We're also likely to be switching to a new server in mid to late September. I'll keep you posted when it's going to happen.

(In case you're wondering why the warnings are necessary, this blog appears to be turning into a community hub these days; if it goes down for any length of time I get email, and lots of it ...)

The rules:

You can ask me a question in the comments. Just one. I will answer if it pleases me to do so (and I will not answer questions that annoy or bore me or duplicate information in the FAQ or earlier answers). If I don't/can't answer but am not annoyed/bored I may issue you a coupon good for a second or subsequent question.

If there's a backlog of ten or more unanswered questions, don't bother posting until you see me answering the earlier ones. (Otherwise I may ignore you.)

Also note: I am in eastern Australia right now, nine hours ahead of the UK and 15 hours ahead of the US west coast. Nor am I an insomniac. If you get an instant answer, hey: someone got lucky!

So. Who's first?

This Wednesday, at 5pm, I'll be signing books (and maybe reading) at Infinitas Bookshop in Parramatta (Shop 22 Civic Arcade 48-50 George Street).

This Thursday, at 5:30pm I'll be doing a joint signing (with fellow Orbit authors Kate Elliott and Karen Miller) at at Galaxy Books in Sydney (143 York Street). I'm also planning on hitting the Redoak beer cafe afterwards to unwind: company welcome.

AussieCon are working on finalizing their program schedule. Here are the events I know I'm on, so far. (Note that Monday's schedule is liable to change, or they'll be carrying me away in a box — right now I'm down for four consecutive hours in front of an audience, which is a little intense.)

Fri 1300 Rm 203: (Panel) The future of privacy

Sat 1500 Rm 219: (Panel) Cyberpunk and the city

Sun 1100 Rm 219: (Panel) Anachronistic fiction: successors to steampunk

Sun 1300 Rm 201: Kaffeeklatsche

Mon 1100 Rm 219: Reading

Mon 1200 Rm P3: (Panel) The grandfather paradox

Mon 1300 Rm 201: Signing

Mon 1400 Rm P3: (Panel) Hand-waving, rule-breaking, and other dirty tricks of hard sf

(To folks who normally have access to my mobile phone number: I have a new one while I'm in Australia. Drop me an email if you need to get in touch. The old number will be back on September 10th.)

Even allowing for self-serving reporting (the FBI would obviously find it useful to inflate the threat of crime, if only to justify their budget requests), that's a lot of money being pumped down a rat-hole. Extrapolate it worldwide and the figures are horrendous — probably nearer to $300Bn a year. To put it in perspective, it's like the combined revenue (not profits; gross turnover) of Intel, Microsoft, Apple, and IBM — and probably a few left-overs like HP and Dell — being lost due to deliberate criminal activity.

Where does this parasitic drag come from? Where did we go wrong?

I'm compiling a little list, of architectural sins of the founders (between 1945 and 1990, more or less) that have bequeathed us the current mess. They're fundamental design errors in our computing architectures; their emergent side-effects have permitted the current wave of computer crime to happen ...

In the Von Neumann architecture, data and executable code are stored in the same contiguous memory in a computer; in Harvard Architecture machines, data and code have separate, disjoint areas of memory and never the twain shall meet. Von Neumann architectures are simpler and cheaper, hence were more popular for about the first forty or fifty years of the computing revolution. They're also more flexible. Allowing data and executable code to share the same address space allows for self-modifying code and for execution of data as code — sometimes these are useful, but they're horrible security holes insofar as it permits code injection attacks to happen. There have been some recent moves by the likes of Intel in their more recent architecture iterations to permit chunks of memory to be locked to one function or the other, thus reducing the risk of code injection attacks — but it's too little, and much too late.

2) String handling in C uses null-terminated strings rather than pointer-delimited strings. A null character (ASCII 0) denotes the end of a string (a block of adjacent memory cells containing one character of data each) in the C programming language's memory management (cough, choke) system. What if you want to write a string containing ASCII 0, or read or write beyond a null? C will let you. (C will not only let you shoot yourself in the foot, it will hand you a new magazine when you run out of bullets.) Overwriting the end of a string or array with some code and then tricking an application into moving its execution pointer to that code is one of the classic ways of tricking a Von Neumann architecture into doing something naughty.

In contrast, we've known for many decades that if you want safe string handling, you use an array — and stick a pointer to the end of the array in the first word or so of the array. By enforcing bounds checking, we can make it much harder to scribble over restricted chunks of memory.

Why does C use null-terminated strings? Because ASCII NUL is a single byte, and a pointer needs to be at least two bytes (16 bits) to be any use. (Unless you want short strings, limited to 256 bytes.) Each string in C was thus a byte shorter than a pointer-delimited string, saving, ooh, hundreds or thousands of bytes of memory on those early 1970s UNIX machines.

(To those who might carp that C isn't really used much any more, I should reply that (a) yes it is, and (b) what do you think C++ is compiled to, before it's fed back to a compiler to produce object code?)

3) TCP/IP lacks encryption at the IP packet level. Thank the NSA in the early 1980s for this particular clanger: our networking is fundamentally insecure, and slapping encryption on high-level protocols (e.g. SSL) doesn't address the underlying problem: if you are serious about comsec, you do not allow listeners to promiscuously log all your traffic and work at cracking it at their leisure. On the other hand, if you're the NSA, you don't want the handful of scientists and engineers using the NSF's backbone to hide things from you. And that's all TCP/IP was seen as, back in the early 80s.

If we had proper authentication and/or encryption of packets, distributed denial-of-service attacks would be a lot harder, if not impossible.

DNS lacked authentication until stunningly recently. (This is a sub-category of (3) above, but shouldn't be underestimated.)

4) The World Wide Web. Which was designed by and for academics working in a research environment who needed to share data, not by and for banks who wanted to enable their customers to pay off their credit card bills at 3 in the morning from an airport departure lounge. (This is a whole 'nother rant, but let's just say that embedding JavaScript within HTML is another instance of the same code/data exploit-inviting security failure as the Von Neumann/Hardward Architecture model. And if you don't use a web browser with scripting disabled for all untrusted sites, you are some random black hat hacker's bitch.)

5) User education, or the lack of it. (Clutches head.) I have seen a computer that is probably safe for most users; it's called an iPad, and it's the digital equivalent of a fascist police state: if you try to do anything dodgy, you'll find that it's either impossible or very difficult. On the other hand? It's rather difficult to do anything dodgy. There aren't, as yet, any viable malware species in the wild that target the curated one-app-store-to-rule-them-all world of Apple. (Jailbroken iOS devices are vulnerable, but that's the jailbreaker's responsibility. Do not point gun at foot unless you have personally ensured that it isn't loaded and you're wearing a bulletproof boot.)

In the meantime, the state of user interfaces is such that even folks with degrees in computer science often find them perplexing, infuriating, and misleading. It's hardly surprising that the digital illiterati have problems — but a few years of reading RISKS Digest should drive even the most Panglossian optimist into a bleak cynicism about the ability of human beings to chew gum and operate Turing Machines at the same time.

6) Microsoft.

Sorry, let me rephrase that: Bloody Microsoft.

Specifically, Microsoft started out on stand-alone microcomputers with a single user. They took a very long time to grasp multitasking, and much longer to grasp internetworking, and even longer to get serious about security. In fact, they got serious about memory protection criminally late — in the early to mid 2000s, a decade after the cat was out of the bag. Meanwhile, in their eagerness to embrace and extend existing protocols for networking, they weren't paying attention to the security implications (because security wasn't an obvious focus for their commercial activities until relatively recently).

We have a multiculture of software — even Microsoft's OSs aren't a monoculture any more — but there are many tens or hundreds of millions of machines running pre-Vista releases of Windows. Despite Vista being a performance dog, it was at least their first release to take security seriously. But the old, bad, pre-security Microsoft OSs are still out there, and still prone to catching any passing worm or virus or spyware. And Microsoft, by dropping security support for older OSs, aren't helping the problem.

Anyway, I'm now open for suggestions as to other structural problems that have brought us to the current sorry state of networking security. Not specific problems — I don't want to hear about individual viruses or worms or companies — but architectural flaws that have contributed to the current mess.

Where did we go wrong?

While I'm there I will be doing a couple of readings and book signings.

First up is Infinitas Bookshop (Shop 22 Civic Arcade 48 - 50 George Street, Parramatta), where I'll be reading and signing from 5:30pm to 7pm on Wednesday 25th.

And if you can't make that one, there's a joint signing (with Kate Elliott and Karen Miller) at Galaxy Bookshop (143 York Street, Sydney) from 5:30pm on Thursday 26th.

Then I'll be showing up at Aussiecon 4, the world science fiction convention, in Melbourne (from September 2nd to 6th). I don't have my program schedule yet, but when I do I'll list it here.

Let's see. It's a decade-and-a-bit since Web 1.0 exploded messily. 2007 saw the initial bursting of the real estate bubble, propagating worldwide in 2008 and expanding into a full-bore liquidity crisis and a near-collapse of the global banking system. 2010 sees the Euro zone in crisis, somewhat mitigated by a spurt of growth in the German economy — and a British government that seems hell-bent on triggering a painfully sharp double-dip recession by slamming the brakes on government spending excessively hard.

On an orthogonal note, I am getting the impression from my reading that the accounting regulations imposed by Sarbanes-Oxley in the US has drastically reduced the attractiveness of the traditional IPO as an exit strategy for founders of start-ups: this might even be retarding the growth of a second web/mobile related market bubble.

Stuff is churning away under the waterline of the global economy. We're living through a period of unprecedented rapid change. Taking measures to suppress bubbles seems to be the new orthodoxy — after all, no investor likes to lose their shirt — but I've got a gut feeling that if you suppress bubbles you just end up building up pressure for an explosion somewhere else.

What am I missing?

For those who were asleep when the Clue Fairy rang the doorbell, the narrative goes like this:

Some fusion processes produce highly energetic neutrons which render reactor components radioactive with activation products through the continuous bombardment of the reactor's components with emitted neutrons. Because of this bombardment and irradiation, power generation must occur indirectly through thermal means, as in a fission reactor. However, the appeal of helium-3 fusion stems from the aneutronic nature of its reaction products. Helium-3 itself is non-radioactive. The lone high-energy by-product, the proton, can be contained using electric and magnetic fields. The momentum energy of this proton (created in the fusion process) will interact with the containing electromagnetic field, resulting in direct net electricity generation.

He 3 looks at first sight as if it could be the key to clean nuclear power — that is, to fusion reactors that live up to the original promise of not producing shedloads of high level waste. However, He 3 is vanishingly rare on Earth.

At this point, enter, stage left, a Space Cadet: He 3 is rare, therefore it's expensive. But there's He 3 in the lunar regolith, trapped there after being blasted out by the solar wind. We should go to the moon and mine He 3! It'll solve all our energy problems!

Unfortunately there are a couple of problems.

Firstly, nobody's built a commercially successful fusion reactor yet. ITER plan to build a working test-bed; it's logical successor would be a working prototype first generation power reactor. There are huge obstacles to overcome, not least in developing neutron capture techniques and breeding D/T fuel. These are engineering problems (sorry, annoying paywall) and theoretically amenable to solution — but at a price of billions of euros and decades of work, and even then, it may turn out to be too costly to be a viable competitor for well-understood fourth generation fission technology and a mature waste disposal/fuel recycling chain. And that's before we look to a speculative second generation reactor, running on a different type of fuel, that — because of the higher Coulomb barrier between He nuclei — requires a far higher temperature (on the order of 500M to 1Bn degrees celsius, rather than the relatively chilly 100M degrees C required for D/T fusion).

Given the average generation time for a new reactor technology of 20-30 years, and development costs on the order of $50Bn-100Bn per generation, we won't be even thinking about prototyping an He3 reactor until 2060 at the earliest.

Secondly, there's very little He 3 in the lunar regolith. The amount is non-zero, but we can also breed the stuff on Earth: Neutron bombardment of Lithium, Boron, or Nitrogen targets, or decay of Tritium are currently used. Breeding He 3 requires a high neutron flux, but unless the plan is to automagically shift us all over to a "clean" He 3 power cycle instantly, He 3 reactors will be coexisting with "dirty" high-flux fission or fusion reactors for many decades.

Is it really going to be cheaper to send monster trucks to the moon, than to build a couple of special-purpose high neutron flux reactors optimized for mass production of Tritium (and thereby for production of He3 as a decay product)?

The whole Lunar He 3 mining proposition is a boondoggle, based on wishful thinking: that (a) we can make a working commercial fusion reactor (not yet proven, and will cost some tens of billions of dollars to get to that point), (b) if we run a more advanced — and much hotter — reactor on He 3 it produces somewhat fewer secondary neutrons, (c) He 3 is vanishingly rare on Earth but there is a tiny amount of He 3 in the Lunar regolith, so (d) MOON!!!11!!ELEVENTY!! WITH MONSTER TRUCKS AND BULLDOZERS!!!

He 3 is not magic high-energy pixie dust. And in the context of the space colonization debate it should be seen for what it is — a placeholder for the alchemist's stone that will turn the money-hole of a lunar colony into a profit centre: an extractable natural resource that can't be found on earth and is valuable enough to mine elsewhere. Unfortunately, the harder you look at the value proposition, the more it comes to resemble a pig in a poke.

To mark the occasion, Tor.com are running a web seminar on Heinlein for a week, starting today; various people (myself included) will be discussing his work in the context of his first 41 years. I'm still digesting the book (I'm currently up to 1942) but will contribute in due course — and will point you at my Tor.com posting as and when it's up.

In the meantime, for those of you who might expect a more personal perspective from me ...

To say Robert Heinlein was a pivotal figure in the history of written science fiction is a bit like saying that water is wet: well duh. But what's coming through from the biography is that his emergence as that pivotal figure was anything but inevitable. He was driven and immensely (if not uniquely) talented, and he set his hand to enough enterprises that success in one of them was inevitable. Writing fiction for pulp magazines was both a long shot and some way down his list of desired outcomes — if anything, it was a consolation prize for missing the vocations he'd really desired (first, a naval career: second, the chance to make a difference for his fellow men and women through a career in progressive politics). And, at least through his first forty years, his political beliefs were very different to those attributed to him in later life — his early fiction is to some extent a misleading guide to his actual thinking, as his work was tightly tailored to John W. Campbell's publishing agenda (in order to pay the mortgage and supplement his navy pension).

Much to think on here. But I'll be saying it elsewhere. In the meantime, though, just one thought: I only discovered Heinlein in my mid-teens, so I have a rather different literary relationship with him from most (American) SF authors.

For those of you who care but who've lost track of such things, "Rule 34" is the kinda-sorta sequel to "Halting State". It's set five years later, is not about MMOs or virtual reality, and none of Jack, Elaine, or Sue appear in it (although Sue's boss, DI Kavanaugh, is one of the major characters). It's a crime novel — or, more accurately, a criminology novel, insofar as it looks at the future of crime and policing in the post-internet age.

According to my notes I started writing on March 2nd, 2009 and didn't get it nailed down until August 6th, 2010. Which is to say, don't expect me to squirt books like this out every year.

And when you were fifteen, you took Jesus for an alibi &mdash lest the other girls at school realize what you were.

As for you? You're not gay, you insist: it's just that you like to fuck other men.

You all have secrets. But the net knows them all. And if it doesn't, it holds the gaps in the graph of all your interpersonal transactions — and can therefore discern the shape of the shadows that fit the implied spaces. Nothing escapes the net.

Net? Internet?

No. This is not that net. This is the other net. The one that features in your nightmares. The net that knows your secret sins. The net of blind justice; the net that holds the sea of shame. The net that binds you softly, the better to lift the onerous burden of free will.

Knowing all, forgiving nothing. This is your story, as the net sees it.

Your story.

Crime story.

I'm pleased to announce the existence of a new! signed! limited edition! of my short story collection, "Toast and other Stories". Originally planned as the valuable, collector's final edition (that was to come out just before "Wireless"), it's been delayed by nearly two years — but it's at the printer now, with orders due to ship on August 28th. Remember, there are only 700 copies — once they're gone, they're gone!

Attempts to discuss the prospects of human exploration and inhabitation of the cosmos on the internet tend to attract a certain type of participant. If you've been following the comment threads here you probably recognize them ...

There is an ideology that they are attached to; it's the ideology of westward frontier expansion, the Myth of the West, the westward expansion of the United States between 1804 (the start of the Lewis and Clark expedition) and 1880 (the closing of the American western frontier). Leaving aside the matter of the dispossession and murder of the indigenous peoples, I tend to feel some sympathy for the grandchildren of this legend: it's a potent metaphor for freedom from social constraint combined with the opportunity to strike it rich by the sweat of one's brow, and they've grown up in the shadow of this legend in a progressively more regulated and complex society.

My problem, however, is that there is no equivalence between outer space and the American west.

Humans are a climax organism that is fundamentally dependent on a couple of key ecosystems. There's the one we carry around in our guts — about a kilogram of bacteria and fungi, for a typical adult — without which we can't even digest most of our food. And there's the ecosystem we live in. (Or ecosystems. Because of our unique horizontally-transferable tool culture we can adapt to existence in terrestrial ecosystems other than the one our ancestors coevolved with. But there are limits; we don't thrive in Antarctica, or at the bottom of the ocean trenches.) We're also somewhat dependent on our extraordinary extended phenotype, from flint hand-axes to Space Shuttles. Maintaining that phenotype is a large-scale operation supported by a penumbra of extended cultural activities that maintain the ability to maintain the phenotype — primary school teachers, for example, don't bend metal but are absolutely vital to the activity of engineering insofar as you've got to start educating your next generation of engineers somewhere. Hence some earlier postings on this blog.

Basically, it's not clear how large a system you need to support human civilization. We don't know how to build biospheres from scratch yet, and indeed there's worryingly little research being done on the topic (which may become a screamingly important priority in another half century, if the most pessimistic climate change projections are accurate). We can make a rough back-of-the-envelope guess at the size of human population it takes — given abundant raw materials and a favourable biosphere — to maintain a technological civilization; it's many orders of magnitude larger than the proponents of Heinlein's nostrum that "specialization is for insects" may be comfortable with.

There may be possible technological solutions to both problems that don't require the combined lifelong effort of millions of humans. We don't have (a) strong artificial intelligence, (b) self-replicating machines that can work from raw materials extracted from their natural environment, (c) "magic wand" space propulsion technologies (which may themselves be Fermi paradox solutions insofar as their existence implies either flaws in our current understanding of physics or drastically efficient and thereby destructive energy sources), or (d) the ability to re-engineer ourselves. If any one (or more) of these are achievable, then all bets against space colonization are off.

But. But. But.

The west was inhabitable; it supported a healthy set of interlocking ecosystems in most of which a lone human being could find food and sustenance. (There were exceptions.) It already supported a human population. The colonists were equipped with adequate technology and were crossing distances that were, at a pinch, amenable to shanks' mare and a walking stick.

These conditions do not apply in space. You don't get to breathe the air on Mars. You don't get to harvest wheat on Venus. You don't get to walk home from an asteroid colony with 5km/sec of velocity relative to low Earth orbit. You don't get to visit any of these places, even on a "plant the flag and pick up some rocks" visitor's day pass basis, without a massive organized effort to provide an environment that can keep the canned monkeys from Earth warm and breathing.

I postulate that the organization required for such exploration is utterly anathema to the ideology of the space cadets, because the political roots of the space colonization movement in the United States rise from taproots of nostalgia for the open frontier that give rise to a false consciousness of the problem of space colonization. In particular, the fetishization of autonomy, self-reliance, and progress through mechanical engineering — echoing the desire to escape the suffocating social conditions back east by simply running away — utterly undermine the program itself and are incompatible with life in a space colony (which is likely to be at a minimum somewhat more constrained than life in one of the more bureaucratically obsessive-compulsive European social democracies, and at worst will tend towards the state of North Korea in Space).

In other words: space colonization is implicitly incompatible with both libertarian ideology and the myth of the American frontier.

It occurs to me that besides the obvious ramifications we've been chewing over (read the comment thread if you dare — it should only take a couple of hours), if you turn this question on its head it looks like a component of a set of answers to the Fermi Paradox.

In general, there are two classes of solution to the Fermi paradox; ones that assume that we are unique special snowflakes in an empty cosmos, and those that postulate that intelligent species are common, but some kind of mechanism stops them from colonizing interstellar space.

If we look at the second problem set, and broaden the focus ... well, intelligent species emerge as components of a biosphere bound to a particular planetary habitat. We humans are land-dwellers on Earth in the later high-oxygen period; conditions on earth even one billion years ago would have been rapidly fatal for an unprotected human, and even today, survival on 90% of our planet's surface area is contingent on the availability of cultural artefacts like boats (80% is water) or clothing (for protection in hostile climates). So the real question isn't, "can intelligent life colonize other star systems?" so much as "can intelligent life propagate itself, and its supporting biosphere and technosphere to run in alien environments? Which is a very different question. Call it the Ark Problem; if your name is Noah and you're going on a one-way trip to another world, how big an Ark do you need (and how many specimens per speciality, be they biological or technological)?

(Last time I asked the minimal-biosphere question here, while ploughing a space colony furrow, one of the first answers was "oh, you just need humans and blue-green algae". That, plus soy beans and tilapia and five dollars won't buy you a latte in Starbucks — especially once your colonists begin dying of obscure micronutrient deficiency diseases.)

But enough with the ark problem and defining the minimum population of a stable self-maintaining technosphere; there are other fun concepts that might bear on the Fermi Paradox. Chief among these is the Simulation argument. (In fact, I gather Steve Baxter has written a paper about it, but it doesn't seem to be on the web.)

Loosely stated, the simulation argument runs thuswise (pace wikipedia): it is taken as axiomatic that consciousness is an emergent property of physics (i.e. there's no ghost in the machine), and that we can simulate physical systems. Thus, it is possible in principle to construct a software simulation of a world inhabited by intelligent beings who will perceive that world as real. It then follows that either no civilization will ever reach a technological level capable of constructing such simulations, or that every civilization capable of doing so will choose not to do so for some reason, or ... we're probably living in a simulation (because any civilization capable of running a civ-sim is liable to do so many, many times; so the number of sim-civilizations will vastly outnumber the number of authentic ones, and by the principle of mediocrity we are not exceptional).

(NB: you can find a more formal treatment of the simulation argument in Nick Bostrom's original paper, although the idea goes back some way before then, to Hans Moravec and earlier less rigorous speculators.)

It's that danged principle of mediocrity that's causing all these problems. It shows up in the Fermi Paradox, it turns up in the Simulation Argument, it turns up like a bent penny in all sorts of places — it's a big problem for the standard model of spacetime, once you start digging into the Boltzman Brains paradox (for a quick intro, look here or here). Indeed, it seems to me to be a corollary of the weak anthropic principle.

... And I've run out of brain cells with which to continue this line of thought, but a dangling question remains: how relevant is the simulation argument to the Fermi paradox, either (naively) as a solution, or as a mode of temporal reasoning for examining the possibility of our being alone in the cosmos?

What is the minimum number of people you need in order to maintain (not necessarily to extend) our current level of technological civilization?

There are huge political ramifications hiding behind this question. Let me unpack them for you.

I think these ideas are mostly delusional because they rely on a fundamental misapprehension about the world around us — namely that we live in a society that can be made simple enough to comprehend.

Let's take a look at the superficial structures around us. How many people does it take to design a new automobile? Back in Henry Ford's day, it needed an office full of draughtsmen, a handle of senior engineers to sort out each major mechanical subsystem (gear train, engine, electrics, brakes, suspension, bodywork), and experts on coachbuilding to dictate the shape of the bodywork. There would be time and motion men to dictate the speed and sequence of assembly line activities, and more drafting work to design the tools the production line workers would use ... it took the effort of a few hundred men.

But modern cars are different. A typical 2010 automobile may contain roughly 20-30 electric motors and actuators (for everything from the central locking system to the air conditioning and the motorized seats and windows). There's a similar number of microprocessors involved in everything from the engine and gearbox management systems to the entertainment, navigation, communication, and accident mitigation systems (for example, the sensors and microprocessors that control the sequence of pyrotechnic detonators that inflate air bags, tension seat belts, and collapse the steering column in event of a collision). The in-car electronics alone require on the order of 10-20 million lines of code to run all these services — which implies the combined efforts of thousands of software developers, never mind the small army who design not only the body panels but the handling tools the production line robots use to install them. Cars are no longer user-serviceable because they're nearly as complex as 1960s airliners.

And as for your smartphone? The damned thing has a component count somewhere between ten major subsystems and frame components and a hundred billion (if you go down to the smallest scale and count the capacitors in its FLASH memory). The number of fab lines on the planet that can make memory chips of that density is limited, and they rely on rare elements mined only in exotic locations and in tiny abundance.

Medicine: let's not go there. Back in the late 19th century, we had doctors, nurses, surgeons, pharmacists, and dentists. Today, each of those professions has exploded into platoons and battalions of sub-specialities, and their roles are supported in turn by complex industries full of strange niches.

Around 1900, it took the effort of about 20-30% of a nation's work-force to provide food for everybody; and another 30-50% working in factories to produce clothing, machinery, and processed materials like bricks and billets of pig iron. Today, we only need 0.5-1% of the work force to feed everyone, and another 1-4% working in industry to produce the basics — but the microspecialities have exploded, to the extent that a lot of our needs seem to require a trans-national economy to provide. There are only two vendors of wide-body airliners on any scale today, Boeing and Airbus, and both of them are effectively multinational consortia (more than half the components of the Boeing 787 Dreamliner are produced overseas, and shipped to Seattle for final assembly). There seems to only be room for one vendor of super-Jumbo airliners — if Boeing and Airbus tried to exploit that niche simultaneously, they'd both starve — so they appear to be avoiding conflict in that (and some other) area(s). And so on.

So. I ask: how many people does it take, as a minimum, to maintain our current level of technological civilization?

I'd put an upper bound of about one billion on the range, because that encompasses basically the entire population of NAFTA and the EU, with Japan, Taiwan, and the industrial enterprise zones of China thrown in for good measure. (While China is significant, more than half of its population is still agrarian, hence not providing inputs to this system).

I'd put a lower bound of 100 million on the range, too. The specialities required for a civil aviation sector alone may well run to half a million people; let's not underestimate the needs of raw material extraction and processing (from crude oil to yttrium and lanthanum), of a higher education/research sector to keep training the people we need in order to replenish small pools of working expertise, and so on. Hypothetically, we may only need 500 people in one particular niche, but that means training 20 of them a year to keep the pool going, plus future trainers, and an allowance for wastage and drop-outs by people who made a bad career choice. Higher education accounts for 1.8-3% of gross spending in the developed world, with primary and secondary education taking a whopping chunk on top of that (if you spent 10 years in a school with a staff:pupil ratio of 1:10, then you soaked up a person-year of time; there may be more labour going into pre-university education than goes into agriculture and industry combined).

As to those political implications ...

Firstly: no, you can't simplify a complex society that runs on just-in-time delivery and a host of specialities. You need a huge training back-end to provide for the thousands of skilled graduate-entry niche occupations. You need an efficient just-in-time delivery system to keep everyone supplied with food, water, power, shelter and whatever else they need — it's that, or accept huge inefficiencies in your supply chain that wipe out the gains produced elsewhere.

Secondly, seemingly similar artefacts (cars, phones, airliners) have invisibly accreted complexity. The complexity makes them better (safer, more economical, more luxurious) than their predecessors, but vastly more difficult to engineer; stuff that used to be fixable by shade-tree mechanics and jobbing electricians has receded over the horizon. Back in the early 19th century, the complement of a sailing ship could expect to maintain the ship in every significant way using tools and expertise that they could carry aboard the ship. Today in the early 21st century, that's not an option with airliners or probably even automobiles.

Thirdly, the complexity embodies in these new products means that their production is dependent on a complex web of lower-level specialities.

Fourthly, there are more side-effects to keep track of. Exotic materials mean exotic contamination events from waste dumping, for example.

Fifthly: space colonization? Get back to me when you've tracked down how many people it takes to design and build a space suit. (The number is in the hundreds, if not the thousands.) More realistically, we won't have autonomous off-world colonies unless and until they can cover all the numerous specialities of the complex civilization that spawned the non-autonomous, dependent-on-resupply space program. Or, to put it another way: colonizing Mars might well be practical, but only if we can start out by plonking a hundred million people down there.

You can keep your jet pack and food pills; one sign we're living in the right century is the TGV V150, a train so fast that at top speed the wheel rims are nearly going supersonic. Take a peek at this video (if you're impatient, the money shot is at 9 minutes and 35 seconds in) and remember: it's nuclear powered! (France gets 78.8% of its electricity from nuclear reactors — the highest proportion of any nation on Earth.)

2. Vacations!

Five to eight weeks of vacation time per year is normal for French employees, along with twelve statutory holidays. Until recently they were also working for 35 hours per week. Not so much use to self-employed workaholics like me, but if you work to live rather than living to work, you get an extra few years of leisure time over your career.

3. World's best healthcare

That's according to the World Health Organization. France has a universal healthcare system that costs 30% less per capita than the US system and delivers better outcomes than the US system provides for those who can afford it. Oh, and it's 77% state funded; what insurance companies there are, are non-profit mutual societies. While the UK's NHS is leaner and cheaper, the French system is better.

4. Did not invade Iraq

That whole "cheese-eating surrender monkey" thing is a canard: when George Bush and Tony Blair tried to convince Jacques Chirac to join them in taking down Saddam Hussein he told them where to stick it because, prior to his career as the Republic's #1 Crook, he was a captain in the French army during the Algerian War. Unlike Bush and Blair, he knew from personal experience exactly how easy a western occupation of an Arab state wasn't going to be. Nor was he impressed by the whole Gog-Magog thing. Which is why France didn't pour billions of euros and hundreds if not thousands of lives down a fruitless rat-hole.

5. Cheese!

(Am too busy salivating to eulogize.)

Commenters: your challenge is to come up with five good things to say about a country that you do not, and never have, lived in.

One noteworthy point that has emerged from this trip is that I am, indeed, capable of spending ten days away from home with an iPad instead of a laptop. The day before we left, my desktop machine ate its hard drive. (Do not worry: there is an up-to-date backup, and a replacement drive in my hand luggage waiting to be installed when I get home.) And my iTunes library is too big to live on my Macbook Air. So I figured I'd give the iPad an extended test, and it's come through fine.

As you can see, I can blog from it. (The keyboard dock helps, though.) I can do regular email chores, too. I haven't been using it for serious writing work, but I managed to get down the outline of a short story that I'll probably write when I get home. All in all, it's nicer than any netbook I've travelled with. While there are rumours circulating that Apple are going to release a new, smaller Macbook Air this autumn, I think the iPad is still likely to occupy the sweet spot for Apple portability. However, I think I will chicken out and take a laptop as well when I head for worldcon this August/September — I'll be gone for over three weeks, and I reckon two weeks is probably the pain threshold for not having a real computer on tap.

(Stuff I can't do with the iPad? Buy DVDs and rip them. Research-driven writing that requires me to have a multi-tabbed browser and a word processing app open simultaneously (although iOS 4 should go most of the way towards fixing that). Carry around my entire 70Gb iTunes library. Browse the really annoying websites that throw up so many ads that I need AdBlock Plus or NoScript to read them. Manage the Airport Express wifi router I keep in my travel kit. Plus some other stuff that, on average, I do less than once every two weeks — write code, play desktop games, that sort of thing.)

Final note: I've been doing so much R&R style tourism stuff that I haven't been soaking up enough crazy ideas to blog substantively about anything. So it may take a few days before normal service is resumed. Feel free to talk among yourselves in the meantime ...