In our everyday ethics, an accident that kills 2 people is about twice as bad as an accident that kills 1 person. So we can use linear assumptions for evaluatin

In our everyday ethics, an accident that kills 2 people is about twice as bad as an accident that kills 1 person. So we can use linear assumptions for evaluating safety measures like seatbelts and vaccines. In the study of existential risk, killing all the people is much, much worse than killing half the people. Because if you integrate over all the people that will ever live, our descendants potentially spreading around the galaxy, killing all of them zeros out all future happiness. Killing half will only reduce population for a century or two.