The disagreement [between Phil and Bob] comes out most clearly when we consider split brain cases. We share the view that the result of a corpus callosotomy is two distinct streams of experiences [...] But he [Bob] holds that each post-surgery person has, say, 0.99x the welfare capacity as the pre-surgery person, so that, say, putting a body with a split brain in an ice bath is 1.98x as bad from a utilitarian perspective as putting a body with an intact brain in the same ice bath.[8] My [Phil’s] guess is that putting the former in the ice bath is, say, 0.99x as bad: the negative welfare inflicted on each person is half as bad due to the simple halving of the experiences, minus perhaps a little bit due to the disappearance of some cognitively sophisticated kinds of discomfort.
Here is a report from Gemini about the following questions I asked. “Do split-brain patients have 2 streams of consciousness? If so, what is the expected hedonistic welfare per unit time of each stream as a fraction of that of the single stream of a normal human?”. I found the report insightful, although I do not trust the quantitative results presented at the end.
Thanks for sharing! I wasn’t aware of the case for thinking that the right hemisphere has so much less welfare capacity than the left. If this is true, it leaves me thinking that the sum of the welfare capacities of the two parts of the split brain patient is significantly less than 1, rather than the 0.99 I went with in the example.
It’s interesting that this EA Forum post forms so much of the basis for its answer to the second question. I wonder if it’s because so little has been written on this, or just because the way you asked the question used language especially similar to this post.
Even though the Gemini report seems to represent my view (what it calls the “divisive model”) and Fischer’s view (the “additive model”) well at first, it gets pretty confused in a few places:
In Section 3.1, it defines hedonistic welfare per unit time in precisely the way I’m arguing against, where there’s no “size” dimension and all it means to be “a being with a higher [welfare] capacity” is that you “can experience ‘deeper’ pain or ‘higher’ pleasure”.
It says that the divisive model is captured by the quote
“The view that expanding a mind from one hemisphere to two… would increase its welfare capacity by much less than 100%—indeed, only by something like 1%.”
It then says it
reject[s] the “Strict Divisive” model because pain does not dilute with volume,
(and also rejects the “Strict Additive” model), and goes with what it frames as something in the middle, but which is fully the additive model after adjusting for the fact that, in its view, the right hemisphere lacks various capacities. -- But, despite the counterintuitive terminology it’s chosen, it’s the Additive view, not the Divisive view, on which “pain dilutes with volume”. The Additive view says that total pain falls if you reconnect the two hemispheres of a split-brain patient in the ice bath, because a welfare subject’s pain is something like an average of pain across the phenomenal field rather than a sum.
Here is a report from Gemini about the following questions I asked. “Do split-brain patients have 2 streams of consciousness? If so, what is the expected hedonistic welfare per unit time of each stream as a fraction of that of the single stream of a normal human?”. I found the report insightful, although I do not trust the quantitative results presented at the end.
Thanks for sharing! I wasn’t aware of the case for thinking that the right hemisphere has so much less welfare capacity than the left. If this is true, it leaves me thinking that the sum of the welfare capacities of the two parts of the split brain patient is significantly less than 1, rather than the 0.99 I went with in the example.
It’s interesting that this EA Forum post forms so much of the basis for its answer to the second question. I wonder if it’s because so little has been written on this, or just because the way you asked the question used language especially similar to this post.
Even though the Gemini report seems to represent my view (what it calls the “divisive model”) and Fischer’s view (the “additive model”) well at first, it gets pretty confused in a few places:
In Section 3.1, it defines hedonistic welfare per unit time in precisely the way I’m arguing against, where there’s no “size” dimension and all it means to be “a being with a higher [welfare] capacity” is that you “can experience ‘deeper’ pain or ‘higher’ pleasure”.
It says that the divisive model is captured by the quote
It then says it
(and also rejects the “Strict Additive” model), and goes with what it frames as something in the middle, but which is fully the additive model after adjusting for the fact that, in its view, the right hemisphere lacks various capacities. -- But, despite the counterintuitive terminology it’s chosen, it’s the Additive view, not the Divisive view, on which “pain dilutes with volume”. The Additive view says that total pain falls if you reconnect the two hemispheres of a split-brain patient in the ice bath, because a welfare subject’s pain is something like an average of pain across the phenomenal field rather than a sum.