I’ve never been a fan of the notion that we should (normatively) have a discount rate in our pure preferences – as opposed to a pseudo-discount rate arising from monetary inflation, or from opportunity costs of other investments… If you wouldn’t burn alive 1,226,786,652 people today to save Giordano Bruno from the stake in 1600, then clearly, you do not have a 5%-per-year temporal discount rate in your pure preferences.
While this is music to the ears of environmentalists everywhere, Robin replies,
Very distant future times are ridiculously easy to help via investment. A 2% annual return adds up to a googol (10^100) return over 12,000 years, even if there is only a 1/1000 chance they will exist or receive it.
So if you are not incredibly eager to invest this way to help them, how can you claim to care the tiniest bit about them? How can you think anyone on Earth so cares? And if no one cares the tiniest bit, how can you say it is “moral” to care about them[?]