Future people count. There could be a lot of them. We can make their lives go better.

This is the case for longtermism in a nutshell. The premises are simple, and I don’t think they’re particularly controversial. Yet taking them seriously amounts to a moral revolution—one with far-reaching implications for how activists, researchers, policy makers, and indeed all of us should think and act.

It’s not just technology that has improved people’s lives; moral change has done so, too. In 1700, women were unable to attend university, and the feminist movement did not exist.If that well-off Brit was gay, he could not love openly; sodomy was punishable by death. In the late 1700s, three in four people globally were the victims of some form of forced labour; now less than 1 percent are. In 1700, no one lived in a democracy. Now over half the world does.

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.

For this reason, even if you think that the absence of future generations is not a moral loss or that the end of civilisation would be a good thing (issues that I discuss in Part IV), it’s still very important to avoid AI takeover or the lock-in of bad values. There will be future generations of intelligent beings either way, and by preventing the takeover of the world by an AI with bad values, you are changing how good or bad the future is over the course of civilisation’s life span. That’s the main effect, rather than any impacts on civilisation’s life expectancy.