s not easy to say much about that book without providing spoilers so instead I decided to blog the book mentioned in the post title.
It’s not easy to blog the other book either, so I won’t say very much about it. I’ve only read roughly the first three chapters (out of eight) but reading it requires absolute concentration and focus, which makes it feel suspiciously much like actual work. It’s quite technical, here’s the description of the book from goodreads:
“This book starts with the basic concepts of Fuzzy Logic: the membership function, the intersection and the union of fuzzy sets, fuzzy numbers, and the extension principle underlying the algorithmic operations. Several chapters are devoted to applications of Fuzzy Logic in Operations Research: PERT planning with uncertain activity durations, Multi-Criteria Decision Analysis (MCDA) with vague preferential statements, and Multi-Objective Optimization (MOO) with weighted degrees of satisfaction. New items are: Fuzzy PERT using activity durations with triangular membership functions, Fuzzy SMART with a sensitivity analysis based upon Fuzzy Logic, the Additive and the Multiplicative AHP with a similar feature, ELECTRE using the ideas of the AHP and SMART, and a comparative study of the ideal-point methods for MOO. Finally, earlier studies of colour perception illustrate the attempts to find a physiological basis for the set-theoretical and the algorithmic operations in Fuzzy Logic. The last chapter also discusses some key issues in linguistic categorization and the prospects of Fuzzy Logic as a multi-disciplinary research activity. Audience: Researchers and students working in applied mathematics, operations research, management science, business administration, econometrics, industrial engineering, information systems, artificial intelligence, mathematical psychology, and psycho-physics.”
A little bit of stuff from the book:
“The mathematical theory of fuzzy sets (Zadeh, 1965), alternatively referred to as fuzzy logic, is concerned with the degree of truth that the outcome belongs to a particular category, not with the degree of likelihood that the outcome will be observed. […] Fuzzy logic agrees that an element may with a positive degree of truth belong to a set and with another positive degree of truth to the complement of the set, whereby it violates the law of noncontradiction (a statement cannot be true and not-true at the same time). Fuzzy logic also violates the law of the excluded middle (a statement is either true or false, “tertium non datur “).”
(Fuzzy numbers are weird:)
“Let us consider the fuzzy number ã, that is, the fuzzy set of numbers which are roughly equal to the crisp number a. […] In general, a fuzzy number has a membership function which increases monotonically from o to 1 on the left-hand side; thereafter, there is a single top or a plateau at the level 1; and finally, the membership function decreases monotonically to 0 on the right-hand side. […] For practical purposes we shall further limit our attention to a convenient subclass of fuzzy numbers: to those with a triangular membership function. Such a fuzzy number ã is characterized by three parameters: the lower value a-1, the modal value a-m, and the upper value a-u. The interval (a-1, a-u) constitutes the basis of the triangle, and a-m is the position of the top. [slight change in notation due to wordpress formatting problems, US] […] we shall denote triangular fuzzy numbers as ordered triples, so that we simply write ã = (a-1, a-m, a-u) […]
In general, a triangular fuzzy number does not […] have a proper opposite number. […] In general, a triangular fuzzy number does not […] have a proper inverse. […] The maximum of two triangular fuzzy numbers is not necessarily triangular …”
Chapter 2 mostly deals with basic properties of fuzzy numbers and -sets, calculation rules, etc. In chapter 3 the ‘for planning and decision making’-part of the title enters the equation as well – this chapter deals with Stochastic and fuzzy PERT. You can probably read and understand most of the first couple of chapters without having much math/stats background knowledge, but here I assume it may start to get a little more difficult if you don’t. I don’t want to blog equations (formatting problems is a pain in the neck) but you should be able to get an impression of which type of book this is from the comments below anyway:
“In stochastic optimization it is generally very difficult, if not impossible, to calculate the probability distribution of an optimal solution. Therefore, stochastic optimization problems are sometimes converted into deterministic problems with optimal solutions which have a particular risk to be unfeasible and/or suboptimal (see Kall and Wallace, 1994). This mode of operation has the advantage that it supplies a deterministic schedule for action. The simplest procedure is to replace every stochastic quantity in the problem by its expectation. The literature on stochastic optimization, however, does not always recommend the user to do so because it is such a crude simplification: the deterministic solution may have a high chance to be unfeasible.” […]
“A stochastic optimization problem can also be converted into a deterministic problem under constraints which have a controlled chance to be violated. The PERT problem, for instance, can accordingly be written as [a] so-called chance-constrained programming problem […] the chance-constrained version of PERT can be rewritten as [a] linear programming problem […]
In summary, the simple and the extended versions of PERT are particular formulations of a stochastic optimization problem. The manner in which these versions are employed is unusual in the field of stochastic optimization, however, because the risk·of constraint violations is high. And indeed, PERT has not been designed to make a plan that can be followed throughout the duration of the project. In practice, frequent recalculations are necessary in order to review the plan in the light of what happens during the execution of the activities. […]
When the activity durations are modelled as fuzzy numbers we have several pragmatic approaches of fuzzy optimization at our disposal to make a time schedule …”
The edition I’m sitting with is from before the year 2000, and I assume that when it comes to some of the aspects covered the updated version of the book (there’s also a 2011 edition I believe) is better; a lot of stuff has happened in CS and related fields in the meantime, and presumably some of the approaches described which were back then considered computationally too expensive to use no longer are.
Despite the low page count (a couple hundred pages) this book is hard work, and it’s not a book you can just sit down and read in an afternoon. At least not if you want to actually learn something.
i. I’ve read The Murder of Roger Ackroyd. I’ll say very little about the book here because I don’t want to spoil it in any way – but I do want to say that the book is awesome. I read it in one sitting, and I gave it 5 stars on goodreads (av.: 4,09); I think it’s safe to say it’s one of the best crime novels I’ve ever read (and I’ll remind you again that even though I haven’t read that much crime fiction, I have read some – e.g. every Sherlock Holmes story ever published and every inspector Morse novel written by Colin Dexter). The cleverness of the plot reminded me of a few Asimov novels I read a long time ago. A short while after I’d finished the book I was in the laundry room about to start the washing machine and a big smile spread on my face, I was actually close to laughing – because damn, the book is just so clever, so brilliant!
I highly recommend the book.
ii. I have been watching a few of the videos in the Introduction to Higher Mathematics youtube-series by Bill Shillito, here are a couple of examples:
I’m not super impressed by these videos at this point, but I figured I might as well link to them anyway. There are 19 videos in the playlist.
iii. Mind the Gap: Disparity Between Research Funding and Costs of Care for Diabetic Foot Ulcers. A brief comment from this month’s issue of Diabetes Care. The main point:
“Diabetic foot ulceration (DFU) is a serious and prevalent complication of diabetes, ultimately affecting some 25% of those living with the disease (1). DFUs have a consistently negative impact on quality of life and productivity […] Patients with DFUs also have morbidity and mortality rates equivalent to aggressive forms of cancer (2). These ulcers remain an important risk factor for lower-extremity amputation as up to 85% of amputations are preceded by foot ulcers (6). It should therefore come as no surprise that some 33% of the $116 billion in direct costs generated by the treatment of diabetes and its complications was linked to the treatment of foot ulcers (7). Another study has suggested that 25–50% of the costs related to inpatient diabetes care may be directly related to DFUs (2). […] The cost of care of people with diabetic foot ulcers is 5.4 times higher in the year after the first ulcer episode than the cost of care of people with diabetes without foot ulcers (10). […]
We identified 22,531 NIH-funded projects in diabetes between 2002–2011. Remarkably, of these, only 33 (0.15%) were specific to DFUs. Likewise, these 22,531 NIH-funded projects yielded $7,161,363,871 in overall diabetes funding, and of this, only $11,851,468 (0.17%) was specific to DFUs. Thus, a 604-fold difference exists between overall diabetes funding and that allocated to DFUs. […] As DFUs are prevalent and have a negative impact on the quality of life of patients with diabetes, it would stand to reason that U.S. federal funding specifically for DFUs would be proportionate with this burden. Unfortunately, this yawning gap in funding (and commensurate development of a culture of sub-specialty research) stands in stark contrast to the outsized influence of DFUs on resource utilization within diabetes care. This disparity does not appear to be isolated to [the US].”
I’ve read about diabetic foot care before, but I had no idea about this stuff. Of the roughly 175.000 peer-reviewed publications about diabetes published in the period of 2000-2009, only 1200 of them – 0.69% – were about the diabetic foot. You can quibble over the cost estimates and argue that perhaps they’ve overstated because these guys want more money, but I think that it’s highly unlikely that the uncertainties related to the cost estimates are so big as to somehow make the current (research) ressource allocation scheme appear cost efficient in a CBA with reasonable assumptions – there simply has to be some low-hanging fruit here.
A slightly related (if you stretch the definition of ‘related’ a little) article which I also found interesting here.
iv. “How quickly would the ocean’s drain if a circular portal 10 meters in radius leading into space was created at the bottom of Challenger Deep, the deepest spot in the ocean? How would the Earth change as the water is being drained?”
And, “Supposing you did Drain the Oceans, and dumped the water on top of the Curiosity rover, how would Mars change as the water accumulated?”
v. Take news of cancer ‘breakthrough’ with a big grain of salt. I’d have added the word ‘any’ and probably an ‘s’ to the word breakthrough as well if I’d authored the headline, in order to make a more general point – but be that as it may… The main thrust:
“scientific breakthroughs should not be announced at press conferences using the vocabulary of public relations professionals.
The language of science and medicine should be cautious and humble because diseases like cancer are relentless and humbling. […]
The reality is that biomedical research is a slow process that yields small incremental results. If there is a lesson to retain from the tale of CFI-400945, it’s that finding new treatments takes a lot of time and a lot of money. It is a venture worthy of support, but unworthy of exaggerated expectations and casual overstatement.
Hype only serves to create false hope.”
People who’re not familiar with how science actually works (and how related processes such as drug development work) often have weird ideas about how fast things tend to proceed and how (/un?)likely a ‘promising’ result in the lab might be to be translated into, say, a new treatment option available to the general patient population. And yeah, that set of ‘people who’re not familiar with how science works’ would include almost everybody.
It should be noted, as I’m sure Picard knows, that it’s a lot easier to get funding for your project if you’re exaggerating benefits and downplaying costs; if you’re too optimistic; if you’re saying nice things about the guy writing the checks even though you think he’s an asshole; etc. Some types of dishonesty are probably best perceived of as nothing more than ‘good salesmanship’ whereas other types might have different interpretations; but either way it’d be silly to pretend that stuff like false hope does not sell a lot of tickets (and newspapers, and diluted soap water, and…). Given that, it’s hardly likely that things will change much anytime soon – the demand for information here is much higher than is the demand for accurate information. But it’s nice to read an article like this one every now and then anyway.
I blogged a quote from the first one, by W. K. Clifford, a while ago, but I recently decided to reread it. I have not covered the Peirce text at all before. If you were wondering how I came across those texts, I’ve recently been browsing Pojman’s Classics of Philosophy. Some quotes from the texts below – first the Clifford text:
“it is not possible […] to sever the belief from the action it suggests as to condemn the one without condemning the other. No man holding a strong belief on one side of a question, or even wishing to hold a strong belief on one side, can investigate it with such fairness and completeness as if he were really in doubt and unbiased; so that the existence of a belief not founded on fair inquiry unfits a man for the performance of this necessary duty.
Nor is that truly a belief at all which has not some influence upon the actions of him who holds it. […] No real belief, however trifling and fragmentary it may seem, is ever truly insignificant; it prepares us to receive more of its like, confirms those which resembled it before, and weakens others; and so gradually it lays a stealthy train in our inmost thoughts, which may some day explode into overt action, and leave its stamp upon our character for ever. […]
Habitual want of care about what I believe leads to habitual want of care in others about the truth of what is told to me. Men speak the truth of one another when each reveres the truth in his own mind and in the other’s mind; but how shall my friend revere the truth in my mind when I myself am careless about it, when I believe thing because I want to believe them, and because they are comforting and pleasant? […]
To sum up: it is wrong always, everywhere, and for anyone, to believe anything upon insufficient evidence.
If a man, holding a belief which he was taught in childhood or persuaded of afterwards, keeps down and pushes away any doubts which arise about it in his mind, purposely avoids the reading of books and the company of men that call into question or discuss it, and regards as impious those questions which cannot easily be asked without disturbing it — the life of that man is one long sin against mankind. […]
Inquiry into the evidence of a doctrine is not to be made once for all, and then taken as finally settled. It is never lawful to stifle a doubt; for either it can be honestly answered by means of the inquiry already made, or else it proves that the inquiry was not complete.
“But,” says one, “I am a busy man; I have no time for the long course of study which would be necessary to make me in any degree a competent judge of certain questions, or even able to understand the nature of the arguments.”
Then he should have no time to believe.”
I liked Clifford better than Peirce, so I shan’t quote too much from the latter (even though it’s significantly longer). However here’s a little stuff from the text:
“We generally know when we wish to ask a question and when we wish to pronounce a judgment, for there is a dissimilarity between the sensation of doubting and that of believing. […] Doubt is an uneasy and dissatisfied state from which we struggle to free ourselves and pass into the state of belief; while the latter is a calm and satisfactory state which we do not wish to avoid, or to change to a belief in anything else. On the contrary, we cling tenaciously, not merely to believing, but to believing just what we do believe.
Thus, both doubt and belief have positive effects upon us, though very different ones. Belief does not make us act at once, but puts us into such a condition that we shall behave in some certain way, when the occasion arises. Doubt has not the least such active effect, but stimulates us to inquiry until it is destroyed. […] the sole object of inquiry is the settlement of opinion. We may fancy that this is not enough for us, and that we seek, not merely an opinion, but a true opinion. But put this fancy to the test, and it proves groundless; for as soon as a firm belief is reached we are entirely satisfied, whether the belief be true or false. […] The most that can be maintained is, that we seek for a belief that we shall think to be true. But we think each one of our beliefs to be true, and, indeed, it is mere tautology to say so.” […]
“the instinctive dislike of an undecided state of mind, exaggerated into a vague dread of doubt, makes men cling spasmodically to the views they already take. The man feels that, if he only holds to his belief without wavering, it will be entirely satisfactory. Nor can it be denied that a steady and immovable faith yields great peace of mind. […] And in many cases it may very well be that the pleasure he derives from his calm faith overbalances any inconveniences resulting from its deceptive character.” […]
“above all, let it be considered that what is more wholesome than any particular belief is integrity of belief, and that to avoid looking into the support of any belief from a fear that it may turn out rotten is quite as immoral as it is disadvantageous. The person who confesses that there is such a thing as truth, which is distinguished from falsehood simply by this, that if acted on it should, on full consideration, carry us to the point we aim at and not astray, and then, though convinced of this, dares not know the truth and seeks to avoid it, is in a sorry state of mind indeed.”
Before I start out, a few random remarks about other matters: I ran 43 km last week, I’m in excellent shape at this point. I had a doctor’s appointment Tuesday where I was told that my Hba-1c was 6,9%, given the DCCT- HbA1c metric. The numbers look so good that the nurse decided against ordering a lipid panel for the next appointment, even though this is something you normally get done every year; she thought it would not be worth it and I agreed. When viewed from one angle I’m in very good health, yet from another angle it’s also so poor that I’d die without access to my medication. Oh well…
So anyway the reason why I wrote this post is that I have been thinking a little bit on and off about other people’s mental maps – that is to say, how they perceive the world. So for example, do other people see colour the same way I do? Given the existence of colourblind individuals we already know the answer to that one; at least some people perceive light in a different manner. Blind people would be another obvious example; they don’t perceive light at all (/or they are unable to interpret the light waves they do perceive). Of course there is also some variation when it comes to how people’s eyes refract light, some people suffer from myopia, some from presbyopia, etc. – so when other people see stuff, it’s far from obvious why the default assumption should be that they’re seeing the same thing you are. And why for that matter limit the analysis to humans – how do other living creatures perceive the world? As Dawkins points out in The Ancestor’s tale: “mammals in general probably have the poorest colour vision among vertebrates. Most mammals see colour, if at all, only as well as a colourblind man.” How different they must perceive the world! When I was a child I remember asking my father if (and if so, how?) the cat actually knew I was a living creature like itself – if/how it could deduce that the huge lump of cells which was much bigger than it was and which was moving around in various ways was actually one living thing, rather than a big ball of disjoint materials, a huge ball of fur or perhaps something else. I remember also thinking about whether it could tell I was me, rather than some other human walking around there and I tried to come up with a way to test this, without luck. I realized it could tell I was a living creature and I remember finding the thought that it actually could do these things fascinating; it was only later I realized that precisely abilities like these – like, say, the ability to tell the difference between one bunch of living cells and another, and the ability to tell the difference between a bunch of cells and other stuff which are not collections of cells – are extremely useful for living creatures and so it should not be surprising that the cat had evolved senses which could help it figuring out this kind of stuff. (Though perhaps some people would say that this observation should only if anything increase my fascination – I’m not sure if I disagree, I do try to be amazed…).
But vision is but one aspect of our mental map of what the world is like. What about stuff like sounds? Do other people hear and interpret soundwaves the same way you do? I’ve touched upon that one before. In general they probably don’t, at least not completely. There’s a lot of variation – some people are deaf, some people don’t hear very well, some people have excellent hearing; and some people are old and hear sounds of a high frequency much worse than you do; for example my grandmother’s hearing is so bad that without a hearing aid she probably can’t hear birds singing at all. A specific example most people probably are also familiar with is the way other people hear your voice vs the way you hear your own voice and believe you sound like when you talk – most people have, I assume, experienced hearing recordings of their own voices and then been surprised at how they actually sound like. Again the variation in how different organisms approach these things only increases when you include animals in the analysis.
One notion unrelated to sensory stuff which sometimes will surprise me is how other people can actually think about you and talk about you when you’re not around. This always seemed somewhat weird to me that people might do that. Part of why I feel that this is strange or weird is presumably that I don’t really ever think much about this – if I don’t think about it, they can’t be doing this stuff, right? (Wrong). Another factor is this: Why would anyone waste time talking about me, when there are so many other, more interesting, people or subjects around that they might talk about? In a way it’s a mental double standard of sorts to consider that weird and I’m aware of it – I know that I’ll sometimes talk about other people I know when engaged in conversation with others, so the idea that you can talk about other people that way is not unfamiliar to me and such behaviour is not unnatural and I do engage in it. So it’s not that I’m completely in the dark as to why people do it. But the thought that other people are doing this, that I might be one they talk about – that’s somehow a very strange notion to me. I am aware that for some people this is not a strange notion at all, but rather an aspect of human social interaction that they give a lot of thought; and I find this interesting. Some people will worry a lot about what others say about them when they’re not around, if they perhaps recently did something which might lead others to say bad things about them later, how to minimize this risk, etc. Some people are probably much more prone to this kind of thinking than are others; I assume there are gender differences early on (‘teenage boys threaten or beat up their enemies, teenage girls slander them..’), and cost-benefit aspects are also relevant to include here given the underlying coalition-forming and -building aspects – if it’s somehow important that the other person likes you for some reason, you’ll presumably worry more about this stuff and be more likely to engage in this type of thinking than you otherwise would. On a related note we think more about the people we care about than we do about the people we don’t, and so we’re probably also more likely to talk about the people we care about when engaging in conversations with others.
How you look matters when it comes to how other people behave towards you – for some people it matters a lot, for others it matters less. I find this interesting, that some people give this aspect much more attention than I do, because I so very rarely spare a thought about how I happen to look at any given point in time. I don’t have to look at myself much so I don’t really see why I should care how I look, except to the extent that other people care – and I’m aware part of the reason why I do not care is that I do not have much of a reason to care at this point; I rarely interact with other people in the real world, and I never interact with the people who might be the most interested in the way I look – viz. potential romantic partners. Incidentally it seems a reasonable assumption to me that when it comes to this aspect of people’s mental maps – romantic stuff – people who are in relationships think differently about other people in their social spheres than do people who are not. But I’ve never really given it much thought. It seems to be a commonly voiced complaint that males without a romantic partner are highly likely to approach females with this particular type of framework in mind – ‘a woman is a potential sexual partner until proven otherwise’ – whereas women are more likely (it is claimed) to perceive of a male using a different framework; is he a potential friend/ally/…? Anyway, looks is but one of many aspects; people’s mental maps are so different from each other that it’s presumably a very common experience to have people judging you based on criteria you consider to be irrelevant and do not give a moment’s thought. Just as it’s presumably a common experience to have people judging you harshly for the behaviours you consider to be amongst your most virtuous.
A thing that should make it easier to conceptualize how different the mental map of another individual may look like is to try to remember that the other person with whom you’re interacting is always the main character in his or her story.
i. Planetary habitability (featured).
“Planetary habitability is the measure of a planet‘s or a natural satellite‘s potential to develop and sustain life. Life may develop directly on a planet or satellite or be transferred to it from another body, a theoretical process known as panspermia. As the existence of life beyond Earth is currently uncertain, planetary habitability is largely an extrapolation of conditions on Earth and the characteristics of the Sun and Solar System which appear favourable to life’s flourishing—in particular those factors that have sustained complex, multicellular organisms and not just simpler, unicellular creatures. Research and theory in this regard is a component of planetary science and the emerging discipline of astrobiology.
An absolute requirement for life is an energy source, and the notion of planetary habitability implies that many other geophysical, geochemical, and astrophysical criteria must be met before an astronomical body can support life. In its astrobiology roadmap, NASA has defined the principal habitability criteria as “extended regions of liquid water, conditions favourable for the assembly of complex organic molecules, and energy sources to sustain metabolism.”
In determining the habitability potential of a body, studies focus on its bulk composition, orbital properties, atmosphere, and potential chemical interactions. Stellar characteristics of importance include mass and luminosity, stable variability, and high metallicity. Rocky, terrestrial-type planets and moons with the potential for Earth-like chemistry are a primary focus of astrobiological research, although more speculative habitability theories occasionally examine alternative biochemistries and other types of astronomical bodies.”
The article has a lot of stuff – if you’re the least bit interested (and if you are human and alive, as well as a complex enough lifeform to even conceptualize questions like these, why wouldn’t you be?) you should go have a look. When analyzing which factors might impact habitability of a system, some might say that we humans are rather constrained by our somewhat limited sample size of planetary systems known to support complex multicellular life, but this doesn’t mean we can’t say anything about this stuff. Even though extreme caution is naturally warranted when drawing conclusions here. Incidentally, although the Earth does support complex life now we would probably be well-advised to remember that this was not always the case, nor will it continue to be the case in the future – here’s one guess at what the Earth will look like in 7 billion years:
The image is from this article. Of course living organisms on Earth will be screwed long before this point is reached.
ii. Parity of zero (‘good article’).
Zero is an even number. Apparently a rather long wikipedia article can be written about this fact…
iii. 1907 Tiflis bank robbery (featured).
Not just any bank robbery – guns as well as bombs/grenades were used during the robbery, around 40 people died(!), and the list of names of the people behind the robbery includes the names Stalin and Lenin.
iv. Möbius Syndrome – what would your life be like if you were unable to make facial expressions and unable to move your eyes from side to side? If you want to know, you should ask these people. Or you could of course just start out by reading the article…
v. Book of the Dead (‘good article’).
“The Book of the Dead is an ancient Egyptian funerary text, used from the beginning of the New Kingdom (around 1550 BCE) to around 50 BCE. The original Egyptian name for the text, transliterated rw nw prt m hrw is translated as “Book of Coming Forth by Day”. Another translation would be “Book of emerging forth into the Light”. The text consists of a number of magic spells intended to assist a dead person’s journey through the Duat, or underworld, and into the afterlife.
The Book of the Dead was part of a tradition of funerary texts which includes the earlier Pyramid Texts and Coffin Texts, which were painted onto objects, not papyrus. Some of the spells included were drawn from these older works and date to the 3rd millennium BCE. Other spells were composed later in Egyptian history, dating to the Third Intermediate Period (11th to 7th centuries BCE). A number of the spells which made up the Book continued to be inscribed on tomb walls and sarcophagi, as had always been the spells from which they originated. The Book of the Dead was placed in the coffin or burial chamber of the deceased.
There was no single or canonical Book of the Dead. The surviving papyri contain a varying selection of religious and magical texts and vary considerably in their illustration. Some people seem to have commissioned their own copies of the Book of the Dead, perhaps choosing the spells they thought most vital in their own progression to the afterlife. […]
A Book of the Dead papyrus was produced to order by scribes. They were commissioned by people in preparation for their own funeral, or by the relatives of someone recently deceased. They were expensive items; one source gives the price of a Book of the Dead scroll as one deben of silver, perhaps half the annual pay of a labourer. Papyrus itself was evidently costly, as there are many instances of its re-use in everyday documents, creating palimpsests. In one case, a Book of the Dead was written on second-hand papyrus.
Most owners of the Book of the Dead were evidently part of the social elite; they were initially reserved for the royal family, but later papyri are found in the tombs of scribes, priests and officials. Most owners were men, and generally the vignettes included the owner’s wife as well. Towards the beginning of the history of the Book of the Dead, there are roughly 10 copies belonging to men for every one for a woman. However, during the Third Intermediate Period, 2/3 were for women; and women owned roughly a third of the hieratic paypri from the Late and Ptolemaic Periods.
The dimensions of a Book of the Dead could vary widely; the longest is 40m long while some are as short as 1m. They are composed of sheets of papyrus joined together, the individual papyri varying in width from 15 cm to 45 cm.”
vi. Volcanic ash (‘good article’).
“Volcanic ash consists of fragments of pulverized rock, minerals and volcanic glass, created during volcanic eruptions, less than 2 mm (0.079 in) in diameter. The term volcanic ash is also often loosely used to refer to all explosive eruption products (correctly referred to as tephra), including particles larger than 2mm. Volcanic ash is formed during explosive volcanic eruptions when dissolved gases in magma expand and escape violently into the atmosphere. The force of the escaping gas shatters the magma and propels it into the atmosphere where it solidifies into fragments of volcanic rock and glass. Ash is also produced when magma comes into contact with water during phreatomagmatic eruptions, causing the water to explosively flash to steam leading to shattering of magma. Once in the air, ash is transported by wind up to thousands of kilometers away. […]
Physical and chemical characteristics of volcanic ash are primarily controlled by the style of volcanic eruption. Volcanoes display a range of eruption styles which are controlled by magma chemistry, crystal content, temperature and dissolved gases of the erupting magma and can be classified using the Volcanic Explosivity Index (VEI). Effusive eruptions (VEI 1) of basaltic composition produce <105 m3 of ejecta, whereas extremely explosive eruptions (VEI 5+) of rhyolitic and dacitic composition can inject large quantities (>109 m3) of ejecta into the atmosphere. Another parameter controlling the amount of ash produced is the duration of the eruption: the longer the eruption is sustained, the more ash will be produced. […]
The types of minerals present in volcanic ash are dependent on the chemistry of the magma from which it was erupted. Considering that the most abundant elements found in magma are silica (SiO2) and oxygen, the various types of magma (and therefore ash) produced during volcanic eruptions are most commonly explained in terms of their silica content. Low energy eruptions of basalt produce a characteristically dark coloured ash containing ~45 – 55% silica that is generally rich in iron (Fe) and magnesium (Mg). The most explosive rhyolite eruptions produce a felsic ash that is high in silica (>69%) while other types of ash with an intermediate composition (e.g. andesite or dacite) have a silica content between 55-69%.
The principal gases released during volcanic activity are water, carbon dioxide, sulfur dioxide, hydrogen, hydrogen sulfide, carbon monoxide and hydrogen chloride. These sulfur and halogen gases and metals are removed from the atmosphere by processes of chemical reaction, dry and wet deposition, and by adsorption onto the surface of volcanic ash. […]
Ash particles are incorporated into eruption columns as they are ejected from the vent at high velocity. The initial momentum from the eruption propels the column upwards. As air is drawn into the column, the bulk density decreases and it starts to rise buoyantly into the atmosphere. At a point where the bulk density of the column is the same as the surrounding atmosphere, the column will cease rising and start moving laterally. Lateral dispersion is controlled by prevailing winds and the ash may be deposited hundreds to thousands of kilometres from the volcano, depending on eruption column height, particle size of the ash and climatic conditions (especially wind direction and strength and humidity).
Ash fallout occurs immediately after the eruption and is controlled by particle density. Initially, coarse particles fall out close to source. This is followed by fallout of accretionary lapilli, which is the result of particle agglomeration within the column. Ash fallout is less concentrated during the final stages as the column moves downwind. This results in an ash fall deposit which generally decreases in thickness and grain size exponentially with increasing distance from the volcano. Fine ash particles may remain in the atmosphere for days to weeks and be dispersed by high-altitude winds.”
If you’re interested in this kind of stuff (the first parts of the article), Press’ and Siever’s textbook Earth, which I read last summer (here’s one relevant post), is pretty good. There’s a lot of stuff in the article about how this stuff impacts humans and human infrastructure though I decided against including any of that stuff here – if you’re curious, go have a look.
vii. Kingdom of Mysore (featured).
“The Kingdom of Mysore was a kingdom of southern India, traditionally believed to have been founded in 1399 in the vicinity of the modern city of Mysore. The kingdom, which was ruled by the Wodeyar family, initially served as a vassal state of the Vijayanagara Empire. With the decline of the Vijayanagara Empire (c.1565), the kingdom became independent. The 17th century saw a steady expansion of its territory and, under Narasaraja Wodeyar I and Chikka Devaraja Wodeyar, the kingdom annexed large expanses of what is now southern Karnataka and parts of Tamil Nadu to become a powerful state in the southern Deccan.
The kingdom reached the height of its military power and dominion in the latter half of the 18th century under the de facto ruler Haider Ali and his son Tipu Sultan. During this time, it came into conflict with the Marathas, the British and the Nizam of Hyderabad, which culminated in the four Anglo-Mysore wars. Success in the first two Anglo-Mysore wars was followed by defeat in the third and fourth. Following Tipu’s death in the fourth war of 1799, large parts of his kingdom were annexed by the British, which signalled the end of a period of Mysorean hegemony over southern Deccan. The British restored the Wodeyars to their throne by way of a subsidiary alliance and the diminished Mysore was transformed into a princely state. The Wodeyars continued to rule the state until Indian independence in 1947, when Mysore acceded to the Union of India. […]
The vast majority of the people lived in villages and agriculture was their main occupation. The economy of the kingdom was based on agriculture. Grains, pulses, vegetables and flowers were cultivated. Commercial crops included sugarcane and cotton. The agrarian population consisted of landlords (gavunda, zamindar, heggadde) who tilled the land by employing a number of landless labourers, usually paying them in grain. Minor cultivators were also willing to hire themselves out as labourers if the need arose. It was due to the availability of these landless labourers that kings and landlords were able to execute major projects such as palaces, temples, mosques, anicuts (dams) and tanks. Because land was abundant and the population relatively sparse, no rent was charged on land ownership. Instead, landowners paid tax for cultivation, which amounted to up to one-half of all harvested produce.
Tipu Sultan is credited to have founded state trading depots in various locations of his kingdom. In addition, he founded depots in foreign locations such as Karachi, Jeddah and Muscat, where Mysore products were sold. During Tipu’s rule French technology was used for the first time in carpentry and smithy, Chinese technology was used for sugar production, and technology from Bengal helped improve the sericulture industry. State factories were established in Kanakapura and Taramandelpeth for producing cannons and gunpowder respectively. The state held the monopoly in the production of essentials such as sugar, salt, iron, pepper, cardamom, betel nut, tobacco and sandalwood, as well as the extraction of incense oil from sandalwood and the mining of silver, gold and precious stones. Sandalwood was exported to China and the Persian Gulf countries and sericulture was developed in twenty-one centres within the kingdom.
This system changed under the British, when tax payments were made in cash, and were used for the maintenance of the army, police and other civil and public establishments. A portion of the tax was transferred to England as the “Indian tribute”. Unhappy with the loss of their traditional revenue system and the problems they faced, peasants rose in rebellion in many parts of south India. […]
Prior to the 18th century, the society of the kingdom followed age-old and deeply established norms of social interaction between people. Accounts by contemporaneous travellers indicate the widespread practice of the Hindu caste system and of animal sacrifices during the nine day celebrations (called Mahanavami). Later, fundamental changes occurred due to the struggle between native and foreign powers. Though wars between the Hindu kingdoms and the Sultanates continued, the battles between native rulers (including Muslims) and the newly arrived British took centre stage. The spread of English education, the introduction of the printing press and the criticism of the prevailing social system by Christian missionaries helped make the society more open and flexible. The rise of modern nationalism throughout India also had its impact on Mysore.
With the advent of British power, English education gained prominence in addition to traditional education in local languages. These changes were orchestrated by Lord Elphinstone, the governor of the Madras Presidency. […]
Social reforms aimed at removing practices such as sati and social discrimination based upon untouchability, as well as demands for the emancipation of the lower classes, swept across India and influenced Mysore territory. In 1894, the kingdom passed laws to abolish the marriage of girls below the age of eight. Remarriage of widowed women and marriage of destitute women was encouraged, and in 1923, some women were granted the permission to exercise their franchise in elections. There were, however, uprisings against British authority in the Mysore territory, notably the Kodagu uprising in 1835 (after the British dethroned the local ruler Chikkaviraraja) and the Kanara uprising of 1837.”
Not from wikipedia, but a link to this recent post by Razib Khan seems relevant to include here.
I read it yesterday – a very enjoyable read, I’ve given it five stars on goodreads (the average rating is 4.28). This book is mostly about the Watch characters and it’s one of the ‘classic Ankh-Morpork stories’. I was actually wondering while reading it if I’d made the wrong choice recently when I gave Small Gods as a gift to someone unfamiliar with Pratchett – this one is much closer to ‘the average Discworld novel’ than Small Gods is, and even if I probably wouldn’t have given this particular book, a book like this one might have been a better choice (as for why I wouldn’t have given this one it’s not because it’s bad, it’s rather because it would be much more natural to start out with, say, Guards! Guards!)
Some quotes from the book, which is awesome (as the five star rating also indicates):
i. “Dwarfs are very attached to gold. Any highwayman demanding ‘Your money or your life’ had better bring a folding chair and packed lunch and a book to read while the debate goes on.”
ii. “There was a splintering noise across the street. They turned as a figure sprinted out of a tavern and hared away up the street, closely followed – at least for a few steps – by a fat man in an apron.
‘Stop! Stop! Unlicensed thief!'”
iii. “Dwarfs make a living by smashing up rocks with valuable minerals in them and the silicon-based lifeform known as trolls are, basically, rocks with valuable minerals in them. In the wild they also spend most of the daylight hours dormant, and that’s not a situation a rock containing valuable minerals needs to be in when there are dwarfs around. And dwarfs hate trolls because, after you’ve just found an interesting seam of valuable minerals, you don’t like rocks that suddenly stand up and tear your arm off because you’ve just stuck a pick-axe in their ear.
It was a state of permanent inter-species vendetta and, like all good vendettas, didn’t really need a reason any more. It was enough that it had always existed.* Dwarfs hated trolls because trolls hated dwarfs, and vice versa. […] ‘Don’t see why we can’t let ’em fight it out amongst themselves and then arrest the losers,’ said Corporal Nobbs. ‘That’s what we always used to do.'”
iv. “He was said to have the body of a twenty-five year old, although no-one knew where he kept it.”
v. “The rest of the Watch came trotting along Filigree Street as Vimes reached the Guild entrance. A couple of black-clad Assassins barred his way, in a polite manner which nevertheless indicated that impoliteness was a future option.”
vi. “Vimes would be the first to admit that he wasn’t a good copper, but he’d probably be spared the chore because lots of other people would happily admit it for him.”
vii. “Assasins did have a certain code, after all. It was dishonorable to kill someone if you weren’t being paid.” (to illustrate just how packed the book is with these kinds of remarks and quips, quote # iv is from page 54 and quote # vii is from page 63 – the quotes v and vi are from the pages in between…)
viii. “Dwarfs are known for their sense of humour, in a way. People point them out and say: ‘Those little devils haven’t got a sense of humour.’
ix. “Murder was in fact a fairly uncommon event in Ankh-Morpork, but there were a lot of suicides. Walking in the night-time alleyways of The Shades was suicide. Asking for a short in a dwarf bar was suicide. Saying ‘Got rocks in your head?’ to a troll was suicide. You could commit suicide very easily, if you weren’t careful.” […]
x. “Shouldn’t we be finding out who did it?’ said Angua.
‘Why?’ said Nobby.
She opened and shut her mouth once or twice, and finally came out with: ‘In case they do it again?’
‘It wasn’t an assasination, was it?’ said Cuddy.
‘No,’ said Carrot. ‘They always leave a note. By law.’
They looked at the drinks. They drank the drinks.
‘What a city,’ said Angua.
‘It all works, that’s the funny thing,’ said Carrot.
‘D’you know, when I first joined the Watch I was so simple I arrested the head of the Thieves’ Guild for thieving?’
‘Sounds good to me,’ said Angua.
‘Got into a bit of trouble for that,’ said Carrot.
‘You see,’ said Colon, ‘thieves are organized here. I mean, it’s official. They’re allowed a certain amount of thieving. Not that they do much these days, mind you. If you pay them a little premium each year they give you a card and leave you alone. Saves time and effort all round.’
‘And all thieves are members?’ said Angua.
‘Oh, yes, said Carrot. ‘Can’t go thieving in Ankh-Morpork without a Guild permit. Not unless you’ve got a special talent.’
‘Why? What happens? What talent?‘ she said.
‘Well, like being able to survive being hung upside down from one of the gates with your ears nailed to your knees,’ said Carrot.”
xi. “The river Ankh is probably the only river in the universe on which the investigators can chalk the outline of the corpse.”
xii. “‘He was a bit … unhinged, if you know what I mean. Head too full of brains. Ha, I remember he had this idea once of getting lightning out of lemons! Hey, Sendivoge, you remember Leonard and his lightning lemons?’
Sendivoge made little circular motions alongside his head with one finger. ‘Oh, yes. “If you stick copper and zinc rods in the lemon, hey presto, you get tame lightning.” Man was an idiot!'” (This exchange made me laugh out loud. If you’re completely lost, go here.)
xiv. “how come you know so much about all this stuff?’
‘Really, Nobby?’ said Carrot.
‘Had a special job, sir. Very responsible.’
‘And what was that?’
‘Quartermaster, sir,’ said Nobby, saluting smartly.
‘You were a quartermaster?’ said Carrot. ‘In whose army?’
‘Duke of Pseudopolis, sir.’
‘But Pseudopolis always lost its wars!’
‘Ah … well …’
‘Who did you sell the weapons to?’
‘That’s slander, that is! They just used to spend a lot of time away for polishing and sharpening.'”
xv. “‘He’s got a motive,’ said Nobby.
‘Yes. Hammerhock was a dwarf.’
‘That’s not a motive.’
‘It is for a troll. Anyway, if he didn’t do that, he probably did something. There’s plenty of evidence against him.’
‘Like what?’ said Angua.
‘He’s a troll.’
‘That’s not evidence.’
‘It is to Captain Quirke,’ said the sergeant.
‘He’s bound to have done something,’ Nobby repeated.
In this he was echoing the Patrician’s view of crime and punishment. If there was crime, there should be punishment. If the specific criminal should be involved in the punishment process then this was a happy accident, but if not then any criminal would do, and since everyone was undoubtedly guilty of something, the net result was that, in general terms, justice was done.”
xvi. “‘Did you know she was a werewolf?’
‘Um … Captain Vimes kind of hinted, sir …’
‘How did he hint?’
Colon took a step back.
‘He sort of said, “Fred, she’s a damn werewolf. I don’t like it any more than you do, but Vetinari says we’ve got to take one of them as well, and a werewolf’s better than a vampire or a zombie, and that’s all there is to it.” That’s what he hinted.'”
Khan Academy has, in collaboration with Stanford School of Medicine, made 15 videos about the disease (so far) with a total duration of two hours and 37 minutes – you can watch all of them here. There’s some overlap here and there, different videos covering similar stuff, and a lot of details are left out. But this is still good stuff and the videos were an enjoyable part of my day yesterday. I know I’ve covered this disease before, but given how many people have been exposed and how important it was in the past (roughly one hundred years ago one sixth of all French deaths were due to this disease), this is arguably a disease you should at least have some knowledge about. Some samples from the playlist below:
A quote from the last video above: “DOT – Directly Observed Therapy – is very important.”
There are theoretical reasons why DOT may be useful/efficient, as mentioned in the video. And I’ve seen it argued elsewhere that “treating tuberculosis with the DOTS strategy is highly cost-effective” [DOTS means “directly observed therapy, short course” – which is a specific type of DOT therapy; “a comprehensive tuberculosis management programme that focuses on low-income countries.” (see the Cochrane link for more)]. But I’m also aware that there are reasons to be skeptical as well:
The results of randomized controlled trials conducted in low-, middle-, and high-income countries provide no assurance that DOT compared with self administration of treatment has any quantitatively important effect on cure or treatment completion in people receiving treatment for tuberculosis.
PLAIN LANGUAGE SUMMARY
Directly observing people taking their tuberculosis drugs did not improve the cure rate compared with people without direct monitoring of treatment
Tuberculosis is a very serious health problem with two million people dying each year, mostly in low-income countries. Effective drugs for tuberculosis have been available since the 1940s, but the problem still abounds. People with tuberculosis need to take the drugs for at least six months, but many do not complete their course of treatment. For this reason, services for people with tuberculosis often use different approaches to encourage people to complete their course of treatment. This review found no evidence that direct observation by health workers, family members, or community members of people taking their medication showed better cure rates that [sic] people having self administered treatment. The intervention is expensive to implement, and there appears to be no sound reason to advocate its routine use until we better understand the situations in which it may be beneficial.”
Last week I visited my brothers and my parents, and I also interacted with a few others along the way. Overall the ‘short vacation’ was an interesting experience. I left my place Tuesday afternoon and I was back home in Aarhus Monday afternoon.
I stayed at my little brother’s place the first few days. He’s a student like me, lives in Copenhagen with his girlfriend. He was at work during the days I stayed there and came home in the late afternoon – not optimal, but that was the way it was going to be and I was happy to be allowed to stay with him for a few days. When I arrived the first evening he was relaxing playing a new consol game he’d gotten – I asked him and I think the name of the game was Skyrim, but I’m not completely sure (anyway that’s not important). He hasn’t played a game like that for a while, he mentioned to me that he’d had problems controlling the amount of time these things take out of his life, and so he’s been trying to avoid them – so maybe the day was badly chosen and unrepresentative, but anyway that was what he was doing that particular evening. The second evening the two of us visited my big brother – my little brother’s girlfriend was having fun with her sisters elsewhere – and we talked, had dinner, observed the little guy. Thursday evening I came ‘home’ late on account of having visited a friend in Copenhagen for most of the afternoon and part of the evening – back at my brother’s place it was an evening with TV, there was a programme about some policemen and the kind of stuff they do when they’re at work. Part of the programme focused on an area where a lot of people were partying, they spent some time covering that stuff. I decided to give it a bit of my attention for a little while, at least in part on account of it being so very different from what I usually do in the evenings (and you’re supposed to do different things from what you normally do when you’re on vacation, or so I’ve been told. I wasn’t completely successful, but I did try.). I left for my parents’ place Friday morning and stayed with them the rest of the time – they had friends from Wales visiting and I was curious to know how they were, what they were like, etc. I have seen them before a few times, but it’s a long time ago.
During the evening we visited my big brother one subject that came up was George Martin’s books – if I remember correctly, my big brother started the first one around Christmas and he was roughly half way through by now. My little brother had also started out on one of those books around Christmas, but the one he’d started was the second book, on account of him having already read the first one – and like my big brother, he was also roughly half way through the book at this point (he’d seen the series though, so he knew what was coming…). I read the first four books roughly within a month, and I completed the second half of the fourth book while I was visiting my little brother – I read more than they do. Visits like these make it easier for me to get an impression of what kind of stuff they might be doing instead.
Thursday evening I had my computer on while the TV programme was on, but I did follow some of the stuff that happened on the (-TV) screen. Along the way I asked some questions about the programme to my brother because I assumed, correctly, that he knew more about the context than I did; he did, in more ways than one. He’d watched the programme before, but aside from that there was also the fact that part of the program was set somewhere both he and his girlfriend had been while they were younger; a Danish area in Aalborg with a lot of bars where young people go to get drunk and have fun. The worlds of my brothers’ are different from my world in some key aspects, and the world at display in the programme was in a way a good illustration of how we’ve had different experiences when we were younger. I could never have enjoyed spending time there, where the programme was set – people seemed to be having fun in a setting where I’d be running for my life (loud music and noise everywhere; people everywhere – no, drunk people everywhere; some of the people you could see were in all likelihood under the influence of stuff besides alcohol). The behaviours of some of the people in the programme were really hard for me to understand – some of the people involved were repeatedly getting into physical fights with each other about ridiculous stuff (…one guy says something, the other guy responds, and one minute later they’re at each other’s throats – some of them seemed to have no self-control at all); one guy told the people who were interviewing him that he’d been convicted of a violent crime ‘three or four times’ (or was it ‘two or three’?) – he seemed to not even be sure how many times he’d committed violent crime and been punished for it by the authorities. He explained that he didn’t back down when people threatened him like some people do – he wasn’t a chicken, he was very focused on getting that point across to the people who interviewed him (…while I was thinking: ‘How old are you again? 5?). I tried to imagine what that guy might be doing for a living, and at the same time I also tried to imagine younger versions of my brothers in those bars some years ago, drinking and having fun like some of the people in the background whom the police did not see any need to talk to. It was quite hard – were they once ‘like that?’ Given that my little brother still goes to parties sometimes with his friends and get drunk with them, I assume ‘this kind of stuff’ (from my perspective) is not a part of his life he’s completely given up yet; this is an interesting thought.
The Welsh guy visiting my parents seemed to enjoy spending an hour or two of his afternoon watching people biking in France. He made it clear that he generally likes watching sports on television, and he made it clear that he was a little bit annoyed by the fact that he would be unable to watch a specific rugby match due to the timing of their vacation (he said it was no big deal, but you don’t bring up that kind of stuff in a discussion in the first place if you don’t care at all, so…). Given the kind of work he does (sales), he normally drives around 300 km per day on average. They were nice people, but they were very different from me.
What is a normal day like for most people? It’s different.
i. “Light burdens, long borne, grow heavy.” (George Herbert)
ii. “That there should one Man die ignorant who had capacity for Knowledge, this I call a tragedy.” (Carlyle)
iii. “Reason is poor propaganda when opposed by the yammering, unceasing lies of shrewd and evil and self-serving men.” (Heinlein)
iv. “Age is not an accomplishment, and youth is not a sin.” (-ll-)
v. “Progress doesn’t come from early risers — progress is made by lazy men looking for easier ways to do things.” (-ll-)
vi. “A generation which ignores history has no past — and no future.” (-ll-)
vii. “Expertise in one field does not carry over into other fields. But experts often think so. The narrower their field of knowledge the more likely they are to think so.” (-ll-)
viii. “Human beings hardly ever learn from the experience of others. They learn; when they do, which isn’t often, on their own, the hard way.” (-ll-)
ix. “The truth of a proposition has nothing to do with its credibility. And vice versa.” (-ll-)
x. “Always acknowledge a fault frankly. This will throw those in authority off their guard and give you opportunity to commit more.” (Mark Twain)
xi. “It is the business of science to offer rational explanations for all the events in the real world, and any scientist who calls on God to explain something is falling down on his job. […] If the explanation is not forthcoming at once, the scientist must suspend judgment: but if he is worth his salt he will always maintain that a rational explanation will eventually be found. This is the one piece of dogmatism that a scientist can allow himself—and without it science would be in danger of giving way to superstition every time that a problem defied solution for a few years.” (William Bonnor)
xii. “In general those who nothing have to say
Contrive to spend the longest time in doing it.” (James Russell Lowell)
xiii. “Tyrants seldom want pretexts.” (Edmund Burke)
xiv. “Custom reconciles us to every thing.” (-ll-)
xv. “All government — indeed, every human benefit and enjoyment, every virtue and every prudent act — is founded on compromise and barter.” (-ll-)
xvi. “Few rich men own their property. The property owns them.” (Robert Ingersoll)
xvii. “In nature, there are neither rewards nor punishments — there are consequences.” (-ll-)
xviii. “For the most part we inherit our opinions. We are the heirs of habits and mental customs. Our beliefs, like the fashion of our garments, depend on where we were born. We are molded and fashioned by our surroundings. ” (-ll-)
xix. “Most men are followers, and implicitly rely upon the judgment of others. They mistake solemnity for wisdom, and regard a grave countenance as the title page and Preface to a most learned volume. So they are easily imposed upon by forms, strange garments, and solemn ceremonies. And when the teaching of parents, the customs of neighbors, and the general tongue approve and justify a belief or creed, no matter how absurd, it is hard even for the strongest to hold the citadel of his soul.” (-ll-)
xx. “I would not wish to live in a world where I could not express my honest opinions. Men who deny to others the right of speech are not fit to live with honest men.” (-ll-)
I’ve read approximately half the book by now (320 pages). As I pointed out in the last post, “It’s pop sci and I have been disappointed a few times by some of the remarks he’s made during the first 200 pages”. A few examples of ‘irritating/disappointing remarks’:
“In practice all intermediates between pure hunter-gatherers and pure agriculturalists or pastoralists are found. But, earlier than about 10,000 years ago, all human populations were hunter-gatherers.”
Naturally the last sentence is what I take issue with, not the first part. It’s not that it’s wrong as such, but it will likely give people who don’t know any better the wrong impression – you can’t really leave it at that, without qualifying the statement a bit. As I’ve pointed out before, the development of farming and husbandry took thousands of years and what we still think of mostly as ‘hunter-gatherers’ did a lot of the work that brought about the changes necessary for human groups to switch to something close to the model of farming we know today. Dawkins speaks out against the widespread tendency to adopt an essentialist mindset in the field of taxonomy later on (‘the tyranny of the discontinuous mind’), but by mentioning a cut-off point like this without any qualifiers he’s in my view close to engaging in exactly the same kind of behaviour as are the people he’s criticizing. 10,000 years ago is an arbitrary cut-off point, and the ‘hunter-gatherers’ living before then were some places well on their way to developing farming as we know it – the distinction between ‘farmers’ and ‘hunter-gatherers’ was a lot more fluid in the far past than it is now. How far into the past the process went and how gradual the process from hunter-gathering to farming was surprised me a great deal when I read THP, but unfortunately I don’t have the book at my place at this point (I’ve borrowed it to a friend) – so wikipedia will have to do for now:
“Archaeologists have conducted an exhaustive study of Hut 1 at Ohalo II; this hut yielded over 90,000 seeds. The seeds account for more than 100 species of wild barley and fruits. Such a high concentration of seeds in the hut makes it highly unlikely that they were accidentally deposited into the hut via natural forces such as wind. In addition, statistical analysis demonstrates that the concentration of plant matter was significantly higher around the walls than the center. Had the seeds been deposited by the collapsed roof, they would have evenly scattered on the ground. Furthermore, just 13 species of fruit and cereal make up about half of the total number of seeds found in the area; these include brome grains (Bromus pseudobrachystachys), wild barley (Hordeum spontaneum) and millet grass grains (Piptatherum holciforme), just to name a few. This suggests a marked preference of certain species of edible plants. A seed of particular interest comes from the Rubus fruit, which was fragile, difficult to transport, and preferably eaten immediately after collection. The presence of Rubus seeds at the Ohalo II site could indicate that the seeds were dried in the sun or by the fire for storage: early evidence for advanced planning of plant food consumption. Most importantly, the extremely high concentration of seeds clustering around the grinding stone in the northern wall of Hut 1 led Ehud Weiss, an archeologist, to believe that humans at Ohalo II processed the grain before consumption. The exact spatial distribution of the seed around a grinding stone further indicates extensive preparation.”
This settlement burned to the ground around 19,400 BP. They may not have been ‘farmers’, but people who don’t know about people like these may get the wrong idea when reading Dawkins’ statement quoted above. Later on he mentions that, “Husbandry was not the overnight brainwave of some genius” and talks about the gradual changes required to get from where we were to where we ended up, both when it comes to husbandry and agriculture; but the unqualified 10.000 year mark is still bugging me a bit, and it’d not be hard to read the book and assume that the gradual changes mentioned later on took place only after 10.000 BP.
Here’s another annoying little quote: “It [Madagascar] is a natural botanical and zoological garden, which houses about five per cent of all the plant and animal land species in the world, more than 80 per cent of them being found nowhere else.” […] [two pages later:] “If you wiped out Madagascar, you would destroy about a thousandth of the world’s total land area, but fully four per cent of all species of animals and plants.” So which is it – four or five per cent? An editor ought to have caught that one and asked him to clarify or change one of the sentences. The repetition also really isn’t necessary. I’d expect stuff like that in a blog post, not in a published book. [see info’s comment…] Yet another:
[footnote:] “Carrots are rich in beta-carotene from which vitamin A can be made: hence the rumour – rumours can be true – that carrots improve vision.”
Yeah, well, if you’re going to include a sentence like that you’re gonna have to write a little more than that. Many people today are presumably aware of how the rumour in question came about but it’s likely that far fewer readers are aware of just how severe of a problem vitamin A deficiency still is in many developing countries (“Most common cause of blindness in developing countries […] Approximately 250,000 to 500,000 malnourished children in the developing world go blind each year from a deficiency of vitamin A, approximately half of whom die within a year of becoming blind.”).
I should point out that he talks about different speciation methods/mechanisms throughout the pages, but he doesn’t mention what they are called (see this for an overview) and his coverage is non-systematic and spread out over many pages. This is understandable given that it’s a pop sci book, but stuff like this is part of the reason why I rarely read such books.
Okay, enough with the critical remarks (I could easily include a few more but it’s not worth it) – there’s lots of really good stuff in there as well. I’ll just post a few quotes below with some ‘big picture’ stuff, but do note that most of the book is concerned with the details of how all this stuff happened – it’s a big narrative, going back hundreds of millions of years, a narrative about where we came from; and given that you need to spend some time talking about what the species which came before us were actually like. Did they have the same number of limbs as we do? How big were they? What did they eat? How did they get from A to B? Who else were around back then? And so on… Anyway, big picture stuff and some other interesting stuff from the book which I couldn’t help including below:
“Biological evolution has no priviliged line of descent and no designated end. Evolution has reached many millions of interim ends (the number of surviving species at the time of observation), and there is no reason other than vanity – human vanity, as it happens, since we are doing the talking – to designate any one as more privileged or climactic than any other. […] A living creature is always in the business of surviving in its own environment. It is never unfinished – or, in another sense, it is always unfinished. So, presumably, are we.”
“for particular genes, you are more closely related to some chimpanzees than to some humans. And I am closer related to some chimpanzees than to you (or to ‘your’ chimpanzees). Humans as a species, as well as humans as individuals, are temporary vessels containing a mix of genes from different sources. Individuals are temporary meeting points on the crisscrossing routes that genes take through history. […]
We normally assume that we can draw a single evolutionary tree for a set of species. But […] different parts of DNA (and thus different parts of an organism) can have different trees. I think this poses an inherent problem with the very idea of species trees. Species are composites of DNA from many different sources. […] each gene, in fact each DNA letter, takes its own path through history. Each piece of DNA, and each aspect of an organism, can have a different evolutionary tree. […] Species trees can be drawn, but they must be considered a simplified summary of a multitude of gene trees.”
“Rodents are one of the great success stories of mammaldom. More than 40 per cent of all mammal species are rodents, and there are said to be more individual rodents in the world than all other mammals combined.”
“Selection drives evolution only to the extent that the alternative types owe their differences to genes: if the differences are not inherited, differential survival has no impact on future generations.”
“Carnivora is an irritating name because, after all, it simply means meat-eater, and meat-eating has been invented literally hundreds of times independently in the animal kingdom. Not all carnivores are Carnivora […] and not all Carnivora are carnivores (think of the gentle giant panda, eating almost nothing but bamboo).”
“Geological time is large not only in comparison to the familiar timescales of human life and human history. It is large on the timescale of evolution itself. This would surprise those, from Darwin’s critics on, who have complained of insufficient time for natural selection to wreak the changes the theory requires of it. We now realise that the problem is, if anything, opposite. There has been too much time! If we measure evolutionary rates over a short time, and then extrapolate, say, to a million years, the potential amount of evolutionary change turns out to be hugely greater than the actual amount. […] Darwinian selection, if we impose it artificially as hard as we’re able, can drive evolutionary change at a rate far faster than we ever see in nature. […]
One million years, which is too short to notice in most parts of the fossil record, is 20,000 times as long as it takes to triple the oil content of maize seeds. […] these experiments serve to warn against looking at apparent trends spread over millions of fossil years, and naively interpreting them as responses to steadily sustained selection pressures.
Darwinian selection pressures are out there, for sure. And they are immensely important […] But selection pressures are not sustained and uniform over the sort of timescales that can normally be resolved by fossils, especially in older parts of the fossil record. The lesson of the maize and the fruit flies is that Darwinian selection could meander hither and yon, back and forth, ten thousand times, all within the shortest time we can measure in the record of the rocks. My bet is that this happens.
Yet there are major trends over long timescales, and we have to be aware of them too. To repeat an analogy I have used before, think of a cork, bobbing about off the Atlantic coast of America. The Gulf Stream imposes an overall eastward drift in the average position of the cork, which will eventually be washed up on some European shore. But if you measure its direction of movement during any one minute, buffeted by waves and eddies and whirlpools, it will seem to move west as often as east. You won’t notice any eastward bias unless you sample its position over much longer periods. Yet the eastward bias is real, it is there, and it too deserves an explanation.”
“Why bother to lose the wings? They took a long time to evolve, why not hang on to them in case one day they might come in useful again? Alas (for the dodo) that is not the way evolution thinks. Evolution doesn’t think at all, and certainly not ahead. […] Evolution, or its driving engine natural selection, has no foresight. In every generation within every species, the individuals best equipped to survive and reproduce contribute more than their fair share of genes to the next generation. The consequence, blind as it is, is the nearest approach to foresight that nature permits. Wings might be useful a million years hence when sailors arrive with clubs. But wings will not help a bird contribute offspring and genes to the next generation […in the specific setting in which the ancestors of the dodos found themselves, US. It seems obvious that in the general case wings do help birds get more offspring or they wouldn’t bother with them…], in the immediate here and now. On the contrary wings, and especially the massive breast muscles needed to power them, are an expensive luxury. Shrink them, and the ressources saved can now be spent on something more immediately useful such as eggs: immediately useful for surviving and reproducing the very genes that programmed the shrinkage.
That’s the kind of thing natural selection does all the time. It is always tinkering: here shrinking a bit, there expanding a bit, constantly adjusting, putting on and taking off, optimising immediate reproductive success. Survival in future centuries doesn’t enter into the calculation, for the good reason that it isn’t really a calculation at all. It all happens automatically, as some genes survive in the gene pool and others don’t. […]
Moas are extreme among flightless birds in that they have no trace of wings at all, not even buried vestiges of wing bones. They thrived in both the North and South Islands of New Zealand until the recent invasion by the Maori people, about 1250 AD. They were easy prey […] and the Maoris slaughtered them all, eating the choicer parts and discarding the rest, belying, not for the first time, the wishful myth of the noble savage living in respectful harmony with its environment. […] Perhaps as many as 200 species [of flightless rail] have gone extinct on tropical Pacific islands since human contact.” […other estimates are even higher]
I didn’t like it as much as I liked The Real Inspector Hound, but I did like it – I have mostly been thinking about whether to give it three stars or four on goodreads. In the end I went for the four star rating (the current goodreads average is 4.07); it’s a funny book and it made me laugh a few times. I assume there are still hidden gems in there to be found if I were to look closer, and that makes me hesitant to give it a relatively ‘low’ rating (even though 3 stars isn’t really low at all). An example of what I’m talking about is this quote, from a conversation between the ‘Player’ and Rosencrantz (or is it Guildenstern?):
“Ros – I mean, what exactly do you do?
Player – We keep to our usual stuff, more or less, only inside out. We do on stage the things that are supposed to happen off.”
Now, this is hardly an exchange you’d feel compelled to take much notice of. However the wonderful thing is that, as pointed out elsewhere: “Rosencrantz and Guildenstern Are Dead is structured as the inverse of Hamlet; the title characters are the leads, not supporting players, and Hamlet himself has only a small part. The duo appears on stage here when they are off-stage in Shakespeare’s play” (link).
A few other quotes:
“Do you ever think of yourself as actually dead, lying in a box with a lid on it?
Guil – No.
Ros – Nor do I, really … It’s silly to be depressed by it. I mean one thinks of it like being alive in a box, one keeps forgetting to take into account the fact that one is dead … which should make a difference … shouldn’t it? I mean, you’d never know you were in a box, would you? It would be just like being asleep in a box. Not that I’d like to sleep in a box, mind you, not without any air – you’d wake up dead, for a start and then where would you be? Apart from inside a box. That’s the bit I don’t like, frankly. That’s why I don’t think of it …
Guil stirs restlessly, pulling his cloak round him.
Because you’d be helpless, wouldn’t you? Stuffed in a box like that, I mean you’d be in there for ever. Even taking into account the fact that you’re dead, really … ask yourself, if I asked you straight off – I’m going to stuff you in this box now, would you rather be alive or dead? Naturally you’d prefer to be alive. Life in a box is better than no life at all. I expect. You’d have a chance at least. You could lie there thinking – well, at least I’m not dead!”
“Guil – I think I have it. A man talking sense to himself is no madder than a man talking nonsense not to himself.
Ros – Or just as mad.
Guil – Or just as mad.
Ros – And he does both.
Guil – So there you are.
Ros – Stark raving sane.”
“Guil – Go where?
Ros – To England.
Guil – England! That’s a dead end. I never believed in it anyway.
Ros – All we’ve got to do is make our report and that’ll be that. Surely.
Guil – I don’t believe it – A shore, a harbour, say – and we get off and we stop someone and say – Where’s the King? – And he says, oh, you follow that road there and take the first left and – (furiously) I don’t believe any of it!
Ros – It doesn’t sound very plausible.”
I’ve started reading The Ancestor’s Tale by Richard Dawkins. It’s pop sci and I have been disappointed a few times by some of the remarks he’s made during the first 200 pages (the pages in the book covering the stuff about which I assume I know the most), but taking it for what it is so far it’s still an enjoyable (and easy) read.