Quadraginta,
When you previously used the phrase “voluminous contributions,” I thought you were referring to my comment #1136, which is long and does treat DNA issues related to both items. I misunderstood your comment #1203, but I now see that you were referring to the posts on signal-to-noise (in retrospect I should have come up with a shorter, clearer explanation of S/N ratios). I was not attempting misdirection, however.
Now I would like to answer your question. Let us consider four possibilities.
RS cut MK cooking RS did not cut MK cooking
MK DNA is present on blade (1) (3)
MK DNA is not present (2) (4)
Let us say (1) that MK did get cut while cooking with RS, and there is DNA present. Then there would be an innocent explanation for the DNA, and nothing ties it to the crime. Now let us say (2) that she did get cut, but no DNA is present. This would be ascribed to someone’s cleaning the knife, but nothing would tie the knife to the crime. Now let us say (3) that she did get cut, and DNA was present. This would favor the prosecution’s case. Finally let us say (4) she did not get cut, and no DNA is present. Thus nothing would tie the knife to the crime.
Here is another way of looking at it. Professor Tagliabracci’s report (
http://www.istitutoaffarisociali.it/...co_forensi.pdf) questions the knife DNA result on page 13, to the best of my ability to understand Italian. I assume he brought this question up at the trial, but I do not have a complete summary of his testimony. Therefore, my interpretation of the defense’s position is that the prosecution’s claim of DNA being present is dubious, and even if the DNA were there, an innocent explanation for it exists. I do not see how the second half of this argument in any way invalidates the first.
I would point out that if Sollecito is not telling the truth, possibilities (3) and (4), it does not necessarily follow that he is lying; the alternative is that he sincerely believes something that is not true (I call this a false memory). The distinction between RS’s possibly speaking falsely and lying is important to make from the point of view of language; whether or not it it important to the case is in the eye of the beholder, IMO. Please let me know if I have not been clear.
Chris