She’s a model and she’s looking good, or how to spot a model that actually works

Tom Quirk has an article in right of centre magazine Quadrant pouring cold water on climate change modelling by arguing that, after all, it’s just a model.

I think there’s some sense in this, if only it wasn’t being said by people who are just looking for another reason to tell us climate change mitigation is costly for rich people everyone. Junk in, junk out, right? But let’s take the argument a bit further than that. Indeed, what else could usefully be described as ‘just a model’?Douglas Rushkoff  points out that the economy is just a model, and we’d better not forget it. This seems to have implications of which the folk at Quadrant might not entirely approve.

The first step, of course, is to remember that the economy itself is just a model. It’s a way of understanding the world as a series of transactions made by rational, self-interested beings working to maximize value for themselves. That’s supposedly the given. Of course, it isn’t even true. We don’t live in an economy. Never did.

I think this ‘just a model‘ idea is fashionable and could spread. For instance, next time I’m in the shop with my son and the checkout attendant asks him to pay for his new Hotwheels acquisition, I’ll chime in with ‘Lay off the kid,  it’s just a model!’ If it works for Quadrant

Actually, it’s not fashionable. It’s nearly 40 years old. When the groundbreaking modelling conducted for the Club of Rome was published in 1972 under the title The Limits to Growth, it was widely misinterpreted as claiming ‘if present trends continue, we won’t’. Critics of the report said – you  guessed it – it’s just a model. As far as some were concerned, no model (and indeed no evidence) could ever show that limits to growth exist, since the phrase itself is an oxymoron. In fact it’s usually the modellers themselves who are clearest and most vocal that it’s just a model. But it rarely helps, since opponents just quote their words right back at them to demonstrate that it’s really just a model.

You might like to watch or listen to Dr Graham Turner of CSIRO summarising some research showing how the ‘business as usual’ model (just a model, remember) actually tracked subsequent reality rather well.

Audio: Examining the Limits to Growth


Graham M. Turner. A Comparison of The Limits to Growth with 30 years of reality. Global Environmental Change 18 (2008) 397-411. (or working paper)

But of course, there’s no such thing as just a model…

(I’d forgotten about how in the late 1970s the West German ‘economy’ was doing so poorly that it resorted to forcing the unemployed to pretend to play keyboards if they wanted to receive welfare payments. We knew them as Kraftwerk, which in retrospect was just a smokescreen for Machtwerk. There were clearly far too many of them and the job satisfaction was awful. Wouldn’t you look that glum if it happened to you?)


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