What We Owe the Future Summary and key ideas

What We Owe the Future, by William MacAskill.

Imagine living every human life in sequence, from humanity’s beginnings through the people alive now, and then continuing through future lives. This is not a claim about reincarnation. It is a way to widen the point of view. The sequence would consist mostly of ordinary days: working, raising children, worshipping, making friends, suffering illness, and enjoying pleasure. It would also mean occupying opposing positions in systems of power and violence, as enslaver and enslaved, colonizer and colonized, abuser and abused. History becomes less like a story watched from outside and more like one enormous life shared among people.

The thought experiment asks us to take each person’s experience seriously, whoever they are and whenever they live. Future people do not yet exist from our perspective, but when they do, their hopes, joys, pain, and regret will be real to them. Their interests do not become trivial just because they come later. MacAskill’s first point is simple: the passage of time alone does not erase moral importance.

Consider a hiker who leaves broken glass on a trail. Someone may be injured much later, but the delay would not make the danger harmless. Or imagine knowing that a plague will threaten people in the future. If we could help prevent it, its later arrival would not make those people’s suffering count for less. Benefits work the same way: a future person’s enjoyment of a concert or sporting event is not worth less solely because it happens later. These examples make temporal distance feel like what it is: distance in time, not proof that the people affected matter less.

The book also asks us to imagine an unseen civilization beneath the ocean, sometimes called Atlantis. People there might be harmed by human actions such as dumping waste; when a ship sinks, they recycle it for scrap metal and parts. The point is not that such a civilization exists. The thought experiment separates moral concern from familiarity, visibility, and reciprocal relationships. If we can recognize the interests of people we cannot meet, future generations need not be excluded simply because they are harder to picture.

That does not mean every decision must give everyone equal weight. Close relationships and obligations to people who have helped us can justify special responsibilities to family, friends, and others alive today. The argument for future concern adds to ordinary moral concern; it does not cancel those relationships or make present suffering unimportant. MacAskill acknowledges that immediate problems can feel more urgent than the needs of people who are still abstract to us. His claim is that abstraction and distance are not, by themselves, reasons to ignore them.

A second question is how many future people there could be. The past and present can feel like the whole human story because they are the parts we know. Yet humanity could survive much longer than it has existed so far, and the population of future generations might be large. In one illustrative scenario, if humanity lasted about as long as a typical mammal species while maintaining today’s population, roughly eighty trillion people could be born. That is a scenario, not a forecast: humanity could instead face a much shorter future, and population levels could change. The estimate matters as a demonstration of possible scale, not as a prediction that its assumptions will come true.

The third question concerns the quality of those possible lives. The future might hold lives far better than the best lives available today, with forms of health, knowledge, freedom, and flourishing we cannot yet imagine. MacAskill suggests that even a future where everyone enjoyed today’s best living standards might understate what is possible. But a good future is not guaranteed. Human choices could also produce oppression, suffering, or the destruction of humanity’s prospects. These are contrasting possibilities, not claims that either outcome is certain. The range of what could happen is part of why the stakes deserve attention.

The fourth question is whether people alive now can affect those conditions. The answer need not be that any one person controls the distant future. Present actions can influence what future generations inherit through institutions, ideas, technology, investments, and environmental conditions. Some effects are deliberate; others travel through long chains of decisions and transmission. That influence may be substantial, but it is uncertain, and the existence of influence does not mean we can know exactly where it leads.

Together, the four ideas form a basic test for why the future matters: future people count morally; there could be very many of them; their lives could be exceptionally good or bad; and our choices can affect the conditions they face. The argument does not require certainty about population, lifespan, or outcomes. It asks us to treat those possibilities as morally relevant rather than dismissing them because they lie beyond the present. The future is not separate from ordinary concern for people. It extends that concern to people we cannot yet see.