Archive for January, 2011
One of the more remarkable gifts our technological world is the increase in our life expectancy. Even but a century ago the average life expectancy of a British man was half of that of today, even in the last two decades it’s gone up by five years. This increase has a myriad of reasons; an abundance of food, water, law and order, an increase in hygiene and sanitation and finally massive advances in medical science.
Extending one’s life and capability through innovative means is part of what makes us human. This trend of increasing life expectancy is one that doesn’t seem to be slowing down, indeed as we develop our biosciences we are gaining a deeper understanding as to the mechanisms of ageing. This occurred to me as a topic to talk about when I saw an article on the BBC news website reporting on the state of anti-ageing science. The report highlighted a few issues that were vehemently discussed in the comments, to get to the issues I’ll go over a bit of the science behind ageing.
We don’t fully understand every mechanism that goes on whilst we age. There are many contributing factors that we have discovered though; the most often touted cause of ageing is the shortening of telomeres. These are stretches of DNA found at the end of chromosomes, every time a cell replicates a bit of these telomeres are cut off. Over time this leads to shortened telomeres and a more likely chance of DNA damage. Other contributing factors include protein build up inside and outside of cells, DNA mutation and cellular replacement (many cell types die faster than they can be replaced, this is more apparent in the elderly). Designing therapies to counter all of these (and any undiscovered causes) would lead to a stabilisation and even reversal of the ageing process.
This is all interesting science but it has far reaching consequences for our society and people have a lot of different ideas about the ethics of life extension. Let’s imagine that effective treatments for all the causes of ageing are produced, in this scenario a regime of drugs is introduced to the public that when taken every day reverse your age to a physically fit, healthy 25 year old body and keep it that way. I’ve heard many arguments for why this is apparently a bad thing. A common argument is that we should not “play god” or “mess with the natural order”. The argument states that death is natural and any attempt to prevent death from old age is morally wrong. Whenever I am faced with this argument I simply ask the person if they take medicine, drive cars or use the internet. If the answer is yes then the argument for being unnatural seems pretty thin. Furthermore nobody has ever died from old age; people die from age related disease. Getting old is simply a slow wearing out until finally something vital fails. In curing old age diseases we ramp up the life expectancy. Are these people really going to advocate not researching medicines for these diseases? Are they going to tell elderly patients “we don’t have medicine for your kind. It’s natural! Accept it”?
Another popular argument is that of overpopulation. Proponents state that if we do not allow people to die the world will be overfull. I’m always sceptical of this claim; firstly it assumes that we cannot support this amount of people. In the year 1800 we could not have supported the 6 billion people we have today because it took over 200 years of technological development for us to be able to support us. The claim that there will be too many people assumes that this progression will not continue. Secondly the claim assumes that we will still give birth to as many people as we do today. Add to that the fascinating discovery made over the last century that if you give women rights, education and prospects they (shock horror) don’t want to spend their lives spitting out children like high-throughput human factories! The birth rate in countries with equal rights for women shrinks enormously. Couple this with the decreasing need to have so many children (you don’t need to have 12 in the hope 6 will survive to adulthood to take care of you) and we get a scenario of 1 or less children per adult.
For me life extension always makes me wonder; I am 21 years old; once I’ve lived that many years again I hope to have had kids, be married and have a good career. At that age I can expect that once I’ve lived that many years again I will probably be dead or close to it. But that is on the basis that near 80 is the age I will kick the bucket. If the regime of drugs we have supposed comes to pass and my life expectancy jumps from 80 to several hundred years I doubt my principles will stay the same. Why have kids at any age before 100? Why not spend a few centuries learning, travelling and establishing a good life before tying myself down with other humans to raise?
Personally I would work for decades then take a sabbatical (instead of retirement) and spend a few decades travelling, studying and generally being on holiday. I’m interested to know what you all think. Do you think age-stabilising drugs would be a good thing? What would you do if your life expectancy jumped by orders of magnitude? How do you think society would change? Ultimately these issues are nothing new, but as science marches on our life expectancy is shrinking over the horizon. So who knows? Perhaps one of you will be mulling over this blog on your 200th birthday…
I’ve stated it before on this blog but these days we are surrounded by people peddling “alternative medicines” and the like in an attempt to gain funding for what ultimately, has either not been proved to work or proved not to work. One of the biggest perpetrators of this is homeopathy also called homeopathic medicine. Homeopathy was concocted by Samuel Hahnmann a little over two hundred years ago. He disliked the philosophies of the then current medicine and instead attempted to develop a field of medicine based on the principle of “like-cures-like”. Hahnmann believed that if something was to cause a set of symptoms in one amount then in a much lower amount it would surely cure the same symptoms, specifically if that substance was massively diluted in water and repeatedly shook it would release its ‘healing energy’ into the mixture which is then called a remedy. He went on to test many different substances by getting people to take them and record every symptom they then suffered. This practice is called “homeopathic proving” and the records of the symptoms from each substance are then stored in books known as “repertoires”. Using all of this the practice of homeopathy goes a little like this…
Patient: I have aches in my feet, a swollen neck and am feeling nauseous.
Homeopath: let me consult my repertoire……Ah I see, a teaspoon of X causes those symptoms. Ill prepare a remedy of diluted X and you will be better before you know it.
There is a wealth of evidence showing that homeopathy does not work as a medicine. Aside from the notion of like-cures-like not having any basis in anything other than wishful thinking the dilutions that homeopaths use ought to demonstrate to anyone that this is at best, an outrageous scam and at worse, a dangerous idea. (As a side note like-cures-like does not apply to vaccination which relies on the exposure of antigens to the immune system. I’m not going to go into immunology right now because it is a huge field but if you are interested wikipedia, contrary to popular belief, is quite a good start). To accurately describe how diluted homeopathic ‘remedies’ are I’m going to have to go over a little bit of chemistry…
All matter is formed of atoms; these atoms can bind together in groups to form molecules. Due to the different masses of different elements (for example; a single oxygen atom masses more than a carbon atom) if we have a gram of one element and a gram of another they will not have the same amount of atoms in them. This is a bit like having a tonne of bowling balls and a tonne of tennis balls; bowling balls are bigger and weigh more so there will be less of them, tennis balls are smaller and weigh less so we need far more than bowling balls to make up a tonne.
If we want to have a sample with one atom of substance A for every one atom of substance B we have to do a bit of working out. There’s a useful unit in chemistry known as a mole (not to be confused with a mole), one mole is roughly 6 billion trillion molecules or atoms (depending if the fundamental unit of the substance is a molecule [e.g. water] or an atom [e.g. iron]). To know how many grams of a substance you need to make one mole you need to find out its atomic weight, simply looking at a periodic table will tell you this (I’m not going to get into how we weigh atoms!). The atomic weight of oxygen and carbon are 16 and 12 respectively, therefore 16 grams of oxygen has the same number of atoms as 12 grams of carbon.
So how does this little chemistry lesson apply to homeopathy? I’m going to go through step by step how to make a homeopathic remedy of salt. The first thing a homeopath does is make a 1 in 10 dilution (homeopaths call this a “1X”); salt is made from the molecule NaCl (a molecule of one sodium and one chloride atom). One mole of NaCl is 58 grams; one mole of water (H2O) is 18 grams. To make a 1 in 10 dilution where we have one NaCl molecule to one H2O molecule we can put 5.8 grams of salt into 18 grams of water. Shake the sample to make sure it’s evenly mixed and voila! Now we have a 1X solution.
The next step is to do the same thing again, diluting one part of this solution into ten parts water. Now for every NaCl molecule there are 100 molecules of H2O and it doesn’t stop there. Homeopaths repeat this shaking and 1 in 10 diluting dozens of times. Remember the number of molecules in a mole? It’s 6 billion trillion (or 6×1023), at the beginning when we had an equal amount of salt to water we had this many NaCl molecules, with every dilution we’ve got 10x less so after twenty-three dilutions there will likely now only be six NaCl molecules in the entire solution. Beyond this limit of only there are only two options; the first is that every time a sample of the solution is taken to dilute in more water some of these six molecules goes with it. This would mean that the 24th dilution was not dilute 10x more than the 23rd. Secondly (and far more likely) these six molecules wont be picked up and all that will be transferred is water, in that case the sample is no longer a dilution but a pure solution of water. From then on any more 1 in 10 mixing is not diluting but merely mixing water on its own. Unfortunately the story gets worse…
Most people could probably see that half a dozen molecules of something is not going to have a great effect on your body but twenty-three dilutions only creates what’s called a 12C remedy. Apparently this isn’t good enough and this solution is then diluted further, the problem with this is that if the solution only has one molecule of a substance in it then diluting it a further ten times in water means that to maintain just one molecule you need ten times more water. After twenty-three dilutions the sample will contain only water but homeopaths advocate remedies to be diluted sixty times! This is called a 60x solution. It’s difficult to understand just how dilute this would be if it still contained just one NaCl molecule;
The Earth is nearly 8000 miles wide. Imagine a globe the size of the Earth but made entirely of water, that’s 1 billion trillion litres of water. Now make that globe a member of a team containing 100 globes. Make that team a member of a group containing 100 teams. Make that group a member of a company containing 100 groups. Make that company a member of a cohort containing 100 companies. Finally make that cohort a member of a system containing 100 cohorts. In one system there are 10 billion globes. Add to that just one molecule of NaCl and that’s how dilute a 60x salt solution is.
At his point it should be obvious that homeopathic remedies are just water and aren’t worth the tap they came out of. But homeopaths in light of this evidence still stick to their guns. When homeopathy was being concocted by Hahnmann it was not known if matter was made of fundamental units or if it could be divided infinitely. Since the discovery of atoms we have known that this is untrue and this leads to preposterous scenarios needed in the dilutions as mentioned above. But homeopaths today try to get round this by arguing that water has memory. Yes they claim that pure water when mixed with a substance and shook repeatedly remembers what was in it and takes on the properties of this substance, purportedly by forming a network of water molecules around the substance to mimic it. But this last attempt at saving their ideology is by far the easiest to prove wrong. To start with if water has memory that doesn’t bode to well for our recycling of toilet water into drinking water (hence the expression “homeopathy is full of shit”), secondly this would mean that the water’s healing properties are due to it replicating the effect of the substance in it. If this were true it would violate the idea that a dilution is stronger because instead of having just the substance in water the entire water now acts as the substance! Lastly the time in which water molecules change places and orientation to form new networks is on the order of picoseconds (meaning it happens nearly a trillion times per second), far too short a time for any memory.
In spite of having no evidence for like-cures-like, remedies so far diluted they are just water and no evidence for claims of a memory system in water homeopathy is still a huge and active movement in the western world. The matter is only complicated by figures such as Prince Charles (a man with no scientific or medical credentials) stating that homeopathy should be considered. Homeopathy should be considered as much as any unproven or disproven field in medicine, it is not fair if homeopathy get’s to sidestep the stringent drug testing that any proper medicine must undergo purely on the basis of people’s choice or popular figures ideas. The issue is far worse though, a report by the House of Commons Science and Technology Committee revealed that the NHS is spending money on homeopathic treatments. Worryingly there is no exact data on how much is being spent and on what, however it is estimated that homeopathic remedies cost the NHS over £150,000 a year (outrageous when A, it’s water from a tap and B, in an earlier post I talked about how some people feel £100,000 a year for Paul Mason was not deserved) and the cost of running the four homeopathic NHS hospitals we have in the UK is quoted as being near £12 million.
The only shred of justification modern homeopathy has is that it can act as a placebo. A placebo is a substance administered to a patient that does nothing biochemically relevant to their condition but due to the patient believing they have taken medicine they show improvement. The placebo effect is controversial as it may only work by making the patient less aware of their discomfort whilst their body heals naturally, it cannot heal beyond what the body can heal unassisted anyway and there is an ethical dilemma in lying to a patient about their treatment. But if homeopathic remedies are an effective placebo then there is no reason why they could not just be replaced, very easily, very cheaply by a nice, refreshing bottle of evian.
I hope this post has enlightened you a little on what exactly homeopathy is and how it claims to work. I hope I have stimulated a curiosity to learn about these things and how we can know if something has evidence or not. In the modern world the veracity of any medicine (and indeed any science) is only confirmed through repeated, demonstrable experiments by different parties. The data from these experiments can then be published (providing the research was logically and methodologically sound) for other scientists to examine, repeat and have their results also published. Through this long meticulous process we can ascertain what works and what does not. Now more than ever we can ill afford to allow untested, unproven medicines and sciences to gain funding at the expense of that that has fairly passed the best tests known to man.
The cuckoo is infamous for two things; regularly jumping out of clocks and laying its eggs in other bird’s nests. These cuckoo chicks when born sometimes even try to push the other eggs out of the nest before stealing the attention and food of the mother. This situation isn’t a unique one in either nature or our society, there are limited resources in this world and in this time of economic recovery and budget cuts there’s even less to go around. Ensuring that the right people get the allocation they need is vital however our society is plagued with pseudo-science, everywhere we look we can see adverts and advocates claiming ‘scientific’ proof for whatever it is they’re selling. This is done to add some cloak of authority to whatever is being said and it’s a dangerous abuse of trust that leads people to distrust real science. So how do we sort the snake-oil salesmen from the pharmacist, the nutritionist from the dietitian? In short, how can we detect the cuckoos of science?
Without a background in the field it is difficult for anybody to tell if what they are hearing is correct. This is true for all of us; everybody is ignorant of far more than they know. But you don’t have to run off and get a PhD in a subject to determine the truth. There are some tell tale arguments that people use when pretending something is science.
- You can’t prove me wrong!
Frequently proponents of ideas such as intelligent design cite the fact that they have not been proved wrong as some sort of evidence for their ideas veracity. In arguments on the subject the supporters will often make statements along the lines of “well you can’t prove it’s not true so I’m going to keep believing it”. This is flawed logic. If we assumed that things were true until we proved them wrong we would have to believe in far more than we disbelieved. You can’t prove me wrong that there are invisible, intangible pixies whispering in my ear that if I don’t jump 100 times a day they will pull my pants down in public so I should do it right? Of course not! That’s not to say that we disbelieve everything until its proven correct either, if there is no evidence for or against something then it is an unknown. Something is unknown until there is evidence for it (or evidence to show it is not possible). Remember this, if somebody is claiming to know something that is unknown or unknowable then their claim has no evidence, as such it is not science.
- It’s been around for ages.
This argument I’ve always found particularly odd. People often claim that the older something is the more valid it must be. There is perhaps a grain of truth to this if a method is old then it must work to some respect for it to be used for all that time, but that doesn’t mean that a better and newer method doesn’t exist. Often with this people claim “science changes its mind all the time”. No, science adjusts its views based on what’s observed and progresses. If a text book is different to a text book from four years ago it’s a good thing, the latest will be more up to date and have more accurate information. Ideas such as herbal medicine and fundamentalist religion often tout how long their practices have been about as if that were evidence for their truth. Be particularly wary of this when it comes to medicine, when people claim that such-and-such medicine has been used to great effect for thousands of years ask them why it is that it is not used in real medicine. The answer may be something along the lines of “big pharma just want to make money and so make synthetic poisons”. If you ever hear any conspiracy crap like that just walk away, anything that works as a medicine is investigated thoroughly over years of intensive study. If it works it’s called “medicine”, if it doesn’t it’s called “not medicine”. There is no such thing as “alternative medicine”.
- It’s 100% natural.
Alternative medicines and fashionable diets are particular perpetrators of this statement. There is an idea that if something is natural it is better and if something is manmade or synthetic then it must be poison. This fails to take into account that most medicines are natural! Whether a chemical is synthesised by a plant as a byproduct of its biology or in a lab with beakers and test tubes as long as it is the same chemical it will do the same thing. The advantage of synthesising medicines in the lab is that you get just the medicine you need. A prime example is aspirin, derived from willow bark it is an effective analgesic. Eating the willow bark by itself is likely to cause you to throw up. If you’re still not entirely convinced just ask yourself this; if natural, unprocessed material straight from Mother Earth was all we needed then why do we have so much disease? Why weren’t hunter gather societies healthier than those of today?
There are many other signs to look for that I will probably go into more in later posts. Key things that I look for are the credentials of the proponent of an idea (remember not everyone who calls themselves a doctor ever got an MD or PhD) and their agenda (are they pushing religion? A product they are selling?). It is important for us all to remain vigilant towards those who would deceive us to either get our money or take funding from worthwhile causes. Beyond the economy is it really good for our health if we let medicine that is unproven or proven not to work into our health service? Or that we teach religious views on the origin of our species over what we have evidence for?
At the end of Christmas time I settled down to watch what I thought would be one of those typical Channel 4 documentaries called Britain’s Fattest Man. If you missed it the documentary was about Paul Mason who became the world’s heaviest man weighing in at over 440kg (that’s 70 stone or 980lb for all you imperialists)! Not to go through the whole documentary but in essence it was very sad, Paul became this size after suffering a series of devastating blows in his life before becoming addicted to food. He was bedridden and required carers to wash and feed him. Paul was desperate enough to go for a gastric bypass (a procedure that shrinks the available stomach size) which enabled him to shed 120kg in just a matter of months.
You may ask why I am bothering to blog about this, I had no plans to. It was merely one of those stories we hear about and perhaps relay in a shocked tone to others. The thing that really got me about this documentary was the way people treated Paul. Other than receiving hate mail I was dismayed to see a wealth of articles both online and in newspapers lamenting the cost of Paul’s care and medical treatment. Per year Paul costs slightly over £100,000 to the NHS and over the fifteen or so years Paul has needed this care he has topped over £1,000,000. Reading through some comments online I couldn’t believe the amount of people who were advocating Paul either not receiving this care or not deserving it. This is a bit of a problem for me, I believe in social healthcare. I think medicine should be a right not a privilege. There’s two dangerous mentalities here, one is that if you don’t contribute you don’t deserve (ridiculous, what about students, mentally ill, prisoners and those down on their luck) and the other is that if you did it to yourself you don’t deserve help. To me that’s a pretty slippery slope to start on.
It is possible to go through your whole life without smoking or exposing yourself to any airborne carcinogens and still get lung cancer. The following numbers aren’t real but they illustrate a real point; out of 100 non smokers 20 get lung cancer and out of 100 smokers 60 get lung cancer. Now out of those 60 smokers with cancer 1 in 3 could have contracted the disease independent of their smoking. If we adopt the mentality of “you don’t deserve healthcare if you did it to yourself” we have to deny or charge for care for 40 of them. But it’s impossible to tell! Do we just deny all of them because they took a risk? Even though every third man didn’t cause it themselves? This principle is very damaging and whilst I don’t condone Paul Mason eating himself to that size I certainly don’t think he is any less deserving than a healthy taxpaying member of society. The whole philosophy of social healthcare is that those who can contribute so that all can receive any and every medicine or treatment that they require.
What do you think? Is Paul justified in receiving medical treatment? At the end of the day would you rather live in a society which takes care of those in need or one that dismisses those who can’t help themselves?
First things first I need to declare that I am indeed one of those long haired, lab coat wearing boffins known as a scientist. I have always been a scientist even before I actually got to wear the coat. From a very young age I wanted to know things, I wanted to figure things out and I wanted to use that knowledge to build wicked stuff (I’ve still not entirely fulfilled my childhood dream of building my own spaceship but we’ll see…). I do accept however that I am in the minority. Most people don’t like studying science whether it’s because they find it hard or boring or perhaps just have a penchant for something else. But there is a problem with this that I have come to notice over my (admittedly short) career, whilst its absolutely fine if people don’t want to be scientists most people don’t even know what science is. And that as we shall see is like being a sailor whose doesn’t recognise the water beneath him…
It should be self evident to anyone reading this blog that we live in a technologically developed world. I’m touching a variety of pressure sensors that are converting that pattern into a digital code that is then represented on my screen as words and images. That code can be distributed on the interwebz for all to enjoy. Our lives are an expression of an ocean of knowledge that has been painstakingly gathered and built upon over thousands of years. There’s little I can point to in my life or the lives of anyone I know that hasn’t been affected by science and technology. This brings us neatly to our first question “what’s science and whose technology?”
The broad definition of science that most people might say is that it is a process of gathering facts about the world. A more accurate definition though would be that science uses empirical reasoning to build predictive models about the world; it’s all about model building. Empirical reasoning in science simply put goes observation – hypothesis – experimentation – conclude. We observe natural phenomenon, we develop a hypothesis about how it occurs (what in colloquial terms may be called a ‘theory’ or ‘idea’), we then test this hypothesis and from that we make a conclusion. Technology is the application of the understanding drawn from these models. We build shiny machines and funny sounding chemicals that run on the principles we have discovered to perform tasks that we find desirable.
What makes science so different? Sometimes in life truths are rather unpalatable for us humans. Whether it’s finding out that the Earth doesn’t revolve around us, that we are indeed related to other animals or that yes our bum does look big in this there is a plethora of things about the world that many might not like. But whether or not you like an answer has no veracity on its truth. Whilst this seems obvious it’s a statement I often see disregarded; just watch Fox News or read the Daily Mail and you’re bound to be bombarded with ideas like climate change is a conspiracy, vaccines cause disease and that its only ‘fair’ to teach fundamentalist religion in school science classes as a matter of ‘balance’.
In science no answer, no matter how devastating to our world view, is disregarded or accepted on the basis of what it is. The only reason to accept anything in science is that it has evidence for it no matter what it is. Science isn’t about what people think or what people reckon based on personal experience or anecdotes they’ve read about, it is about demonstrable truth through good, repeatable unbiased experimentation. This doesn’t mean that I go and do some experiments then just tell you the answer, other scientists will repeat my work over and over to see if the results are correct, to see if my method was flawed or to see if the results I obtained do not match the conclusions I have made. Nobody’s word is taken as gospel in the scientific community, something is considered to be true only when it has been demonstrated time and again by other experts in the field. This is the peer review process and I will go into it in more detail in another post.
So why is it important that everybody understands how science works? We all rely on the fruits of its labour to survive and flourish; in the developed world we live in a Garden of Eden where we suffer little threat from parasites, predators, natural disasters and where food and water are plentiful. All this is a product of science and technology but don’t take it as a constant! There are people in this world who have little interest in truth, merely agenda. It is because of these people that we all must have a fair understanding of how science works, if we don’t then how can we know what to do about issues such as climate change, pandemics and so on? A scientifically illiterate person has no immunity to the bullshit and propaganda that surround us like wolves beyond the campfire. How can the public know whether it’s right to teach evolution or creationism? To vaccinate or not? These are issues that I will address in further depth later on, until then I hope I’ve sparked a curiosity and shed a little more light on what exactly this ruddy ‘science’ thing actually is.
Not just men in fact but women as well. The question has been one that I’ve been throwing back and forth for a while now. I’ve encountered similar questions before all essentially asking “how many people does it take to sustain a technologically developed society?” The question implies a society that we in Britain are used to with as much consumerism, technology, law and light bulbs as we have today. The answer might be a little more than most would guess.
Throughout history we have gone forth and multiplied. Countless times wooden boats have been built carrying less people than the average train on the Tube across waters to new lands where those people have managed to build a society. From that we would think that the answer to “how many people does it take to sustain a technologically developed society?” wouldn’t be that much. Perhaps the citizens of our hypothetical society can each be employed only in jobs that are necessary with no overlap or needless jobs (by needless jobs I refer to multiple companies providing the same service which in our hypothetical society can be cut down). In colonial times they would start essentially from scratch and work their way back up with trade and supply from neighbouring lands boosting the fledgling society. But in trying to answer “how many men…” we need to come to a number of how many people we need to maintain the world we are used to rather than rebuild it.
Pre-1900 most things could be constructed by generalist industries (blacksmiths, carpenters, masons etc). Over the past century however our world has exploded into an ecology of superspecialisms. Whilst early machines could be built or maintained by the typical tinkerer in his workshop the complexity of everyday objects today has pushed the reality of one dedicated jack-of-all-trades up to a large interdependent group of masters in one field.
A few examples; today’s smartphones contain microprocessors built from transistors just tens of nanometres thick, wires etched a few dozen atoms wide, GPS systems, radio transmitters, microscopic pressure sensors underneath a full colour screen all packaged in a palm sized container. In the medical field rather than having the traditional doctor, surgeon, nurse, dentist we have specialists in far narrower fields like cardiologists, radiologists, neurologists, ophthalmologists etcetera etcetera. Examples like this can be seen in all walks of life and in building our hypothetical society we can forget none of them! A temporal lobe neurosurgeon might seem unnecessarily specialised until you get a tumour that needs to be excised. And for each field we must have a sizable portion educating the next generation. Contrary to Heinlein’s popular quote specialisation is not just for insects.
So to address the original question, how many men does it take to make a light bulb? Let’s break it down; a typical incandescent light bulb is made up from a glass bulb containing a tungsten filament surrounded by an inert gas. Sounds simple at first but for all of that we need an industry to mine and refine the materials, transport to take those materials to factories (and consequently an industry to maintain that infrastructure), make the bulbs and ship them out to the people. Apply that to every product we have and how many industries do we need now? Sure there may be no overlap in some areas (we may only need one tungsten mine and one infrastructure maintenance consortium) but the sheer complexity of life in the developed world today is mind boggling.
Adding together the populations of large hives of industry such as NAFTA, the EU and China we come to a number of over two billion. This number can be trimmed to about one billion by taking into consideration the communities that provide little overall input (half of China’s population is solely agrarian for example). If we take one billion people to be the upper bound we can consider removing as much overlap as possible whilst maximising efficiency but I see no reason as to why the lower bound number would not be less than the high tens or low hundreds of millions. So to live in a society capable of providing all the technologies and services we are used to would require a population greater than that of the United Kingdom today.
This realisation has important implications. For those of an ideology that the world would be a better place with less people simply living in one with nature or those who have a special place in their heart for the idea of living on Mars (or any other non-Earth body) the reality is quite different. To maintain a technologically developed society such as ours we are not going to be living in self sufficient pioneering communities, instead we have to be a thriving interdependent hive of industries, experts and above all specialists.