Narrator: What if the past was in front of you, and the future was behind you? For the Aymara people of the Andes, this isn't a riddle; it's how they perceive time. The past is "in front" because it has been seen and is known. The future is "behind" because it is unseen and unknown. We can only walk backwards into it, guided by the knowledge of what has come before. This perspective-shifting concept challenges our most basic assumptions about our place in history and our relationship with what is yet to come.

This very challenge is at the heart of philosopher William MacAskill's profound work, What We Owe the Future. The book presents a powerful and meticulously argued case for "longtermism"—the idea that our most pressing moral obligation is to ensure that future generations can flourish. It asks us to look beyond the immediate crises of our time and consider the immense, unwritten story of humanity, a story whose quality and length depend entirely on the choices we make today.

Narrator: At its core, longtermism rests on a simple, intuitive idea: future people count. Their distance from us in time is no more morally relevant than distance in space. MacAskill illustrates this with a simple thought experiment. Imagine you are hiking in a remote forest and accidentally drop a glass bottle, which shatters on the path. You know that if you leave the shards, a child might cut their foot badly. Does it matter if that child will come along in a week, a decade, or a century? The harm is the same. The suffering is just as real. Most would agree that the right thing to do is to clean up the glass.

MacAskill argues that our current actions are like shattering glass on a path that trillions of people may one day walk. The future of humanity could be extraordinarily long and unimaginably vast. If humanity survives for even a fraction of its potential lifespan, we who are alive today are the ancients, living at the very dawn of history. The sheer scale of potential future lives—in the trillions upon trillions—means that even small improvements to the long-term trajectory of civilization, or small reductions in the risk of its extinction, can have an astronomical moral value. This isn't just about making people happy; it's about the goodness of creating happy people in the first place.

Narrator: A common objection to longtermism is that the future is too unpredictable to influence. MacAskill counters this by providing a framework for thinking about long-term impact, based on three factors: significance, persistence, and contingency. An action is significant if it brings about a great deal of good or bad. It is persistent if its effects last for a long time. And it is contingent if the action is what makes the difference—if the outcome wouldn't have happened otherwise.

A stark example of contingency can be found in the division of Korea. After World War II, two American colonels, with no expertise on Korea, were given thirty minutes to propose a dividing line. Using a National Geographic map, they chose the thirty-eighth parallel. The Soviets accepted, and this hasty, almost random decision became a fixed reality. The line hardened into a border that has determined the fate of millions, creating a prosperous, democratic South and a desperately poor, totalitarian North. This single, contingent decision, made in a moment of historical plasticity, has had devastatingly significant and persistent consequences, demonstrating that our choices can, and do, shape the course of history in profound ways.

Narrator: Many assume that moral progress is an unstoppable force. MacAskill challenges this, arguing that our values are just as contingent as other historical events. He points to the abolition of slavery, which was far from inevitable. For millennia, slavery was a near-universal institution. Its abolition was driven by a small group of determined moral activists, like the radical Quaker Benjamin Lay. In the 1730s, Lay performed shocking acts of public protest, once splattering fellow Quakers with red juice hidden in a hollowed-out book to symbolize the blood on their hands from the slave trade. His radical, tireless campaigning helped shift the values of a society, sparking a movement that eventually changed the world.

This contingency of values presents a monumental risk for the future: value lock-in. With the rise of powerful technologies like artificial general intelligence (AGI), it's possible that a single set of values—whether good or bad—could become permanently entrenched on a global, or even cosmic, scale. An AGI designed with flawed or even malevolent goals could perpetuate those goals for millions of years, preventing any further moral progress. This creates an urgent need not just to survive, but to build a "morally exploratory" world, one that preserves the ability for future generations to discover better ways of living.

Narrator: To secure a flourishing future, humanity must navigate three great risks. The first is extinction. While asteroid impacts are a known threat, MacAskill argues the greater danger now comes from ourselves, particularly through engineered pathogens. With modern biotechnology, creating a virus more transmissible and deadlier than any natural disease is becoming terrifyingly plausible. A single leak from a poorly secured lab could trigger a pandemic that ends civilization.

The second risk is unrecoverable collapse. History is filled with fallen civilizations, like the Roman Empire. But a future collapse could be permanent. The Industrial Revolution was powered by easily accessible fossil fuels. If our civilization falls after we have depleted these resources, a future society might find it impossible to re-industrialize, trapping them in a pre-industrial state forever.

The third, more subtle risk is stagnation. This is a scenario where technological and economic progress grinds to a halt for centuries or millennia. We might be in a great "efflorescence" of growth, similar to the Islamic Golden Age or Ancient Greece, that is destined to end. A long stagnation would leave us vulnerable, stuck with dangerous technologies but without the means to solve the problems they create, increasing the odds of an eventual collapse or extinction.

Narrator: A crucial philosophical question underpins the entire longtermist project: is it actually a good thing to create more people? Many hold the "intuition of neutrality"—that while it's bad to create an unhappy person, it's morally neutral to create a happy one. MacAskill argues this view is flawed. He presents a scenario: a couple can have a child now who will suffer from lifelong migraines, or they can wait a month and have a perfectly healthy child. Clearly, it's better to have the healthy child. But if creating a happy person is neutral, then having the healthy child is no better than having no child at all. This leads to a logical contradiction.

Rejecting this neutrality means accepting that bringing a flourishing life into the world is a positive good. This has staggering implications. It means that an extinction event is not just a tragedy for the people who die, but a cosmic tragedy for the countless happy lives that will never be. It transforms the future from a blank slate into a potential repository of immense value, a value we have the power to protect and realize. This makes ensuring humanity's survival and expansion into the cosmos a project of the highest moral importance.

Narrator: The single most important takeaway from What We Owe the Future is that we are living in the most pivotal era of human history. The decisions made in our lifetimes—regarding artificial intelligence, biosecurity, and the stability of our civilization—will echo for millennia. We hold the fate of an almost infinite number of future people in our hands, yet we barely give them a thought.

MacAskill's work is not a prophecy of doom, but a call to action grounded in reasoned optimism. It challenges us to expand our moral circle across time and to recognize our profound power. The ultimate question it leaves us with is not just what we owe the future, but what we will do with this awesome responsibility. As the ancient Jewish sage Hillel the Elder asked, in a question that resonates powerfully through this book: "If not you, who? And if not now, when?"