Discussion Board

Topic: Malthus, Bayes and Brandon Carter.

From: Richard Blaber.
Location: Wellingborough, Northamptonshire, England.
Date: 11/11/2008

I am, unfortunately, not a mathematician, so I am struggling here, and relying on intuition perhaps rather more than logic. However, I have come to the tentative conclusion that there must be a way of combining the arguments of the Rev Thomas Malthus and Dr Brandon Carter - the so-called 'Doomsday Argument', itself derived from Bayesian statistics.
The key variables are population (P), total food produced (F), total potable water supply (W), and total energy supply (E). The latter would have to be divided by c^2 to achieve dimensional consistency, with F and W measured in kgs/annum if the SI is used.
It is clear that, if the ratio F + W + E/P declines, whether because of increased population relative to resources, or declining production, or both, then people have a problem, because there is less per head, and when that happens, competition for resources gets fiercer and the gap between the resource-rich and the resource-poor gets wider. That is a sure recipe for conflict on a massive scale.

Re: Malthus, Bayes and Brandon Carter.

From: Greg Bear
Date: 11/11/2008

Mathematical predictions fail in the face of large-scale complexities. Malthus's direst predictions have yet to come true--but at least he inspired Darwin! Interestingly, evolutionary theory in Russia (and we're not talking about Lysenko and Stalin here--a disastrous anomaly) went down a somewhat different path--they were unaware of Malthus.

Re: Malthus, Bayes and Brandon Carter.

From: Richard Blaber.
Location: Wellingborough, Northamptonshire, England.
Date: 11/15/2008

With regard to the alleged 'failure' of Malthus's predictions - tell the 178 million malnourished children in the world, and the 1.5 million children who die each year from hunger (WHO statistics) that Malthus's predictions have failed, and I don't think they will believe you (of course, you would have to explain to them who Malthus was, and what he predicted, but that is a minor quibble). You may find what the WHO has to say about threats to food security illuminating - at least I hope so.
As to the issue of complexity - this is a smokescreen. I am well aware of chaos theory, and of Godel's undecidability proofs, but non-linear dynamics does not apply here. I am not trying to predict what the weather in Topeka, Kansas, is going to be like at 1700 UT on Thursday, June 21, 2040. Short of being in possession of Dr Who's Tardis, and paying a visit and reporting back, there is no way of doing such a thing (and the violation of enforced ignorance - non-linearity and undecidability - might constitute a proof that time machines of the Tardis type are impossible).
If, on the other hand, you know that proven reserves of oil, coal and natural gas will be exhausted by 2050 at the latest, even at present rates of consumption; that millions of people are threatened by food and water shortages, and that these are going to get worse if no remedial action is taken; that global warming will cause catastrophic average temperature increases, again unless urgent remedial action is taken; and that human population growth is outstripping the planet's capacity to cope with it, as the WWF has argued, then you need to act.
My prediction, such as it is, is not an absolute: I am not saying, 'The extinction of H. sapiens is inevitable' - although it is, at some point in the future. Indeed, the entire Universe faces a future death every bit as black as the one vividly described by Byron in his marvellous poem, 'Darkness'. No, my argument is that, if we don't want to find ourselves being rendered extinct in the 21st Century, as Prof Sir Martin Rees, the Astronomer Royal, has warned we might be, then we need to start doing things like curbing population growth, reducing greenhouse gas emissions, improving energy efficiency, and developing alternative energy sources - pdq.
My fear is that, by the time the politicians have untwisted their underwear, it may be too late!

Re: Malthus, Bayes and Brandon Carter.

From: Greg Bear
Date: 11/15/2008

I quoted "Darkness" in my first novel, HEGIRA, way back when. Agreed that resources are going to be in a severe pinch--but the problem with setting endpoints and running equations is they must always be amended and updated as the measured organisms--you and me--respond. And we do respond. Looking back at past linear predictions of total world resources collapse, economic failure, starvation, etc.--Club of Rome, Paul Ehrlich, just being a couple of examples--their direst predictions have not come true. Not to say some group of another won't get it right some day! As for populations growing too fast and starving--that's a certainty in regions filled with patriarchalism, war, and political upheaval. It's been with us since human agriculture and civilization began and reset the population dial. My concern is that aid to these troubled countries is already suffering drastically due to the present recession. Which is why I've been beating the drum for decades now against ignorant, parochial leadership and me-first conservatism. Ultimately, failure of outreach and of charity comes back to haunt us and cost us dearly in world crises. And that's where dire predictions begin to make scary sense--after eight years of miserably uninformed, arrogant, inadequate leadership. Strangely, there was something of a bright spot in the administration's program for AIDs in Africa. But of course it was not enough. Malthus may yet have his day. (For contrast, however, read Blish and Knight's brilliant A TORRENT OF FACES.)

Re: Malthus, Bayes and Brandon Carter.

From: patrick
Location:
Date: 11/15/2008

Indeed, if one looks into history, more of the world's populations had it far worse vs those in the last century. Communications technology has, however, made the recent cases of poverty and such more obvious, while at the same time obscuring the historical, as well as discouraging the sense to know of such.

Following all that, it comes to mind whether the OP has 'an axe to grind', mm?

Re: Malthus, Bayes and Brandon Carter.

From: Richard Blaber.
Location: Wellingborough, Northamptonshire, England.
Date: 11/23/2008

Thanks, Greg, for your replies to my comments. You are, of course, right in saying that the Club of Rome got it wrong. Maybe I'm wrong about energy, food and water - but the fact is that it's not a good idea for us to go on burning large quantities of fossil fuels, even if there were limitless supplies of them, given what that does to the climate. And the trouble is, even when the reserves are there geologically, they are not necessarily there geopolitically. Iran, Russia and Venezuela are not exactly pro-Western, are they?

Re: Malthus, Bayes and Brandon Carter.

From: Greg Bear
Date: 11/24/2008

I think all sides can agree on energy independence and utilizing and developing sources other than fossil fuel. That's what puzzles me about the global warming skeptics--they seem politically tone-deaf in the extreme. Ever since Katrina and New Orleans, that boat has sailed. The public heard many experts say New Orleans would be the canary in the coal mine. New Orleans drowned. The public now believes. So--

Why not hook up with the research money sure to come--and multi-task?

Re: Malthus, Bayes and Brandon Carter.

From: patrick
Location:
Date: 11/25/2008

Here's something interesting - and only 1.5 million:

http://physicsworld.com/cws/article/news/36758;jsessionid=3444EED42F71B29C6F4EBACEB898FA98


"Now, however, Hyperion Power Generation  a US company based in New Mexico  has brought the dream of tiny nuclear reactors one step closer with its Power Module. This nuclear reactor  or "battery" as the firm calls it  is not much larger than a hot-tub and could supply thermal energy at a rate of about 70 MW. That could be converted into about 27 MW of electricity, which would be enough to supply about 20,000 US households.

Unlike conventional nuclear power plants, Hyperion's reactor uses uranium hydride, which is essentially enriched uranium metal that has absorbed a large amount of hydrogen. As the uranium nuclei decay by fission, they release neutrons that are slowed down by the hydrogen, which acts as the moderator. The slow neutrons can then split further uranium nuclei and trigger a chain reaction.

No moving parts
The novel feature of the reactor is that the power output is kept steady without the need for any moving parts, flowing water, or human intervention. If the uranium hydride gets too hot, the hydrogen is driven out of the uranium metal and the chain reaction stops. But as the system is sealed, the hydrogen flows back into the uranium when it has cooled, allowing the reaction to restart. The up-shot is that the temperature and concentration of hydrogen stabilize, although if the sealed core is breached for any reason, the hydrogen will escape and fission stops.

Heat from the reaction is removed by liquid metal flowing in pipes with mesh wicks. According to the firm, these sealed systems are about 1000 times better than solid metals in transferring heat. Using these pipes is also an important safety feature because they keeps water, which can act as a moderator and slow down the neutrons (thereby speeding up the chain reaction), well away from the reactor core."

Re: Malthus, Bayes and Brandon Carter.

From: patrick
Location:
Date: 11/25/2008

Whoops, that was 25m. Still, vs hundreds of millions or billions.

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