This quote is attributed, perhaps spuriously to Keynes. A sharper version of the same point is made here by Noah Smith, exploring the concept “Derp”, “”the constant, repetitive reiteration of strong priors”, where “strong priors” in the technical Bayesian sense, mean that ” … you really, really believe something to be true. If your start off with a very strong prior, even solid evidence to the contrary won’t change your mind. ”
A notable example of this, very relevant on this blog, and cited by Smith, is the cost of solar energy. Roughly speaking, the cost of solar modules has fallen by a factor of 10 over the past few years, and the cost of installed systems by a factor of three. If that hasn’t changed your mind about the relative merits of alternative policy option, then you must have really strong priors, and in that case, you shouldn’t be engaging in debate, since your mind can’t be changed by evidence. As Smith observes, “That is unhelpful and uninformative, since they’re just restating their priors over and over. Thus, it is annoying. Guys, we know what you think already.”
But, it’s easy to throw stones, so I thought I would check my own archives to see if I was guilty of Derping on this point. Here is what I thought in 2004
Nuclear (fission) power is probably the cheapest large-scale alternative electricity source (there are some sites where wind is cost-competitive, and similarly for geothermal) but it is still a good deal more expensive than coal or gas. How much more expensive is hard to tell because the industry is riddled with subsidies, but I’d guess that the full economic cost is about twice as high for nuclear electricity as for coal or gas. Moreover, most recent construction has been in places like China and Korea where safety standards may not be as high as they would have to be to get nuclear energy restarted in the developed world as a whole.
What this means is that nuclear power won’t enter into calculations until we have a carbon tax (or equivalent) steep enough to double the price of electricity. It’s clear though, that much smaller increases in costs would make a wide range of energy conservation measures economically viable, as well as reducing final demand for energy services. Implementing Kyoto, for example, would not require anything like a doubling of prices. Whether or not a more radical response is justified, it’s clearly not going to happen for at least a decade and probably longer.
Nevertheless, if mainstream projections of climate change turn out to be correct, and especially if, as Lovelock suggests, they turn out to be conservative, we’ll eventually face the need for new sources of electricity to replace fossil fuels. Solar photovoltaics are improving fast but still a long way from being cost-competitive. So it may well be that, at least for an interim period, expansion of nuclear fission is the best way to go.
I didn’t mention carbon, capture and storage, but I also supported that as a good option for Australia, assuming it could me made to work.
The facts have changed, and I have changed my mind. I now think the role of renewables, and particularly solar is going to be much larger than seemed likely ten years ago, nuclear much less, and CCS marginal.
Update Obviously, this post was intended to provoke a reaction from the critics of renewable energy (normally, also advocates of nuclear) who regularly comment here, challenging them to say how they had adjusted their views in the light of the evidence of the last decade. Most commenters responded thoughtfully. But our single-topic nuclear fans, Hermit and Will Boisvert, responded by herping even more flerps of derp. Despite being reminded of the topic, they just kept on pumping out the same constant, repetitive reiteration of their priors that defines derp. This does, at least provide me with some guidance. From now on, comments from single-issue pro-nuclear commenters (specifically, the two mentioned) will be deleted unless they contain a point that has not been made previously or (highly improbably) a change of view.
John Quiggin 
But if pellets fall out from overheating then they gather at the bottom and do not need moderator/ enabler anymore. They are close enough to keep fission going.
But i think that it was not reactors that presented main problems at Fukushima, it was spent fuel rod pools that caused the problems that initiated the chain reaction events that led to explosions.
The earthquake itself shook the open pools and crushed some fuel rods causing pellets to fall out and gather at the bottom. The intensity of the quake also spilled over some watter out of the pools contaminating the whole buildings forcing managers to evacuate and let happen what did happen.
Reactor housings have hydrogen exhaust valves but buildings themselves that housed spent fuel pools did not which caused the explosions of the structures themselves with reactor housing intact.
It was the fact that reactor housings were left intact while the building around it exploded changed my thinking that reactors themselves were the initial problem at the Fukushima.
@ Rog, on Fukushima causing a “demonic chain reaction” that destroys Tokyo:
“’A demonic chain reaction…we sould lose Fukushima Daini, then we would lose Tokai…we would also lose Tokyo’…the politicians did identify a worst case scenario.”
Rog, you call that a worst case scenario? You forgot to add Godzilla rising from the sea and mutant cannibal zombies descending on Tokyo.
The scenario you cite, from a Japanese politician, is idiotic: Radiation levels at Fukushima rise so high that the plant must be evacuated; radioactive plumes from Fukushima then flow unimpeded to other nuclear power plants, which are likewise evacuated because of radiation risks and go into their own meltdowns, spewing more plumes to flow to other plants which are also abandoned and go into meltdown, ad nauseam.
This is all nonsense on stilits. (That’s why, according to your Times article, the people actually at Fukushima Daiichi argued strenuously against evacuating anyone from the plant; they knew perfectly well that the dangers there were modest.) The only thing this doom-mongering shows is how deeply entrenched anti-nuclear mythologies are in everyone from know-nothing bloggers to know-nothing cabinet ministers.
We can see how absurd the scenario is by looking at the actual data on radiation exposures at the Fukushima Daiichi plant, which were laughably short of anything that could require evacuation. According to the World Health Organization report, of the 23,000 wokers at Fukushima Daiichi in the months during and after the spew, 16,000 received a dose of 10 millisieverts or less, which would cause all of 9 fatal cancers over a lifetime. The remaining 7000 workers got an average dose of 30 msv, for 12 fatal cancers over a lifetime. 75 workers got a dose from 100-700 msv, 700 msv being the maximum anyone received; if all 75 had received that dose, a vast overestimate, it would result in 3 fatal cancers in addition to the 15 that would normally be observed.
So the risk of dying from the radiation at the Fukushima Daiichi plant was much less than one in a thousand overall for workers during the spew, rising to at most 4 percent for the most exposed individual. Such tiny mortality risks are much smaller than those for many dangerous occupations like fishermen and loggers.
And those were the exposures and risks for workers right at the stricken plant, ground zero of the spew. A fallout plume flowing to some other nuclear plant would have been attenuated by hundreds of times. Even if the Fukushima spew had been many times larger than it actually was, by the time plumes reached other nuclear plants miles away the radiation would have been far too low to present any appreciable risk or warrant evacuation.
So the notion of a “demonic chain reaction” of meltdowns and abandonments is barking, howling lunacy; nothing but the panicky raving of sleep-deprived men who had no understanding of the situation other then what we have all gleaned from radiophobic Hollywood thrillers. Fortunately, cooler heads prevailed; an evacuation of Tokyo would surely have killed thousands of sick people just from the stress of relocation. (600 people died in the Fukushima evacuation.)
Fukushima proved once again that nuclear power is quite safe–even when it melts down and blows up. The real threats we face are ignorance, superstition and the irrational ideologies they feed.
@ Rog, on the stupidity of using worst-case scenarios as a guide.
Rog, if you think for half a minute you’ll realize that it’s stupid to use worst-case scenarios as a guide for policy, and that people never do.
It’s possible that tomorrow Al Qaeda will hijack hundreds of airliners and crash them all into skyscrapers, killing millions of people. Should we therefore abolish air travel, or force every airline to carry trillions of dollars of insurance against that scenario?
It’s possible that tomorrow during rush hour 50 million drivers in the US will crash their cars and die. Should we therefore abolish automobiles or reduce the speed limit to 5 miles per hour to forestall that scenario?
It’s possible that tomorrow a meteor will hit Tokyo and kill the 30 million people in it. Should we therefore evacuate Tokyo as a precautionary measure, or rebuild it 2 miles underground to shield it from meteors?
The article you linked to about worst cases and Fukushima was unintentionally funny. It noted a sign above the Fukushima plant marking the high water from an ancient tsunami, and warning never to build below that; if only TEPCO had heeded that warning! The irony is that Japan is currently rebuilding all the seaside communities that were destroyed by the recent tsunami—where they will be vulnerable to the next tsunami. No one ever suggests thats Japan simply ban settlement in coastal areas, even though 16,000 people died from the tsunami in those places. But people do suggest that we ban nuclear power because of the Fukushima spew, even though there will be no observable casualties at all from Fukushima radiation.
So all the dudgeon about worst-case scenarios is silly. People and governments never, absolutely never, base their behavior or planning on worst case scenarios, not even the “predictable” ones, and especially not the sort of absurdities of the anti-nuclear alarmists. Only madmen and propagandists tremble at worst cases. The rest of us look at history and science to assess risks, balance them against benefits, prepare for plausible rather than imaginary threats and get on with life. People who apply that common sense approach to nuclear power usually decide that we need a lot more of it.
@ Fran Barlow;
Thanks for the link to that CarbonBrief piece on the Energiewende. I must say, though, that it was little better than a press release, entirely one-sided and lacking in critical analysis.
Its discussion of the costs of the Energiewende, for example, misrepresented the sources it cited. Carbon Brief disputes a 1 trillion dollar cost estimate for the Energiewende by citing a figure of 200 billion euros from Businessweek, but the Businessweek article itself says that that is the cost just for offshore wind turbines and associated transmission—just a small part of the Energiewende’s total costs. Similarly, CarbonBrief cites an MIT Technology Review article number of 100-200 billion euros, but fails to note that this is just a partial figure and that the total costs “will be far higher,” according to the article.
Unfortunately, such sketchy, one-sided and borderline fraudulent treatments are the rule in the green literature on the Energiewende. If you are interested in a much more detailed and critical study of the Energiewende’s costs and performance, you could start with my recent Dissent magazine piece here. http://www.dissentmagazine.org/article/green-energy-bust-in-germany
As for my green urbanism piece at In These Times, you describe it as “mythology,” although “not entirely ridiculous” (just mainly ridiculous, I guess); and you say that you “support urban consolidation for many of the reasons [I] cited in [my] article” and yet still find the piece “either lazy or disingenuous” (at least it’s not both!) So I’m confused as to exactly what your attitude is toward the piece, and why.
You are right that Manhattan has a hinterland supplying it, but you need to apply that to both sides of the low-density/high-density divide. An isolated farmstead in Vermont also has a hinterland stretching across the globe, encompassing things like Mexican auto plants to build the SUV and Indonesian rubber plantations to supply the tires, British Columbian forests to supply the wood for a rambling house, North Dakota heating oil, Chinese factories and mines to produce the washer-dryer set that usually sits idle, etc. Because the typical Manhattanite is so much more sparing in her consumption of housing, transportation, energy and consumer goods, her hinterland is much smaller than the typical Vermonter’s.
Of course, the world still needs farmers and miners and loggers, so you’re right that we can’t all live in cities. But most other people in industrial or service or symbol analyst jobs actually could live in cities, especially in the US where only a tiny fraction of the population makes its living from the land. That would be a lot more sustainable than the diffuse suburban and exurban sprawl where most Americans live.
@Will Boisvert
““’A demonic chain reaction…we sould lose Fukushima Daini, then we would lose Tokai…we would also lose Tokyo’…the politicians did identify a worst case scenario.”
Rog, you call that a worst case scenario? You forgot to add Godzilla rising from the sea and mutant cannibal zombies descending on Tokyo.”
As other commenters have pointed out, you seem to have no ability to discern real threats from commercial fictional threats. As with the holocaust that you referred to dismissively on J W Mason’s blog – real horrors require the proper regard. You seem to lack proper regard for the sufferings of others.
“You are right that Manhattan has a hinterland supplying it, but you need to apply that to both sides of the low-density/high-density divide”
Manhattan has a very high footprint when you factor in consumption, including aeroplane travel etc . You have no capability for critical discernment Will Boisvert.
Will – it’s being worked on incrementally.
@ Fran Barlow #5 above, that should be “CarbonBrief disputes a 1 trillion euro cost estimate for the Energiewende…” Apologies.
Good to see Will Boisvert make an apology.
Bang on cue the boss of the beleaguered Tepco has some advice
You have to give him his due, he does have some experience of the nuclear industry.