If you change your story, the probability of your guilt is 1.00.
This is equivalent to stating “no innocent person ever changes their story.” Empirically, this is false.
Let me provide a personal example. Several years ago, I was nearby when a co-worker was injured on the job. Two years later, I received a summons—she had ended up suing the company, and as an eyewitness, my testimony was relevant. Lawyers for the two parties asked me questions for a while; I answered to the best of my ability, as honestly as I could. My memory of the event was somewhat fuzzy by then, so I tried to only state things which I was sure I remembered accurately, and expressed my uncertainty when I was uncertain.
Once they finished their questions, they handed me a photocopy of a document in my own handwriting, written on the day of the event. The company had gotten such statements from everyone present on the day of the incident, you see. Not only had I forgotten that I had written such a thing until they showed it to me, my own handwriting directly contradicted the things I’d stated from memory minutes before!
This was before I participated in Less Wrong or was otherwise aware of the breadth of human cognitive failings. I was quite taken aback! My brain had betrayed me—not in old age, in my early twenties! I do not generally consider myself forgetful—if anything, I have an unusually good memory—yet in a fairly short span of time, my brain had managed to confabulate almost every detail of the event.
Since I became aware of it, I’ve noticed myself mid-confabulation on a regular basis. Despite how much my conscious mind values truth, my underlying hardware doesn’t seem to much care.
You may indeed be one of the lucky people with flawless recall. This is not, by a long shot, a universal human trait. Memory is fragile. It is quite easy for many humans to misremember things without knowing anything has gone wrong, especially when under significant amounts of stress.
I know very little of the Amanda Knox case specifically, so this should not be taken as an argument for either side particularly. I am only arguing that your simple rule is not a good rule—it doesn’t actually work.
Your example is a good one—of memory change across a period of two years. From work I’ve done on a family history based on my own recollections, recollections from other persons, and the occasional bit of documentary evidence, I know I don’t have “flawless recall,” but that strikes me as a bit of a straw man. In fact, I will mention, in passing, that I have been favorably impressed, in the course of the project, by the number of decades-old recollections that comport—or very-nearly comport—with surviving documentation. On one or two occasions, an erroneous memory has been interestingly explained. A family member recalls, for instance, that a photograph was taken on a date that a relative moved out of a residence, but the photograph itself is seen to be dated three years before the relative’s departure from that place. At some point, somebody else’s recollection reveals that the photograph was taken on the day a visitor to the residence left it, to go home. The false memory, in other words, included an association with the word “departure.”
It’s a matter of the details of the story-changing. I haven’t read all of Knox’s statements to the investigators and don’t know the dates on which each of them was made. They appear to have been made within a few days of the murder; and at least one of them seems to have included the following false statement, about the man named Lumumba: “I confusedly remember that he killed her [Kercher].”
The utterance of such a false thing, outside, maybe, a literal torture chamber, is depraved.
The utterance of such a false thing, outside, maybe, a literal torture chamber, is depraved.
That may be so!
This is quite different from being a literally perfect indicator of guilt. I’d feel overconfident saying there was a 95% chance I could keep my story straight if accused of murder, never mind in another country and another language.
Part of this may be calibration. 2.00 obviously isn’t even a probability, but even if I assume your 1.00 figure is simply rounded to two decimal places, it would require that less than one person in one hundred who changes their story is actually innocent. I doubt that is the case.
This is equivalent to stating “no innocent person ever changes their story.” Empirically, this is false.
Let me provide a personal example. Several years ago, I was nearby when a co-worker was injured on the job. Two years later, I received a summons—she had ended up suing the company, and as an eyewitness, my testimony was relevant. Lawyers for the two parties asked me questions for a while; I answered to the best of my ability, as honestly as I could. My memory of the event was somewhat fuzzy by then, so I tried to only state things which I was sure I remembered accurately, and expressed my uncertainty when I was uncertain.
Once they finished their questions, they handed me a photocopy of a document in my own handwriting, written on the day of the event. The company had gotten such statements from everyone present on the day of the incident, you see. Not only had I forgotten that I had written such a thing until they showed it to me, my own handwriting directly contradicted the things I’d stated from memory minutes before!
This was before I participated in Less Wrong or was otherwise aware of the breadth of human cognitive failings. I was quite taken aback! My brain had betrayed me—not in old age, in my early twenties! I do not generally consider myself forgetful—if anything, I have an unusually good memory—yet in a fairly short span of time, my brain had managed to confabulate almost every detail of the event.
Since I became aware of it, I’ve noticed myself mid-confabulation on a regular basis. Despite how much my conscious mind values truth, my underlying hardware doesn’t seem to much care.
You may indeed be one of the lucky people with flawless recall. This is not, by a long shot, a universal human trait. Memory is fragile. It is quite easy for many humans to misremember things without knowing anything has gone wrong, especially when under significant amounts of stress.
I know very little of the Amanda Knox case specifically, so this should not be taken as an argument for either side particularly. I am only arguing that your simple rule is not a good rule—it doesn’t actually work.
Your example is a good one—of memory change across a period of two years. From work I’ve done on a family history based on my own recollections, recollections from other persons, and the occasional bit of documentary evidence, I know I don’t have “flawless recall,” but that strikes me as a bit of a straw man. In fact, I will mention, in passing, that I have been favorably impressed, in the course of the project, by the number of decades-old recollections that comport—or very-nearly comport—with surviving documentation. On one or two occasions, an erroneous memory has been interestingly explained. A family member recalls, for instance, that a photograph was taken on a date that a relative moved out of a residence, but the photograph itself is seen to be dated three years before the relative’s departure from that place. At some point, somebody else’s recollection reveals that the photograph was taken on the day a visitor to the residence left it, to go home. The false memory, in other words, included an association with the word “departure.”
It’s a matter of the details of the story-changing. I haven’t read all of Knox’s statements to the investigators and don’t know the dates on which each of them was made. They appear to have been made within a few days of the murder; and at least one of them seems to have included the following false statement, about the man named Lumumba: “I confusedly remember that he killed her [Kercher].”
The utterance of such a false thing, outside, maybe, a literal torture chamber, is depraved.
That may be so!
This is quite different from being a literally perfect indicator of guilt. I’d feel overconfident saying there was a 95% chance I could keep my story straight if accused of murder, never mind in another country and another language.
Part of this may be calibration. 2.00 obviously isn’t even a probability, but even if I assume your 1.00 figure is simply rounded to two decimal places, it would require that less than one person in one hundred who changes their story is actually innocent. I doubt that is the case.