Recently, on the main section of the site, Raw_Power posted an article suggesting that we find "worthy opponents" to help us avoid mistakes.
As you may recall, Rolf Nelson disagrees with me about Amanda Knox -- rather sharply. Of course, the same can be said of lots of other people (if not so much here on Less Wrong). But Rolf isn't your average "guilter". Indeed, considering that he speaks fluent Bayesian, is one of the Singularity Institute's largest donors, and is also (as I understand it) signed up for cryonics, it's hard to imagine an "opponent" more "worthy". The Amanda Knox case may not be in the same category of importance as many other issues where Rolf and I probably agree; but my opinion on it is very confident, and it's the opposite of his. If we're both aspiring rationalists, at least one of us is doing something wrong.
As it turns out, Rolf is interested in having a debate with me on the subject, to see if one of us can help to change the other's mind. I'm setting this post up as an experiment, to see if LW can serve as a suitable venue for such an exercise. I hope it can: Less Wrong is almost unique in the extent to which the social norms governing discussion reflect and coincide with the requirements of personal epistemic rationality. (For example: "Do not believe you do others a favor if you accept their arguments; the favor is to you.") But I don't think we've yet tried an organized one-on-one debate -- so we'll see how it goes. If it proves too unwieldy or inappropriate for some other reason, we can always move to another venue.
Although the primary purpose of this post is a one-on-one debate between Rolf Nelson and myself, this is a LW Discussion post like any other, and it goes without saying that others are welcome and encouraged to comment. Just be aware that we, the main protagonists, will try to keep our discussion focused on each other's arguments. (Also, since our subject is an issue where there is already a strong LW consensus, one would prefer to avoid a sort of "gangup effect" where lots of people "pounce" on the person taking the contrarian position.)
With that, here we go...
Reply to: http://lesswrong.com/r/discussion/lw/6k7/experiment_knox_case_debate_with_rolf_nelson/4jmb
Didn't realize you updated, looks like we can't go more than 8 or 9 deep before the RSS feed stops notifying about thread changes.
In terms of narrowing down what Umani Ronchi was actually saying, saying that the prosecution claims something in its appeals document isn't useful evidence. If there's a specific quote of Umani Ronchi that the prosecution makes, that might be useful, as long as the quote is clear enough that we can deduce it isn't being quoted out-of-context.
That's a good find, and you may be right. I was going by this, but maybe it's a mistranslation or a misunderstanding:
"[Introna] also observed that the beginning of the attack must have been a moment of tremendous stress for Kercher and may have arrested the digestive process. One could and should obtain a precise indication from this, in the sense that the stress to which the victim was subjected must have started between 21:30 pm and 22:30 pm." (p. 130)
Again, post-trial prosecution claims that haven't even gone under cross-examination aren't useful evidence. If you want an alibi to 21:30, you'll have to provide better support, which will unfortunately be difficult even if Raffaele is innocent, since computers open files in the background all the time, and so not just the timing but the nature of the file opened will have to be examined.
There's evidence of about one glass (p. 152), so around 10 ml. A dose of 60 ml appears to almost double emptying time in one study (http://alcalc.oxfordjournals.org/content/40/3/187.full.pdf+html), so I'd expect a change of about 10-20% in Meredith's case. So probably not terribly significant on its own. I know there was no trace of drugs found in her body, and marijuana appears to have a long half-life, so I agree there's no drug consumption even though Meredith had easy access to marijuana.
So to get to even 21:00 from 18:00, you need to go out by more than 90 minutes. Three standard deviations is >.99 probability, so this model doesn't seem to be accurate, at least not with a normal distribution. So do you want to propose a new model with a greater standard deviation, or propose that it's not a normal distribution? If the latter, I would expect the deviation from normality to be equally likely to work against Raffaele, as it is to work in his favor.
In the other direction, a 30-minute variance is already too large to provide much evidence in favor of Raffaele's innocence, especially without further evidence of a 21:30 alibi.
I agree that the stomach findings are a mild surprise if we're talking about 23:00+ like in the Massei narrative, but the first problem is that my surprise is only mild since there are so many factors that affect it, and the second problem is that once I'm slightly surprised by going out to 21:00, I don't get much more surprised by going out to 21:30 or even 22:00, and so don't see Raffaele as having an alibi.
As an example, does it surprise you that the abstract of one (unfortunately gated) study (http://www.ncbi.nlm.nih.gov/pubmed/7956593) of fried food gives 317 minutes for total gastric emptying, even though it probably, like other experiments, is unlike Meredith's case in that it probably involves pre-experiment fasting and no post-meal snack.
I don't follow the logic here; isn't the more important question whether the stomach contents could have equally well constituted just half or 2/3 the meal? Or do you just mean that it's unlikely more than half of the meal passed through?
Yes, your model (if correct) of a non-ligature situation harms the court's theory about the attack taking place somewhere in the 23:00-23:30 interval, though it fails again to save Raffaele's computer alibi. Plus, I think you're underestimating the quantitative level of uncertainty if we don't know how much she ate, exactly what all she ate, exactly when she started eating, what effect having a post-meal snack has, what effect not fasting has, amount of alcohol consumed, and what effect walking home after eating had, all of which should contribute to a large standard deviation.
Surely you meant the defense appeal document here? (I haven't referenced the prosecution appeal, and there wouldn't be much reason to, since it's just a 20-page rant arguing that Amanda and Raffaele are really nasty people and deserve a harsher sentence than the Massei court gave them.)
My interpretation of Ronchi doesn't depend on the defense appeal; it's simply the common-sense default meaning of w... (read more)