We don’t. The argument in the post is trying to solve the problem of protecting whatever current values you happen to have (and the values that your past selves happened to have, if you care about them), not the problem of finding absolute eternal values (whatever that means).
My understanding of “eternal values” is precisely the thing I get if I solve the problem of protecting my current values in a sufficiently general way: a set of values that does not change over time. This is in the same sense that solving the “don’t die today” problem in a sufficiently general way provides eternal life.
Can anyone explain why, in a rapidly changing world, we need “absolute” and “eternal” morality?
We don’t. The argument in the post is trying to solve the problem of protecting whatever current values you happen to have (and the values that your past selves happened to have, if you care about them), not the problem of finding absolute eternal values (whatever that means).
My understanding of “eternal values” is precisely the thing I get if I solve the problem of protecting my current values in a sufficiently general way: a set of values that does not change over time. This is in the same sense that solving the “don’t die today” problem in a sufficiently general way provides eternal life.