I think I might be spoilered from reading the original paper, but my guess is “The impact to someone of an event is how much it changes their ability to get what we want”. Humans care about Iniron existing because it makes it harder to reduce suffering and increase happiness. (Not sure how to square this definition of impact with finding out new info that was already there, as in the case of Iniron, it had already existed, we just found out about it.) Pebblites care about all their pebbles becoming obsidian because it changes their ability to stack pebbles. Both humans and pebblites care about being hit by an asteroid because it’s harder to pursue one’s values if one is killed by an asteroid.
Translation to normal spoiler text:
I think I might be spoilered from reading the original paper, but my guess is “The impact to someone of an event is how much it changes their ability to get what we want”. Humans care about Iniron existing because it makes it harder to reduce suffering and increase happiness. (Not sure how to square this definition of impact with finding out new info that was already there, as in the case of Iniron, it had already existed, we just found out about it.) Pebblites care about all their pebbles becoming obsidian because it changes their ability to stack pebbles. Both humans and pebblites care about being hit by an asteroid because it’s harder to pursue one’s values if one is killed by an asteroid.