This page provides some ideas on how we can make a lasting impact for future generations and why we should care about them. It’s an introduction to longtermism, the view that positively influencing the long-term future is a key moral priority of our time. Plenty of people in the effective altruism community focus on impacting the present and the near-term future, but we think longtermism provides a valuable perspective. (The text of this page is drawn from longtermism.com, 80,000 hours and effectivealtruism.org.)

We are looking ahead, as is one of the first mandates given us as chiefs, to make sure and to make every decision that we make relate to the welfare and well-being of the seventh generation to come. ... What about that seventh generation? Where are you taking them? What will they have?

—Chief Oren Lyons (1980)

What is longtermism?

Imagine burying broken glass in a forest. In one possible future, a child steps on the glass in 5 years' time, and hurts herself. In a different possible future, a child steps on the glass in 500 years' time, and hurts herself just as much. Longtermism begins by appreciating that both possibilities seem equally bad: why stop caring about the effects of our actions just because they take place a long time from now?

It’s natural to care about future generations: as a society, we may all want the lives of our children and grandchildren to go well, even before they are born. What happens when we extend the scope of our concern further than the next couple of generations? Once we consider how many generations could follow ours, the implications look striking: our actions could influence the lives of far more people than many expect.

Put simply, humanity might last for an incredibly long time. If human history were a novel, we may still be living on the very first page. This isn’t just academically interesting. We might be living through a period in which our decisions today matter for all future generations. On one hand, this could mean a time of opportunities — ensuring the values instilled in the technologies we build today reap benefits long into the future. On the other hand, we may be living through a ‘time of perils’ — where it may be possible to bring about a catastrophe severe enough to permanently curtail humanity’s potential. Yet, there are things we can start doing now to make that less likely.

You might agree that future people matter in the abstract. But it’s this point — that our actions today could meaningfully impact their lives — that can lead to the conclusion that positively influencing the long-term future should be a key moral priority of a time. This is the idea encapsulated by longtermism.

This introduction will explain these motivations behind longtermism in more depth: that future people matter morally; that there could well be an enormous number of them; and that there are things we can do today to help ensure that their lives go well.

Future people matter

Thousands, perhaps millions, of generations might follow ours. But should we care about them?

Suppose an old friend is having a hard time, and wants to speak to you on the phone. You thought they were living in the same country as you, but you learn that they recently travelled to a different continent. Would you be less inclined to help them when you learn that they’re far away from you in space? Of course not.

Many people would agree that a person’s distance from us in space doesn’t affect how much their life matters. As long as it’s just as easy to help them, a person’s needs don’t matter less just because they live farther away from us.

If people matter equally regardless of where they are born, shouldn’t they also matter equally regardless of when they are born?

From the perspective of our ancestors, we were once future people, and many generations lived between us and them. Of course, it would be strange to claim that our lives matter less simply because we were born later: our joys and pains are just as real and as important as those of the generations that came before us. People living far in the future will feel just the same when they compare the value of their lives to ours.

To be sure, there could be reasons to weigh the lives of people close to you in time and space more — perhaps because they are close friends or family, or because their closeness means you find it easier to improve their lives. But it is never the mere fact of their closeness in space or time that matters morally. The aforementioned example of burying glass in a forest, first described by the late philosopher Derek Parfit, helps illustrate this.

Humanity’s potential is large

If all goes well, human history is just beginning. Our species could survive for billions of years—enough time to end disease, poverty, and injustice, and to flourish in ways unimaginable today. But this vast future is at risk. With the advent of nuclear weapons, humanity entered a new age, where we face existential catastrophes—those from which we could never come back. Since then, these dangers have only multiplied, from climate change to engineered pathogens and [transformative] artificial intelligence. If we do not act fast to reach a place of safety, it will soon be too late.

—Toby Ord (2020)

One reason saving a human life is so valuable is because, in saving the life, you save that person's potential. The greater one’s potential, the more important it seems to protect it and do what we can to make sure it's realized — and the greater the loss if it isn't. But this doesn't just apply to individual people: humanity too can be said to have a potential — the latent possibility of an extraordinary future.

So how many people might live in the future, and how good (or bad) could their lives be? Of course, we can’t get precise estimates, but we can look for clues about our potential: how the future might very plausibly go if things go relatively well.

To begin with, the human species, Homo sapiens, has so far lasted for around 300,000 years. If humans last roughly as long as most mammals, we might expect to have at least 200,000 years remaining — nearly 1,000 future generations. Of course, humanity is not a typical mammalian species: not least because we have the technological means of preventing and recovering from threats to our own extinction.

So we might next look to the entire future of Earth. Our planet will likely remain habitable for several hundred million years. If humanity survived for just 1% of that time, there would be around half a million more generations to come after us. Assuming similar numbers of people lived per-century as in the recent past, that works out to at least a billion billion future human lives — ten thousand times the number of humans who have ever lived to date.

But will humanity stop there? Just 66 years separated the first successful heavier-than-air flight and humans walking on the Moon. Imagine how much progress we can make on spacefaring technology in a hundred or even a thousand years. It looks entirely possible for humans to eventually venture beyond Earth.

It’s important to remember that potential is not some abstract notion — it refers to the billions of people who have yet to exist. Imagine if everyone on Earth discovered they were sterile. We might be glad that no one is around to experience suffering. But there would also be no one around to witness the beauty of nature, to laugh at a joke, to listen to music, to look at a painting, and to have all the other worthwhile experiences in life. This seems like a tragic outcome. (See also, “Against neutrality about creating happy lives”.)

But you might doubt that civilization can actually survive very long or that the future would be that large. Let’s look at these considerations in a little more depth.

First, what’s not up for debate is the possibility that the future could be big. It’s a widely accepted scientific position that the Earth could remain habitable for hundreds of millions of years, and that there are at least a hundred billion planets in the galaxy. There’s also no reason to think it’s impossible that civilization could discover far more powerful technology than we have today.

Rather, what’s in doubt is the likelihood that these developments come to pass. Unfortunately there is no definitive way to estimate this likelihood. In general, the bigger you think the future could be, and the more likely you think we are to get there, the greater the value. Conversely, to the extent that you think existential risk is high, that might suggest greater opportunities to reduce that level of risk. Further, if we’re uncertain whether the future will be big, then a high priority should be to do research to reduce that uncertainty.

Of course, the survival of humanity across these vast timescales is only desirable if the lives of future people are worth living. We have already made staggering progress. But even further progress is possible, and we can hope that further scientific and medical breakthroughs will continue to improve lives in the future. Still, the world has a long way to go before it is free of immediately pressing problems. Pointing out the scope of possible, positive futures should not mean ignoring the problems of today.

We don’t know exactly what humanity's future will look like. What matters is that the future could be extraordinarily good or inordinately bad, and it is likely vast in scope — it could be home to the vast majority of most people who will ever live, and most of what we find valuable today.

Our actions could influence the long-term future

Are there things we could do now which might reliably improve or safeguard the very long-run future? For people living in long stretches of the past, the answer may indeed have been ‘no’. Yet, there are compelling reasons for thinking that this moment in history could be a point of unusual influence over humanity’s future.

One clear example is climate change. We now know beyond reasonable doubt that human activity disrupts Earth's climate, and that climate change will have devastating effects. We also know that some of these effects could last a very long time, because carbon dioxide can persist in the Earth's atmosphere for tens of thousands of years. But we have control over how much damage we cause, such as by redoubling efforts to develop green technology, building more zero-carbon energy sources, and pricing carbon emissions in line with their true social cost. For these reasons, longtermists have strong reasons to be concerned about climate change, and many are actively working on climate issues. Mitigating the effects of climate change is a king of ‘proof of concept’ for positively influencing the long-run future; but it’s not the only example.

Many people still alive today were children when humanity first learned how it might eventually destroy itself. In July of 1945, the first nuclear weapon was detonated at the Trinity Site in New Mexico. Aside from its immediate devastation, large-scale nuclear war could precipitate a severe and prolonged ‘nuclear winter’ — potentially leaving large numbers of casualties across the world from widespread crop failure. Yet, since the Trinity test, nuclear weapons proliferated into the tens of thousands, many still on hair-trigger alert today.

This suggests the possibility of an existential catastrophe — an event which permanently curtails the potential of humanity, such as by causing human extinction. Working to prevent an existential catastrophe this century makes it more likely that future generations get to live in the first place: a clear positive impact on the long-run future.

Unfortunately, nuclear weapons don’t look like the only potential cause of an existential catastrophe. Consider biotechnology. We've seen that pandemics like COVID-19 can have devastating effects. But with modern biotechnology, it will become possible to engineer pathogens to be far more deadly or transmissible than naturally occurring pathogens — threatening potentially billions of lives. And the barriers to engineering a pandemic are likely to drop even further over the coming decades: the first project to map the entire human genome took around 15 years and half a billion dollars to complete (in 2003). Today, a full genome can be sequenced in just under an hour, for around $1,000. And while DNA synthesis is still costlier, its price has already fallen by a factor of more than 1,000. (Check out Andrew Snyder-Beattie’s talk “Biotechnology and existential risk” to learn more.)

Second, consider artificial intelligence. Leading researchers of AI, such as Stuart Russell, are increasingly trying to warn us about the dangers, as well as the benefits, that advanced AI could bring. First, experts note that it is entirely plausible we will reach general-purpose, greater than human-level AI within either our lifetimes or in the lifetimes of our children. Additionally, experts note that it is difficult to align AI systems with human values, rather than having them pursue narrow objectives such as maximizing user engagement, which may be pursued single-mindedly to a fault. Artificial general intelligence could radically transform all aspects of life. Consider how humans have almost full control over other primates, such as by confining them to zoo exhibits for entertainment. Things didn’t turn out this way because we had a strength advantage, or even because we especially wanted to subjugate other primates, but on account of our intelligence. Can we be sure that things will go well if we create machines that are to us as we are to other primates? The problem of designing safe AI systems aligned with human values is a great challenge which calls for additional research. (See “The case for taking AI seriously as a threat to humanity” for a nontechnical introduction, published in Vox in 2018.)

We mention the examples of nuclear war, engineered pandemics, and unaligned AI, but a century ago, close to nobody was able to conceive of these risks at all. As we continue to invent ever more powerful technologies, perhaps that trend will continue. This century could be a time of unusual vulnerability for our highly-networked global society.

In addition to preventing existential risks, we might be able to positively influence the long-term future in other ways. For instance, we could petition to reform our political institutions to represent the interests of future generations: people who will live with the effects of policy decisions today, but who have no voice with which to influence them. This could take the form of national committees and offices (such as the United Kingdom’s All-Party Parliamentary Group for Future Generations), new voting methods, or international frameworks and panels. There is good news on this front: the secretary-general of the United Nations recently announced an agenda to consider setting up new UN projects focused on protecting future generations.

Now might be a time of unusual influence over the values that end up being held by many successive generations. History suggests that periods of rapid change are often periods where decisions about political or moral values are usually contingent and unpredictable, but then ossify over long stretches of time. And we are living in a period of rapid change, not just because of the technological advances described above, but also because the world is becoming increasingly culturally and politically globalised, and because we are living through a period of steady economic growth that looks meteoric when set in the context of the long sweep of human history.

If bad or undemocratic values soon get ‘locked-in’ for a very long time, and we fail to prevent that, then we may have failed succeeding generations. That points towards another way to positively influence the long-term future: by making it less likely that a single set of moral, cultural, or political values somehow come to dominate prematurely, before every group and perspective can be heard.

Putting things together

Many people would agree that, morally speaking, future generations deserve our moral consideration just like our own; that we do not intrinsically matter more than people in the future. This moral claim may be easy to accept partly because it’s not clear how taking it seriously could alter our priorities. Instead, it’s very natural to assume that there is nothing we could do to improve the lives of future people thousands or millions of years hence. Perhaps the effects of our efforts will quickly fade over time, or perhaps we are so uncertain about the future that we can’t be sure any of our efforts will end up being good or bad. Yet, as we’ve seen, reflecting on our moment in history suggests things we can do now to influence the long-term future — or even determine whether future generations will get to live at all.

Truly taking time to appreciate what we might achieve over the long-term makes this possibility look remarkably significant: our decisions now might be felt, in a significant sense, by billions of people yet to be born.

Concretely, this could mean working to develop better countermeasures for future pandemics, like a system for detecting novel pathogens early on. It could mean lobbying for political institutions that protect future generations, or submitting proposals to the Summit on the Future in 2023. Or it could mean doing research in economics, history, law, or philosophy to figure out other mechanisms for influencing the long-run future, or technical research making sure that powerful AI systems end up making transparent, legible decisions which are aligned with human values. (Check out “The highest-impact career paths our research has identified so far” by 80,000 Hours, a longtermist organisation which provides career advice for having a high-impact career.)

Conclusion

In summary, longtermism is the view that positively influencing the long-term future is a key moral priority of our time – because there are worthwhile things we can do about it, and future generations are worth it. The above is one argument for protecting the long-term future – thinking about sustainability and intergenerational justice are some other framings which we haven’t explored here.

Want to learn more or discuss these ideas with others? Schedule a call with a board member or for the Effective Altruism Introductory Seminar.