based upon the expectation set upon the observance of subsequent facts, at some later date, ~A could also end up being evidence for B
Here’s a contradiction with A and ~A both being evidence for the same thing. You could tell your spouse “Go up and check if little Timmy went to bed”. Before ze comes back you already have an estimate of how likely Timmy is to go to bed on time (your prior belief). But then your spouse, who was too tired to climb the stairs, comes back and tells you “Little Timmy may or may not have gone to bed”. Now, if both of those possibilities would be evidence of Timmy’s staying up late then you should update your belief accordingly. But how can you do that without receiving any new information?
Yes. I get that. We cannot use A and ~A to update our estimates in the same way at the same time. That’s not the same as saying that it is impossible for A and ~A to be evidence of the same thing. One could work on Tuesday, and the other could work on Friday, depending on the situation. That was my only point: can’t generalize a timeline but need to operate at specific points on that timeline. That goes back to the justification for interning Japanese citizens. If we say ~A just can’t ever be evidence of B because at some previous time A was evidence for B, then we are making a mistake. At some later date, ~A could end up being better evidence, depending on the situation. My point was that a better counterargument to the governor’s justification is to point out that the prospect of naturalized citizens turning against their home country in favor of their country of ancestry presents a very low prior, because the Japanese (and other groups that polyglot nations have gone to war with) have not usually behaved that way in the past. I could be wrong, but it doesn’t have anything to do with updating estimates with a variable and its negation to reach the same probability at the same time. I pretty much agree with what you said, just not the implication that it conflicts in some way with what I said.
I think the brief answer to this point is that it is very important to define the hypothesis precisely, to avoid being confused in the way you describe.
Applying that lesson to Earl Warren, we can say that he failed to distinguish between motive for big-sabotage and motive for little-sabotage. Lack of little-sabotage events is evidence in favor of motive-for-big-sabotage (and for no-motive-to-sabotage: with the benefit of hindsight, we know this was the true state of the world). But unclear phrasing by Warren made it sound like he believed absence of little-sabotage was evidence of motive-to-little-sabotage, which is a nonsensical position.
Given the low probability of big-sabotage (even after incorporating the evidence Warren puts forth), it’s pretty clear that the argument for Warren’s suggested policy (Japanese-American internment) depended pretty heavily on the confused thinking created by this equivocation.
Here’s a contradiction with A and ~A both being evidence for the same thing. You could tell your spouse “Go up and check if little Timmy went to bed”. Before ze comes back you already have an estimate of how likely Timmy is to go to bed on time (your prior belief). But then your spouse, who was too tired to climb the stairs, comes back and tells you “Little Timmy may or may not have gone to bed”. Now, if both of those possibilities would be evidence of Timmy’s staying up late then you should update your belief accordingly. But how can you do that without receiving any new information?
Yes. I get that. We cannot use A and ~A to update our estimates in the same way at the same time. That’s not the same as saying that it is impossible for A and ~A to be evidence of the same thing. One could work on Tuesday, and the other could work on Friday, depending on the situation. That was my only point: can’t generalize a timeline but need to operate at specific points on that timeline. That goes back to the justification for interning Japanese citizens. If we say ~A just can’t ever be evidence of B because at some previous time A was evidence for B, then we are making a mistake. At some later date, ~A could end up being better evidence, depending on the situation. My point was that a better counterargument to the governor’s justification is to point out that the prospect of naturalized citizens turning against their home country in favor of their country of ancestry presents a very low prior, because the Japanese (and other groups that polyglot nations have gone to war with) have not usually behaved that way in the past. I could be wrong, but it doesn’t have anything to do with updating estimates with a variable and its negation to reach the same probability at the same time. I pretty much agree with what you said, just not the implication that it conflicts in some way with what I said.
I think the brief answer to this point is that it is very important to define the hypothesis precisely, to avoid being confused in the way you describe.
Applying that lesson to Earl Warren, we can say that he failed to distinguish between motive for big-sabotage and motive for little-sabotage. Lack of little-sabotage events is evidence in favor of motive-for-big-sabotage (and for no-motive-to-sabotage: with the benefit of hindsight, we know this was the true state of the world). But unclear phrasing by Warren made it sound like he believed absence of little-sabotage was evidence of motive-to-little-sabotage, which is a nonsensical position.
Given the low probability of big-sabotage (even after incorporating the evidence Warren puts forth), it’s pretty clear that the argument for Warren’s suggested policy (Japanese-American internment) depended pretty heavily on the confused thinking created by this equivocation.