One of the most useful techniques of rationality is taking the outside view, also known as reference class forecasting. Instead of thinking too hard about particulars of a given situation and taking a guess which will invariably turned out to be highly biased, one looks at outcomes of situations which are similar in some essential way.
Figuring out correct reference class might sometimes be difficult, but even then it's far more reliable than trying to guess while ignoring the evidence of similar cases. Now in some situations we have precise enough data that inside view might give correct answer - but for almost all such cases I'd expect outside view to be as usable and not far away in correctness.
Something that keeps puzzling me is persistence of certain beliefs on lesswrong. Like belief in effectiveness of cryonics - reference class of things promising eternal (or very long) life is huge and has consistent 0% success rate. Reference class of predictions based on technology which isn't even remotely here has perhaps non-zero but still ridiculously tiny success rate. I cannot think of any reference class in which cryonics does well. Likewise belief in singularity - reference class of beliefs in coming of a new world, be it good or evil, is huge and with consistent 0% success rate. Reference class of beliefs in almost omnipotent good or evil beings has consistent 0% success rate.
And many fellow rationalists not only believe that chances of cryonics or singularity or AI are far from negligible levels indicated by the outside view, they consider them highly likely or even nearly certain!
There are a few ways how this situation can be resolved:
- Biting the outside view bullet like me, and assigning very low probability to them.
- Finding a convincing reference class in which cryonics, singularity, superhuman AI etc. are highly probable - I invite you to try in comments, but I doubt this will lead anywhere.
- Or is there a class of situations for which the outside view is consistently and spectacularly wrong; data is not good enough for precise predictions; and yet we somehow think we can predict them reliably?
How do you reconcile them?
It doesn't. I simply don't believe in Reference Class Tennis. Experiments show that the Outside View works great... for predicting how long Christmas shopping will take. That is, the Outside View works great when you've got a dozen examples that are no more dissimilar to your new case than they are to each other. By the time you start trying to predict the future 20 years out, choosing one out of a hundred potential reference classes is assuming your conclusion, whatever it may be.
How often do people successfully predict 20 years out - let alone longer - by picking some convenient reference class and saying "The Outside View is best, now I'm done and I don't want to hear any more arguments about the nitpicky details"?
Very rarely, I'd say. It's more of a conversation-halter than a proven mode of thinking about that level of problem, and things in the reference class "unproven conversation halter on difficult problems" don't usually do too well. There, now I'm done and I don't want to hear any more nitpicky details.
It also depends on which aspects of the future one is trying to predict... I'll go out on a limb here, and say that I think the angular momentum of the Earth will be within 1% of its current value 20 years out.