Less Wrong is a community blog devoted to refining the art of human rationality. Please visit our About page for more information.

Eliezer_Yudkowsky comments on The Amanda Knox Test: How an Hour on the Internet Beats a Year in the Courtroom - Less Wrong

42 Post author: komponisto 13 December 2009 04:16AM

You are viewing a comment permalink. View the original post to see all comments and the full post content.

Comments (632)

You are viewing a single comment's thread. Show more comments above.

Comment author: Eliezer_Yudkowsky 19 December 2009 02:47:30AM 2 points [-]

The case against Knox and Sollecito is weak because it is weak, not because the case against Guede is strong.

That's why I keep on saying not to compare the amount of evidence against Guede to the case against Knox. It's not a comparison operation. It doesn't set a bar. It doesn't set a standard. Now, the fact that Guede left a lot of DNA means it's implausible that Knox cleaned up only her DNA and not Guede's, but that's a whole separate issue. And the fact that we know Guede did it means that there's no unexplained murder around for Knox to be convicted of. But under other circumstances, it would be very easy to have a murder that was in fact committed by two people, one of whom left very strong evidence against herself, and one of whom left less strong but still conviction-worthy evidence against herself. It's just not a relative operation.

Comment author: komponisto 19 December 2009 03:26:17AM *  1 point [-]

Okay, I agree that ideal rational agents with unlimited computing resources shouldn't "care" about the relative strength of evidence; all they have to do is perform the appropriate computation, and the result will come out to whatever it should be. But I've already conceded that "follow the strong signal" is a heuristic for human use, in order to get results that, in reality, better approximate what an ideal rational agent would come up with than the methods that are already programmed into us.

The situation we're in is the following: we're investigators on a budget, trying to figure out how to allocate our limited resources among various paths through hypothesis space. Let's say there are two particular paths we're considering, and at the entrance to each of them is a loudspeaker with a voice saying "FOLLOW THIS TRAIL". Except that one of the voices is twice as loud as the other. Now, am I completely crazy, or is it not an epistemically reasonable thing to do to do something like allocate twice the investigative resources to following the signal that is twice as strong? How else should we divide it up?

I don't think I need to remind you that reality is consistent: if Knox was really involved in a conspiracy with Guede, then the Knox trail will meet up with the Guede trail, in which case we're not losing anything by devoting the lion's share of our resources to starting along the Guede trail rather than the Knox trail.

What, if anything, am I missing here?

Comment author: Eliezer_Yudkowsky 19 December 2009 04:46:32AM 2 points [-]

The problem is that finding Guede's semen inside Meredith is not evidence against the hypothesis "Guede and Knox murdered Meredith". Guede's already been caught, too. So now the question is whether to devote any of our remaining attention to trying to catch Knox, and the insufficient/disconfirmatory evidence for this fails to surpass the prior implausibility of the conspiracy hypothesis - it has nothing to do with how hard Guede was caught.

Comment author: erica 19 December 2009 10:11:24AM 0 points [-]

Are you sure semen was found? I've read elsewhere this was a manual rape - still leaves DNA inside but not necc. semen.

Comment author: Eliezer_Yudkowsky 19 December 2009 06:06:16PM 0 points [-]

Nope, not sure offhand.

Comment author: wedrifid 19 December 2009 10:30:36AM 0 points [-]

I've read elsewhere this was a manual rape - still leaves DNA inside but not necc. semen.

Manual rape? I'm not familiar with that term and a meaning fitting those criteria (DNA but not semen) isn't obvious. I can only assume that 'manual' refers to, well, the last part of it. I wouldn't have expected that kind of rape if murder was going to be on the cards and I would also expect semen around somewhere, showing up with luminol. So perhaps something else is meant.

Comment author: anonym 19 December 2009 09:18:11PM 2 points [-]

One meaning of 'manual' is 'of or relating to the hands'. I'm guessing that's what's meant here.