Extinction causes billions to die painful deaths and extinguishes a huge amount of future generations that have massive value

We won’t try to address those questions here. Instead, we’ll focus on this question: How bad would human extinction be?

One very bad thing about human extinction would be that billions of people would likely die painful deaths. But in our view, this is, by far, not the worst thing about human extinction. The worst thing about human extinction is that there would be no future generations.

We believe that future generations matter just as much as our generation does. Since there could be so many generations in our future, the value of all those generations together greatly exceeds the value of the current generation.

Considering a historical example helps to illustrate this point. About 70,000 years ago, there was a supervolcanic eruption known as the Toba eruption. Many scientists believe that this eruption caused a “volcanic winter” which brought our ancestors close to extinction. Suppose that this is true. Now imagine that the Toba eruption had eradicated humans from the Earth. How bad would that have been? Some 3,000 generations and 100 billion lives later, it is plausible to say that the death and suffering caused by the Toba eruption would have been trivial in comparison with the loss of all the human lives that have been lived from then to now, and everything humanity has achieved since that time.

Similarly, if humanity goes extinct now, the worst aspect of this would be the opportunity cost. Civilization began only a few thousand years ago. Yet Earth could remain habitable for another billion years. And if it is possible to colonize space, our species may survive much longer than that.

Some people would reject this way of assessing the value of future generations. They may claim that bringing new people into existence cannot be a benefit, regardless of what kind of life these people have. On this view, the value of avoiding human extinction is restricted to people alive today and people who are already going to exist, and who may want to have children or grandchildren.

Why would someone believe this? One reason might be that if people never exist, then it can’t be bad for them that they don’t exist. Since they don’t exist, there’s no “them” for it to be bad for, so causing people to exist cannot benefit them.

We disagree. We think that causing people to exist can benefit them. To see why, first notice that causing people to exist can be bad for those people. For example, suppose some woman knows that if she conceives a child during the next few months, the child will suffer from multiple painful diseases and die very young. It would obviously be bad for her child if she decided to conceive during the next few months. In general, it seems that if a child’s life would be brief and miserable, existence is bad for that child.

If you agree that bringing someone into existence can be bad for that person and if you also accept the argument that bringing someone into existence can’t be good for that person, then this leads to a strange conclusion: being born could harm you but it couldn’t help you. If that is right, then it appears that it would be wrong to have children, because there is always a risk that they will be harmed, and no compensating benefit to outweigh the risk of harm.

Pessimists like the nineteenth-century German philosopher Arthur Schopenhauer or the contemporary South African philosopher David Benatar accept this conclusion. But if parents have a reasonable expectation that their children will have happy and fulfilling lives, and having children would not be harmful to others, then it is not bad to have children. More generally, if our descendants have a reasonable chance of having happy and fulfilling lives, it is good for us to ensure that our descendants exist, rather than not. Therefore we think that bringing future generations into existence can be a good thing.

The extinction of our species—and quite possibly, depending on the cause of the extinction, of all life—would be the end of the extraordinary story of evolution that has already led to (moderately) intelligent life, and which has given us the potential to make much greater progress still. We have made great progress, both moral and intellectual, over the last couple of centuries, and there is every reason to hope that, if we survive, this progress will continue and accelerate. If we fail to prevent our extinction, we will have blown the opportunity to create something truly wonderful: an astronomically large number of generations of human beings living rich and fulfilling lives, and reaching heights of knowledge and civilization that are beyond the limits of our imagination.