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Politics : The Environmentalist Thread -- Ignore unavailable to you. Want to Upgrade?

To: Bread Upon The Water who wrote (25167)	9/7/2009 11:03:59 AM
From: Maurice Winn	1 Recommendation Read Replies (1) \| Respond to of 36918

Computer models aren't just flawed, they are biased. The only reason for the model makers to make their models realistic is to have them eventually match reality. But it's like medieval priests making models for why witches needed to be burned at the stake. The desired outcome was a burning at the stake, so the prejudices and biases required to achieve that were built into their models. That's what people generally do when they have an outcome they want. That's why bias is considered unprofessional and recusing of oneself is considering good form. A judge sitting in judgment of somebody who murdered their daughter is likely to have a model in their head with a particular outcome in mind - "Get Him!" A good computer model was how chess works in those models which beat Gary Kasparov at chess. Chess has few moving parts and those parts are stuck on a little chessboard 8 x 8. The models could barely beat Kasparov's pattern formation concepts. The climate computer modelers have a much bigger problem than positioning a few chess pieces on a dinky little 2 dimensional board. Their models are necessarily simplistic and therefore wrong to a greater or lesser degree. We need to watch the models and compare them with reality as it unfolds. When the models match reality over decades, precisely, then they can claim to have a slight resemblance with reality. It's not enough to have a dozen people with PhDs in maths and computer modeling using $10 billion of megatrillion petaflops, impressive as that might be. The proof of the pudding is in the eating. You might recall a recent event in which hugely sophisticated modelers armed with maths PhDs modeled money and markets. Ooops a daisy. It turned out that the companies using those models went bust, more or less. Goldman Sachs no doubt has such models too, but they also have a better model called "the inside track" to the money spigots in Washington. The models were excellent and enriching, until they weren't. <We probably ought be talking about why particular models are either accurate/inaccurrate with respect climate change. > I doubt that we can decipher the model workings as the people developing them have big mental horsepower and whack away at them all day every day. I don't have time for that game. All I can do is see how well their predictions match reality and understand the principles they are trying to model and the likelihood of their models being right. But apparently the models were so hopeless they didn't even have cloud cover in them. That's like modeling traffic flows without including the effect of traffic lights. Traffic flows are fine until somebody turns on the traffic lights. Then there are unnecessary delays everywhere. Mqurice