However, I think you misunderstood what I was attempting to say. I see I didn’t use the term “filtered evidence”, and am wondering if my comment showed up somewhere other than the article “what evidence filtered evidence”:
http://lesswrong.com/lw/jt/what_evidence_filtered_evidence/
Explaining how I got a response so quickly when commenting on a 5 year old article!
If so, my mistake as my comment was then completely misleading!
When the information does not come from a filtered source, I agree with you.
If I find out that there is evidence that will be in the up (or down) direction of a belief, this will modify my priors based on the degree of entanglement between the source and the matter of the belief.
After seeing the evidence then the probability assessment will on average remain the same; if it was weaker/stronger it will be lower/higher (or higher/lower, if evidence was downward) but it will of course not pass over the initial position before I heard of the news, unless of course it turns out to be evidence for the opposite direction.
What my question was about was filtered evidence.
Filtered evidence is a special case, in which that entanglement between the source and matter of the belief = 0.
Using Eliezer_Yudkowsky's example from "the bottom line":
http://lesswrong.com/lw/js/the_bottom_line/
The only entanglement between the claim of which sort of evidence I will be presented with, “box B contains the diamond!”, is with whether the owner of box A or box B bid higher (owner of box B, apparently).
Not with the actual content of those boxes (unless there is some relation between willingness to bid and things actually entangled with presence/absence of a diamond).
Therefore, being told of this will not alter my belief about whether or not box B is the one that contains the diamond.
This is the lead-in to the questions posed in my previous/first post.
Knowing that the source is filtered, every single piece of evidence he gives you will support the conclusion the diamond is in box B. Yet you simply cannot expect every single piece of evidence to on average increase your belief that it is in box B.
While the arguments are actually entangled, their selective presentation means P(E)=1 and P(~E)=0.
You can’t balance the equations other than by not modifying your beliefs at all with each piece of evidence.
Probability of the diamond being in box B = probability of the diamond being in box B given that you are shown evidence, meaning the evidence doesn’t matter.
The direction of the evidence that passes through the filter (the clever arguer) is entangled with which box-owner bid more money. Not with which box actually contains the diamond.
Thus, it sounds like you simply should not modify your beliefs when faced with a clever arguer who filters evidence. No entanglement between evidence’s direction and the truth/conservation of expected evidence.
My problem: not taking into account evidence entangled with reality doesn’t sit well with me. It sounds as though it should ultimately be taken into account, but I can’t immediately think of an effective process by which to do it.
Using drugs instead of boxes if that is an example you prefer: imagine a clever arguer hired by Merck to argue about what a great drug Rofecoxib is. The words “cardiovascular”, “stroke”, and “heart attack” wont ever come up.
With the help of selectively drawing from trials, a CA can paint a truly wonderful picture of the drug that has limited baring on reality.
Before seeing his evidence he tells you “Rofecoxib is wonderful!” This shouldn’t modify your belief, as it only tells you he is on Merck’s payroll.
Now how do you appropriately modify your belief on the drug’s quality and merits with the introduction of each piece of evidence this clever arguer presents to you?
Actually, it’s my bad—I found your comment via the new-comments list, and didn’t look very closely at its context.
As to your actual question: Being told that someone has evidence of something is, if they’re trustworthy, not just evidence of the thing, but also evidence of what other evidence exists. For example, in my scenario with gwern’s prank, before I’ve seen gwern’s web page, I expect that if I look the mentioned drug up in other places, I’ll also see evidence that it’s awesome. If I actually go look the drug up and find out that it’s no better than placebo in any situation, that’s also surprising new information that changes my beliefs—the same change that seeing gwern’s “April Fools” message would cause, in fact, so when I do see that message, it doesn’t surprise me or change my opinion of the drug.
In your scenario, I trust Merck’s spokesperson much less than I trust gwern, so I don’t end up with nearly so strong of a belief that third parties will agree that the drug is a good one—looking it up and finding out that it has dangerous side effects wouldn’t be surprising, so I should take the chance of that into account to begin with, even if the Merck spokesperson doesn’t mention it. This habit of keeping possible information from third parties (or information that could be discovered in other ways besides talking to third parties, but that the person you’re speaking to wouldn’t tell you even if they’d discovered it) into account when talking to untrustworthy people is the intended lesson of the original post.
Thanks for the response.
However, I think you misunderstood what I was attempting to say. I see I didn’t use the term “filtered evidence”, and am wondering if my comment showed up somewhere other than the article “what evidence filtered evidence”: http://lesswrong.com/lw/jt/what_evidence_filtered_evidence/ Explaining how I got a response so quickly when commenting on a 5 year old article! If so, my mistake as my comment was then completely misleading!
When the information does not come from a filtered source, I agree with you. If I find out that there is evidence that will be in the up (or down) direction of a belief, this will modify my priors based on the degree of entanglement between the source and the matter of the belief. After seeing the evidence then the probability assessment will on average remain the same; if it was weaker/stronger it will be lower/higher (or higher/lower, if evidence was downward) but it will of course not pass over the initial position before I heard of the news, unless of course it turns out to be evidence for the opposite direction.
Using drugs instead of boxes if that is an example you prefer: imagine a clever arguer hired by Merck to argue about what a great drug Rofecoxib is. The words “cardiovascular”, “stroke”, and “heart attack” wont ever come up. With the help of selectively drawing from trials, a CA can paint a truly wonderful picture of the drug that has limited baring on reality.
Before seeing his evidence he tells you “Rofecoxib is wonderful!” This shouldn’t modify your belief, as it only tells you he is on Merck’s payroll. Now how do you appropriately modify your belief on the drug’s quality and merits with the introduction of each piece of evidence this clever arguer presents to you?
Actually, it’s my bad—I found your comment via the new-comments list, and didn’t look very closely at its context.
As to your actual question: Being told that someone has evidence of something is, if they’re trustworthy, not just evidence of the thing, but also evidence of what other evidence exists. For example, in my scenario with gwern’s prank, before I’ve seen gwern’s web page, I expect that if I look the mentioned drug up in other places, I’ll also see evidence that it’s awesome. If I actually go look the drug up and find out that it’s no better than placebo in any situation, that’s also surprising new information that changes my beliefs—the same change that seeing gwern’s “April Fools” message would cause, in fact, so when I do see that message, it doesn’t surprise me or change my opinion of the drug.
In your scenario, I trust Merck’s spokesperson much less than I trust gwern, so I don’t end up with nearly so strong of a belief that third parties will agree that the drug is a good one—looking it up and finding out that it has dangerous side effects wouldn’t be surprising, so I should take the chance of that into account to begin with, even if the Merck spokesperson doesn’t mention it. This habit of keeping possible information from third parties (or information that could be discovered in other ways besides talking to third parties, but that the person you’re speaking to wouldn’t tell you even if they’d discovered it) into account when talking to untrustworthy people is the intended lesson of the original post.