Someone may have made this point somewhere else already, but there’s really no mystery in Americans getting fatter if we condition on the trajectory of mean calorie intake.
Read literally, this says: There’s a mystery of why intake went up. Conditioned on intake up, there’s no mystery of why fat went up. I think this isn’t right. If we agreed that sustained high intake implies weight increase, it’s still not right. That’s because conditional probability isn’t the same as explanation, and if there’s a mystery, what we’re after is explanation. That’s one of the points of the tumor example: If fat causes intake, then saying “there’s no mystery about fat” is pointing away from the explanation of intake, which is that fat causes intake and something causes fat.
They later tried to address this because people picked up on it and eventually said “well, even if the 20% increase explains the obesity epidemic, that still leaves the question of why people are eating more open”. I think this is bizarre: to me it’s quite obvious that in the long run more calorie intake has to lead to higher body mass, though not necessarily in a proportional way as I’ve idealized above. They should have been focusing on the causal channel going through calorie intake from the start. Instead, it seems like to them this was a secondary channel to fall back on.
Taken literally, this seems to be consistent with beliefs of people who disagree with you? It’s just that they have different conclusions about the causality going through calorie intake. Interpreted that way, I don’t see how this statement is consistent with saying “there’s really no mystery in Americans getting fatter”.
I don’t understand your objection. I never made any claims about causality. My whole argument is about energy balance, which says nothing about causality.
On the other hand, I think it’s just true that conditioned on the increase in calorie intake there’s no mystery in the increase in body mass. I don’t understand why you’re disputing this point. You can say this is not an interesting observation (which I agree with, though as far as I can tell SMTM did not, which is why I wrote my comment) but I don’t see how you can say it’s not right.
My impression is that some people are engaging in a bizarre combination of steelmanning SMTM’s point while strawmanning my own. SMTM didn’t make the best version of the claim they could have made, they made the actual claim that I quote in my post. I think their claim is wrong. Do you disagree with this or not?
Meta: my interest here is to see if there are miscommunications here that I can clear up. I’m not carefully following the object-level debate. (In particular, I think that you Ege should feel extremely free to ignore what I’m saying as unhelpful to you; if I’m not helping you understand what’s happening in the thread then I’m not doing what I’m trying to do.)
I don’t understand your objection. I never made any claims about causality. My whole argument is about energy balance, which says nothing about causality.
On the other hand, I think it’s just true that conditioned on the increase in calorie intake there’s no mystery in the increase in body mass. I don’t understand why you’re disputing this point.
(Note: you did mention causality in the passage I quoted: “They should have been focusing on the causal channel going through calorie intake from the start.” That’s not a claim about what causes what, but it is a claim about what questions are the right questions to ask.)
I’m pointing at the word “mystery”. I’m saying that to me, “mystery” means “explanation wanted”. I’m saying that just because P(X|Y) is high, doesn’t mean Y is a good explanation of X. (For a silly example, setting Y=”X and 2+1=3″ makes P(X|Y) = 1 and is obviously doesn’t explain anything.) I agree (based on my preconceptions, ~0 independent data) that P(body mass high | high sustained intake in the wild) is high. My read of some of the comments on your comment, e.g. Yudkowsky’s, is that they are taking you to be saying “high intake explains fat, such that there is no further interesting question about fat, though there may be further questions about why high intake”, based on the passages from your comment I quoted. Reading your comment closely, you didn’t actually say that, if by “conditional on Y, there’s no mystery about X” you mean “P(X|Y) is high”. In fact, what you said is consistent with believing that “Alice is fat” explains (in the contextually relevant sense) that “Alice has high intake”, and you recommend that if you believe this then you should “focus[] on the causal channel going through calorie intake”, i.e. investigate why Alice is fat in order to explain her high intake.
SMTM didn’t make the best version of the claim they could have made, they made the actual claim that I quote in my post. I think their claim is wrong. Do you disagree with this or not?
I don’t know. I think your argument makes sense, but the actual situation is going to be more complicated.
In your original comment, you wrote:
Read literally, this says: There’s a mystery of why intake went up. Conditioned on intake up, there’s no mystery of why fat went up. I think this isn’t right. If we agreed that sustained high intake implies weight increase, it’s still not right. That’s because conditional probability isn’t the same as explanation, and if there’s a mystery, what we’re after is explanation. That’s one of the points of the tumor example: If fat causes intake, then saying “there’s no mystery about fat” is pointing away from the explanation of intake, which is that fat causes intake and something causes fat.
Taken literally, this seems to be consistent with beliefs of people who disagree with you? It’s just that they have different conclusions about the causality going through calorie intake. Interpreted that way, I don’t see how this statement is consistent with saying “there’s really no mystery in Americans getting fatter”.
I don’t understand your objection. I never made any claims about causality. My whole argument is about energy balance, which says nothing about causality.
On the other hand, I think it’s just true that conditioned on the increase in calorie intake there’s no mystery in the increase in body mass. I don’t understand why you’re disputing this point. You can say this is not an interesting observation (which I agree with, though as far as I can tell SMTM did not, which is why I wrote my comment) but I don’t see how you can say it’s not right.
My impression is that some people are engaging in a bizarre combination of steelmanning SMTM’s point while strawmanning my own. SMTM didn’t make the best version of the claim they could have made, they made the actual claim that I quote in my post. I think their claim is wrong. Do you disagree with this or not?
Meta: my interest here is to see if there are miscommunications here that I can clear up. I’m not carefully following the object-level debate. (In particular, I think that you Ege should feel extremely free to ignore what I’m saying as unhelpful to you; if I’m not helping you understand what’s happening in the thread then I’m not doing what I’m trying to do.)
(Note: you did mention causality in the passage I quoted: “They should have been focusing on the causal channel going through calorie intake from the start.” That’s not a claim about what causes what, but it is a claim about what questions are the right questions to ask.)
I’m pointing at the word “mystery”. I’m saying that to me, “mystery” means “explanation wanted”. I’m saying that just because P(X|Y) is high, doesn’t mean Y is a good explanation of X. (For a silly example, setting Y=”X and 2+1=3″ makes P(X|Y) = 1 and is obviously doesn’t explain anything.) I agree (based on my preconceptions, ~0 independent data) that P(body mass high | high sustained intake in the wild) is high. My read of some of the comments on your comment, e.g. Yudkowsky’s, is that they are taking you to be saying “high intake explains fat, such that there is no further interesting question about fat, though there may be further questions about why high intake”, based on the passages from your comment I quoted. Reading your comment closely, you didn’t actually say that, if by “conditional on Y, there’s no mystery about X” you mean “P(X|Y) is high”. In fact, what you said is consistent with believing that “Alice is fat” explains (in the contextually relevant sense) that “Alice has high intake”, and you recommend that if you believe this then you should “focus[] on the causal channel going through calorie intake”, i.e. investigate why Alice is fat in order to explain her high intake.
I don’t know. I think your argument makes sense, but the actual situation is going to be more complicated.