# cousin_it comments on Inherited Improbabilities: Transferring the Burden of Proof - Less Wrong

28 24 November 2010 03:40AM

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Comment author: 25 November 2010 01:23:01AM *  6 points [-]

I'm not sure if I understand the post completely. Is the following a fair translation?

"If our prior against Knox's guilt is 1:1000000, and a staged burglary would imply with 99% certainty that Knox is guilty, and we have 1000:1 evidence that the burglary was staged, then mathematically this isn't enough to convict Knox. You need more evidence."

(For some reason the post is much longer than that, and makes all those arguments whose purpose I don't understand...)

Comment author: 25 November 2010 03:22:29AM 8 points [-]

(For some reason the post is much longer than that, and makes all those arguments whose purpose I don't understand...)

Such as....?

Yes, the point is a mathematical triviality. For that matter, so is Bayes' theorem itself. That doesn't mean that everybody grasps its implications at once, so that it isn't worth writing detailed posts on.

Comment author: 25 November 2010 01:33:51AM 5 points [-]

Pretty much, I think.

If the prior P(guilty) is 1:1000000 and P(guilty|staged) is really high, a consistent prior requires that P(staged) is around 1:1000000 as well. Therefore 1000:1 evidence isn't enough.