What We Owe the Future

Imagine living, in order of birth, through the life of every human being who has ever lived.1 Your first life begins about three hundred thousand years ago in Africa.2 After living that life and dying, you travel back in time and are reincarnated as the second-ever person, born slightly later than the first. Once that second person dies, you are reincarnated as the third person, then the fourth, and so on. One hundred billion lives later,3 you become the youngest person alive today. Your “life” consists of all of these lifetimes, lived consecutively.

Your experience of history is very different from what is depicted in most textbooks. Famous figures like Cleopatra or Napoleon account for a tiny fraction of your experience. The substance of your life is instead composed of ordinary lives, filled with everyday realities—eating, working, and socialising; laughing, worrying, and praying.

Your life lasts for almost four trillion years in total. For a tenth of that time, you’re a hunter-gatherer, and for 60 percent you’re an agriculturalist.4 You spend a full 20 percent of your life raising children, a further 20 percent farming, and almost 2 percent taking part in religious rituals. For over 1 percent of your life you are afflicted with malaria or smallpox. You spend 1.5 billion years having sex and 250 million giving birth. You drink forty-four trillion cups of coffee.5

You experience cruelty and kindness from both sides. As a colonizer, you invade new lands; as the colonized, you suffer your lands taken from you. You feel the rage of the abuser and the pain of the abused. For about 10 percent of your life you are a slaveholder; for about the same length of time, you are enslaved.6

You experience, firsthand, just how unusual the modern era is. Because of dramatic population growth, a full third of your life comes after AD 1200 and a quarter after 1750. At that point, technology and society begin to change far faster than ever before. You invent steam engines, factories, and electricity. You live through revolutions in science, the most deadly wars in history,7 and dramatic environmental destruction. Each life lasts longer, and you enjoy luxuries that you could not sample even in your past lives as kings and queens. You spend 150 years in space and one week walking on the moon. Fifteen percent of your experience is of people alive today.8

That’s your life so far—from the birth of Homo sapiens until the present. But now imagine that you live all future lives, too. Your life, we hope, would be just beginning. Even if humanity lasts only as long as the typical mammalian species (one million years), and even if the world population falls to a tenth of its current size, 99.5 percent of your life would still be ahead of you.9 On the scale of a typical human life, you in the present would be just five months old. And if humanity survived longer than a typical mammalian species—for the hundreds of millions of years remaining until the earth is no longer habitable, or the tens of trillions remaining until the last stars burn out—your four trillion years of life would be like the first blinking seconds out of the womb.10 The future is big.

If you knew you were going to live all these future lives, what would you hope we do in the present? How much carbon dioxide would you want us to emit into the atmosphere? How much would you want us to invest in research and education? How careful would you want us to be with new technologies that could destroy or permanently derail your future? How much attention would you want us to give to the impact of today’s actions on the long term?

I present this thought experiment because morality, in central part, is about putting ourselves in others’ shoes and treating their interests as we do our own. When we do this at the full scale of human history, the future—where almost everyone lives and where almost all potential for joy and misery lies—comes to the fore.

This book is about longtermism: the idea that positively influencing the longterm future is a key moral priority of our time.11 Longtermism is about taking seriously just how big the future could be and how high the stakes are in shaping it. If humanity survives to even a fraction of its potential life span, then, strange as it may seem, we are the ancients: we live at the very beginning of history, in the most distant past. What we do now will affect untold numbers of future people. We need to act wisely.

It took me a long time to come around to longtermism. It’s hard for an abstract ideal, focused on generations of people whom we will never meet, to motivate us as more salient problems do. In high school, I worked for organisations that took care of the elderly and disabled. As an undergraduate who was concerned about global poverty, I volunteered at a children’s polio rehabilitation centre in Ethiopia. When starting graduate work, I tried to figure out how people could help one another more effectively. I committed to donating at least 10 percent of my income to charity, and I cofounded an organization, Giving What We Can, to encourage others to do the same.12

These activities had a tangible impact. By contrast, the thought of trying to improve the lives of unknown future people initially left me cold. When a colleague presented me with arguments for taking the long term seriously, my immediate reaction was glib dismissal. There are real problems in the world facing real people, I thought, problems like extreme poverty, lack of education, and death from easily preventable diseases. That’s where we should focus. Sci-fi-seeming speculations about what might or might not impact the future seemed like a distraction.

But the arguments for longtermism exerted a persistent force on my mind. These arguments were based on simple ideas: that, impartially considered, future people should count for no less, morally, than the present generation; that there may be a huge number of future people; that life, for them, could be extraordinarily good or inordinately bad; and that we really can make a difference to the world they inhabit.

The most important sticking point for me was practical: Even if we should care about the longterm future, what can we do? But as I learned more about the potentially history-shaping events that could occur in the near future, I took more seriously the idea that we might soon be approaching a critical juncture in the human story. Technological development is creating new threats and opportunities for humanity, putting the lives of future generations on the line.

I now believe the world’s long-run fate depends in part on the choices we make in our lifetimes. The future could be wonderful: we could create a flourishing and long-lasting society, where everyone’s lives are better than the very best lives today. Or the future could be terrible, falling to authoritarians who use surveillance and AI to lock in their ideology for all time, or even to AI systems that seek to gain power rather than promote a thriving society. Or there could be no future at all: we could kill ourselves off with biological weapons or wage an all-out nuclear war that causes civilisation to collapse and never recover.

There are things we can do to steer the future onto a better course. We can increase the chance of a wonderful future by improving the values that guide society and by carefully navigating the development of AI. We can ensure we get a future at all by preventing the creation or use of new weapons of mass destruction and by maintaining peace between the world’s great powers. These are challenging issues, but what we do about them makes a real difference.

So I shifted my priorities. Still unsure about the foundations and implications of longtermism, I switched my research focus and cofounded two organisations to investigate these issues further: the Global Priorities Institute at Oxford University, and the Forethought Foundation. Drawing on what I have learned, I have tried to write the case for longtermism that would have convinced me a decade ago.

To illustrate the claims in this book, I rely on three primary metaphors throughout. The first is of humanity as an imprudent teenager. Most of a teenager’s life is still ahead of them, and their decisions can have lifelong impacts. In choosing how much to study, what career to pursue, or which risks are too risky, they should think not just about short-term thrills but also about the whole course of the life ahead of them.

The second is of history as molten glass. At present, society is still malleable and can be blown into many shapes. But at some point, the glass might cool, set, and become much harder to change. The resulting shape could be beautiful or deformed, or the glass could shatter altogether, depending on what happens while the glass is still hot.

The third metaphor is of the path towards longterm impact as a risky expedition into uncharted terrain. In trying to make the future better, we don’t know exactly what threats we will face or even exactly where we are trying to go; but, nonetheless, we can prepare ourselves. We can scout out the landscape ahead of us, ensure the expedition is well resourced and well coordinated, and, despite uncertainty, guard against those threats we are aware of.

This book’s scope is broad. Not only am I arguing for longtermism; I’m also trying to work out its implications. I’ve therefore relied heavily on an extensive team of consultants and research assistants. Whenever I’ve stepped outside of moral philosophy, my area of expertise, domain experts have advised me from start to end. This book is therefore not really “mine”: it has been a team effort. In total, this book represents over a decade’s worth of full-time work, almost two years of which was spent fact-checking.

For those who want to dig deeper into some of my claims, I have compiled extensive supplementary materials, including special reports I commissioned as background research, and made them available at whatweowethefuture.com. Despite the work done so far, I believe we have only scratched the surface of longtermism and its implications; there is much still to learn.

If I’m right, then we face a huge responsibility. Relative to everyone who could come after us, we are a tiny minority. Yet we hold the entire future in our hands. Everyday ethics rarely grapples with such a scale. We need to build a moral worldview that takes seriously what’s at stake.

By choosing wisely, we can be pivotal in putting humanity on the right course. And if we do, our great-great-grandchildren will look back and thank us, knowing that we did everything we could to give them a world that is just and beautiful