Open Thread, November 15-22, 2013

drethelin

If it's worth saying, but not worth its own post (even in Discussion), then it goes here.

I've been thinking about scope insensitivity, and wonder whether it can be mistaken for decreasing marginal value. Suppose a slice of pizza costs $1, and you're willing to buy it for that much. That doesn't mean that you'd be willing to buy a million slices of pizza for a million dollars - in fact, if you're only hungry enough for one slice and don't have a refrigerator handy, you may not want to pay more than $1 for any amount of pizza greater than or equal to once slice. The same can apply to donating to charity to save lives. You may value saving one life for $200, but maybe you're not willing to pay $400 to save two lives.

That does raise the question of why you only value lives you saved. If all lives are important, marginal value won't change much over one life saved.

4A1987dM12y

Eliezer's answer (I can't find it at the moment) is that there are many more lives around, and it seems unlikely that U(875,431 people die) - U(875,430 people die) is that different from U(875,430 people die) - U(875,429 people die). (OTOH, once you've spent $200 to save a life, you have $200 less, and so the marginal utility of another $200 is larger.)

10AlexSchell12y

This is what scope insensitivity is. The original paper calls it "purchase of moral satisfaction" -- the revealed preference in these experiments is for an internal state of moral satisfaction as opposed to the actual lives you're saving. Like hunger, the internal state is quickly satiated and so exhibits diminishing returns, but actual lives do not exhibit diminishing returns (in the relevant range, for humans, on reflection).