What We Owe the Future
Our duty to the unborn
Description
In 2022, a Scottish philosopher barely past forty published a book arguing that the most important people in the world are people who do not yet exist. William MacAskill was already a known figure — a founder of effective altruism, the movement that tells donors to follow the evidence and the numbers rather than their feelings. But "What We Owe the Future" pushed his argument somewhere stranger. The claim was simple to state and hard to absorb: future generations matter morally, there are potentially a staggering number of them, and almost nobody is acting as if either of those things were true.
The scale he asks us to hold in mind is genuinely odd. If humanity survives as long as a typical mammal species, the people alive today are a rounding error against everyone who comes after. Picture the whole of the human future as a single life, and we are living through its earliest infancy — except this infant gets to make decisions that bind the adult it will become. We pour carbon into an atmosphere our grandchildren's grandchildren will breathe. We build technologies whose settings could outlast every institution now standing. And we do it, mostly, while thinking about the next quarter or the next election.
MacAskill's wager is that this is a mistake we can correct — that long-term thinking is not a vague virtue but a discipline, one you can actually build into how you weigh a decision. That is the move worth following. Not the headline that the future matters, which most of us would nod along to, but the harder question of what changes once we take it seriously.
The question we’re asking : If the future contains far more people than the present, what do we actually owe them — and how would we even begin to act on it?What we’ll see : How MacAskill turns a sweeping moral intuition into a working framework, and where that framework strains.
Table of contents
01Chapter 1 — The future is a place we keep flooding
MacAskill likes to start with a thought that sounds almost banal until you sit with it. When we toss a glass bottle into a forest, we have some sense that a child decades from now could cut their foot on it. We accept that the harm is real even though the victim is unnamed and unborn. The intuition is already there. What he wants to do is take that small, intact moral reflex and scale it up to the size of civilization.
Climate is his cleanest example, and he treats it carefully rather than as a slogan. Carbon dioxide does not flush out of the atmosphere on any human timescale; a meaningful fraction of what we emit now will still be warming the planet thousands of years from now. So a decision made in a boardroom this decade reaches forward across a span longer than recorded history. The people who inherit it had no vote, no voice, no way to object. They simply receive the bill.
02Chapter 2 — Why the people who don't exist yet still count
The whole argument rests on a claim that trips a lot of readers: that we can have obligations to people who do not yet exist, and may never exist depending on what we do. MacAskill calls his position longtermism, and its core is the idea that positively influencing the long-term future is a key moral priority of our time. Not the only one — but one we have badly neglected.
The objection arrives fast. How can I wrong someone who isn't real? His answer leans on a distinction that does a lot of work. We may not have duties to specific future individuals, the way we owe a promise to a named friend. But we can have duties regarding the future — to make sure that whoever does come after inherits a world worth living in. If you bury toxic waste in a drum set to corrode in two hundred years, it makes no difference to your guilt whether you can name the person it poisons. The wrong is in the burying.
03Chapter 3 — The pivotal century and the values that get locked in
If the future is so vast, why should this particular generation feel any special burden? MacAskill's answer is one of the book's more arresting moves: he thinks we may be living through an unusually pivotal stretch of history, a window in which choices harden into shapes that last. He borrows a phrase for it — value lock-in — and uses it to explain why now might matter more than most moments.
His worry is that values, once embedded in powerful enough systems, can become very hard to dislodge. He points to the long, ugly persistence of slavery as a case where a moral arrangement entrenched itself for millennia and was abolished only through enormous and contingent effort — it did not have to end when it did. Now imagine a value, good or bad, fixed not in fragile human institutions but in technologies designed to be stable and self-perpetuating. Artificial intelligence is his central example: a system powerful enough to enforce a particular set of aims could, in principle, hold them in place far longer than any empire ever managed.
04Chapter 4 — A philosophy that puts numbers where the future used to be
Step back from the specific arguments and "What We Owe the Future" reveals what it really is: an attempt to make moral concern for the future tractable — something you can reason about, estimate, and act on, rather than merely feel. This is the deeper signature of effective altruism, the movement MacAskill helped build, and the book is its most ambitious extension. The project has always been to take the warm, shapeless impulse to do good and give it the tools of evidence and expected value.
The framework he offers has a usable shape. When weighing where to direct effort, he suggests looking at significance — how much a state of affairs matters — alongside persistence — how long it will last — and contingency — whether your action actually changes the outcome, or whether someone would do it anyway. A cause that scores high on all three is where leverage lives. It is a way of asking, coldly and on purpose, which of our many good intentions would do the most enduring good.
05Conclusion
The image MacAskill returns to is the one he opened with: we are an infant civilization with adult powers, making choices whose consequences we will never witness. "What We Owe the Future" does not pretend to settle what those choices should be. It argues something narrower and more demanding — that the future deserves a seat at the table where we make them, and that we have been holding the table for ourselves. Carbon, technology, the values we bake into our most durable systems: each is a decision we are already making on behalf of people who cannot answer back.
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