If you want to talk about "ancestral environment," then note that infanticide is quite common in many cultures, as far as I can tell including hunter-gatherers.

Likelihood to survive seems like a good explanation.

25% of pregnancies end in miscarriage. Miscarriage is common and (at least in the culture I'm familiar with) causes grief, but nowhere near the same kind of grief as losing a born child. The hospital procedure is routine and not attended with the same kind of reverence as death usually is. I think it's because miscarriage is so common that it's not generally considered to have the same gravity as death. I don't even know if there's research being done to reduce miscarriage. (If 25% of humans died of a given disease, you can bet we'd be researching it.)

I think that in point of social fact fetuses aren't granted the same status as babies, even among pro-life people.

this link is messed up in the post

http://lesswrong.com/lw/1ws/the_importance_of_goodharts_law/

"Jam now" is a necessary condition, not a sufficient one.

first hour or day

If I decide to, say, learn Spanish, then I expect every hour spent on the task, including the first one, to pay a perceptible return.

Interestingly 0 as in "free stuff" is also often mispriced (hence all the 'free offers' you get in the mail).

Eliezer writes in the theory of fun that to sell an idea to someone, you usually don't need to convince them it's a good thing to live with for their whole life. You only need to convince them that the first hour or day after they choose is going to be good.

I think that's a rational response, by the person you're trying to convince. The more distant the promised reward of whatever someone is touting to me, the more it will cost to reach it, and the more convinced I would have to be before taking it seriously enough to even begin. Or to put that the other way round, show me something that I can do right now and experience evidence that it works, and the bar for you to sell it to me is much lower.

"Jam tomorrow" is the promise of crooks and charlatans.

The descriptive math part was very good, thanks - and that's why I resisted downvoting the post. My problem is that the conclusion omits the hugely important factor that categories are useful for specific goals, and the kind of techniques you are suggesting (essentially unsupervised techniques) are context-free.

E.g. is a dead cow more similar to a dead (fixed from 'live') horse or to a live cow? (It clearly depends what you want to do with it)

If you can't tell whose side someone is on, they are not on yours. -Warren E. Buffett

The Red guy is a dead ringer for Prime Intellect.