We don’t need to predict every detail, nor could we if we tried. But if we want to make the future better, we need to identify actions that have positive effects on balance over very long timescales.

For these reasons changing values has particularly great significance from a longterm perspective. Looking to the past, we see that such changes have had an enormous impact on the lives of billions of people. Looking to the future, if we can improve the values that guide the behaviour of generations to come, we can be pretty confident that they will take better actions, even if they’re living in a world very different from our own, the nature of which we cannot predict.

This suggests that, as longtermists, when trying to improve society’s values, we should focus on promoting more abstract or general moral principles or, when promoting particular moral actions, tie them into a more general worldview. This helps ensure that these moral changes stay relevant and robustly positive into the future.

When confronted with the empirical and evaluative complexity that faces us, it can be easy to feel clueless, as if there’s nothing at all we can do. But that would be too pessimistic. Even if we’re walking backwards into the future—and even if the terrain we’re walking on is unexplored, it’s dark and foggy, and we have few clues to guide us—nonetheless, some plans are smarter than others. We can employ three rules of thumb.

People such as James West and Jennifer Heemstra and Clarence Dennis skillfully applied the lessons they gleaned from painful setbacks as part of building successful and fulfilling lives. But we’re not hardwired to confront failure thoughtfully; we have to learn to do it.