- Are there any developed versions of long termism that are based off deontology, contractarianism and virtue ethics.
- If so, how do they looked different. It seems very significant if all major schools of normative ethical theories converge
Another emerging debate is whether contractualism can deliver plausible verdicts in cases involving risks of human extinction. The prima facie problem for contractualism here is that, because the outcome where we fail to avoid imminent extinction contains no future people at all, there is no (particular or representative) future person who has the standing to reasonably reject principles instructing present people to ignore extinction risks and focus entirely on meeting present needs. (Finneron-Burns 2017, Frick 2017.)
I'm not sure it follows that a contractualist should focus on present needs, though, since I think some contractualists would accept the procreation asymmetry, and so preventing futures with very bad lives could be important.
Rawls was a contractualist and argued for saving for future generations (assuming they will exist) based on the veil of ignorance; see 4.5 Rawls’s Just Savings Principle in the SEP article Intergenerational Justice:
Thus the correct principle is that which the members of any generation (and so all generations) would adopt as the one their generation is to follow and as the principle they would want preceding generations to have followed (and later generations to follow), no matter how far back (or forward) in time. (Rawls 1993: 274; Rawls 2001: 160)
Still, this seems to me to be a basically consequentialist argument, since, from my understanding, Rawls' treatment of the original position behind veil of ignorance is basically consequentialist.
The article also discusses rights-based approaches and other reasons to care for future generations.
Apparently contractualists are basically Kantian deontologists, though. On the other hand, contractarianism attempts to motivate ethical behaviour through rational self-interest without assuming concern for acting morally or taking the interests of others into account. See the SEP article on contractarianism, which contrasts the two in its introduction and in a few other places in the article.
I've haven't read it, but the name of this paper from Andreas at GPI at least fits what you're asking - "Staking our future: deontic long-termism and the non-identity problem"