That reflects my understanding of the state of the DNA evidence against Guede.
Well, I'm not an expert on DNA evidence but just based on common sense, it seems to me that if playing the primary role in a murder and sexual assault reasonably leaves 2 DNA traces in a person's blood stains a 1 trace in the person's privates, it's plausible that playing a secondary role might very well leave no DNA traces in the person's blood and none in their privates.
Of course the DNA traces in other parts of the house are far less interesting since Knox and Sollecito can be expected to have left DNA biological evidence there regardless of whether they played some role in the murder.
So I remain skeptical of your argument but I am happy to consider an authoritative source which says that even someone who plays a secondary role in a murder with a knife is very likely to leave biological traces behind. Do you have such an authority? Or are you just going by your own general knowledge and common sense?
Keep in mind that that does not imply that this is the sum of all DNA evidence Guede left on the scene; when you have already found this much biological evidence, there is no reason to continue searching in order to obtain a comprehensive inventory of every trace left by the suspect.
I disagree. The authorities had every reason to continue searching for DNA evidence since they suspected others besides Guede.
Well, I'm not an expert on DNA evidence but just based on common sense, it seems to me that if playing the primary role in a murder and sexual assault reasonably leaves 2 DNA traces in a person's blood stains a 1 trace in the person's privates, it's plausible that playing a secondary role might very well leave no DNA traces in the person's blood and none in their privates.
The prosecution claimed that more than one person must have been involved in the murder because, they alleged, Kercher was stabbed more times than was likely by a single assailant, and...
Continuing my interest in tracking real-world predictions, I notice that the recent acquittal of Knox & Sollecito offers an interesting opportunity - specifically, many LessWrongers gave probabilities for guilt back in 2009 in komponisto’s 2 articles:
Both were interesting exercises, and it’s time to do a followup. Specifically, there are at least 3 new pieces of evidence to consider:
Point 2 particularly struck me (the press attributes much of the acquittal to the expert report, an acquittal I had not expected to succeed), but other people may find the other 2 points or unmentioned news more weighty.
2 Probabilities
I was curious how the consensus has changed, and so, in some spare time, I summoned all the Conscientiousness I could and compiled the following list of 54 entries based on those 2 articles’ comments (sometimes inferring specific probabilities and possibly missing probabilities given in hidden subthreads), where people listed probabilities for Knox’s guilt, Sollecito’s guilt, and Guede’s guilt:
It’s interesting how many people assign a high-probability to Knox being guilty; I had remembered LW as being a hive of Amanda fans, but either I’m succumbing to hindsight bias or people updated significantly after those articles. (For example, Eliezer says .15 is too high, but doesn’t seem otherwise especially convinced; and later one reads in Methods of Rationality that "[Hagrid] is the most blatantly innocent bystander to be convicted by the magical British legal system since Grindelwald's Confunding of Neville Chamberlain was pinned on Amanda Knox.")
EDIT: Jack graphed the probability against karma:
2.1 Outliers
If we look just at >41% (chosen to keep contacts manageable), we find 12 entries out of 54:
I have messaged each of them, asking them to comment here, describing if and how they have since updated, and any other thoughts they might have. (I have also messaged the first 12 commenters or so, chronologically, with <41% confidence in Knox’s guilt, with the same message.) The commenters:
AngryParsley / Cyan / Daniel_Burfoot / Eliezer_Yudkowsky / GreenRoot / John_Maxwell_IV / LauraABJ / Mario / Matt_Simpson / Morendil / Psychohistorian / Shalmanese / Threads / Unknowns / badger / bentarm / bgrah449 / bigjeff5 / brazil84 / dilaudid / jimmy / kodos96 / lordweiner27 / mattnewport / nerzhin / tut
I look forward to seeing their retrospectives, or indeed, anyone's retrospectives on the matter.