[The original was published in Portuguese. Sorry if it's not so great in English]

Ancient Stoics, such as the Roman emperor Marcus Aurelius and the former slave Epictetus, had a mental exercise called premeditatio malorum – the negative visualization, or "anticipation of adversity." It's about reflecting on what we fear may happen, such as illness, suffering, the death of loved ones, etc. For these philosophers, in addition to preparing for the worst, this allows us to focus on what is most relevant and that has value even if our fears materialize. Also, it would help to see that even in the worst situations, we still have control over our thoughts and attitudes, being able to act in accordance with virtue – which, for them, is what really matters.

I wonder if this practice would still be recommendable for the present day. Even if our lives are, on average, significantly better than those of Ancient Rome, it's plausible that this exercise tends to evoke more anxiety than serenity. A Roman citizen usually feared dishonor, slavery, or even the destruction of his city (and these risks were very concrete). In such cases, another exercise recommended by the Stoics is to take a cosmopolitan, or even "cosmic" perspective, seeing ourselves and our surroundings as part of a larger whole (of the human species and of a world that persists after we’ve passed away) thus diminishing the relative importance of these fears. But the idea of a well-ordered universe of ancient philosophy has been buried by modern science, and today any of us can conceive of what Prof. Alexey Dodsworth, following Hans Jonas, calls sumum malum, the very collapse of civilization and the extinction of mankind – like the simple-minded fisherman played by Max von Sydow in Winterlight, who despairs at the possibility of nuclear war. We don't even need to see a Bergman movie to have a similar existential crisis; many have experienced something like this during the recent pandemic, and others have a similar sentiment about the looming climate catastrophe (like Jonathan Franzen’s What if we stopped pretending?). Even more dramatic scenarios are shown in  recent pop TV shows, such as Carol and the End of the World and the long-awaited The Three-Body Problem.

Rather than offering solace, contemporary philosophers point out that we have even more to lose than the billions of lives that would be destroyed. In What We Owe the Future, Will MacAskill teaches that we would also lose all the potential value of the future of human civilization – the countless lives that could exist, in situations as different from ours as we are today different from the ancient Romans. Samuel Scheffler, in Death and the Afterlife, argues that since much of the value of our lives depends on things that will occur after our deaths, the prospect of future extinction would rob us of that value. Imagining that other humans will still be around after I am gone allows me to give relatively less importance to my own limited individual existence, and more to what is "beyond myself" – which comforts me about my mortality, and makes me want to be remembered in a positive way by future generations. That would be lost if it turned out that we are the last generation. 

On the other hand, as everyone (Stoic or not) would agree, thinking seriously about the worst can help one avoid it. Before joining wealthy survivalists in New Zealand (as described by Evan Osnos’s Doomsday Prep for the Super-Rich), it might be interesting to discuss the subject with risk-management bureaucrats. In the U.S., since a year ago, a law has required the Department of Homeland Security and the Federal Emergency Management Agency to systematically analyze global catastrophic risks. Similarly, the UK's National Risk Assessment also includes some of these threats, however unlikely they may be.  In Brazil, we could reflect on the issue in discussions on the Climate Plan and the National Plan for Civil Protection and Defense, and we could take advantage of the G20 meetings and, next year, COP-30 to address the issue with other countries.

In addition, a cooler assessment allows us to measure how unlikely societal collapse and extinction really are. In most catastrophic scenarios, despite all the suffering, there would still be people with lives worth living (at least from their perspective – many of us are too accustomed to the comforts of modern civilization to appreciate the Mad Max-like post-apocalyptic routine). This suggests the importance of preserving some aspects of our culture that can positively affect the future trajectory of society – such as biodiversity, natural resources, technologies, and even ideas and cultural goods.

Even our extinction does not necessarily imply the destruction of all intelligent life; if life exists on other planets, it would likely not be affected. This has been pointed out as the main reason for extraplanetary expansion: to create space colonies as a "plan B". However, in A City on Mars, the geek couple Zach and Kelly Weinersmith argue that, despite all the hype, early expansion could carry more risks than advantages — especially if, for instance, it increased the chances of global conflict. For quite a while, there shall be no "Planet B" for us.

But now consider Fermi’s paradox: if the galaxy has been around for so long, and if there are so many stars and planets out there, it's likely that life has arisen elsewhere, and that it has expanded; but then, why haven't we found a sign of it? One possibility, explored in the books that gave rise to Netflix’s Three-body problem, is that the universe is a dangerous place; sooner or later, advanced species would be struck by what astrobiologists call the Great Filter. Perhaps intelligent life is something fragile, or it has a tendency to self-destruct; this is what we could conclude if we found evidence of an extinct non-human civilization. Therefore, if (or rather, when) we ever go extinct, it would be interesting that some human records survive - so that if at some point there is another intelligent life in the universe, it would have a chance of finding them. In that case, such records would be the last (and perhaps most important) impact humanity would have on the universe, conveying, however implicitly, a benevolent warning: "We existed, and we perished; it may have happened to others, and someday it may happen to you." This thought makes me want to look at the stars more often.

Finally, I wish to remark that I sympathize with those pragmatic minds who might feel some aversion to the speculative character of these reflections; if you are one of them, I thank you for your patience in reading me to the end. These people are protected from the anxiety that this exercise can generate; on the other hand, they may be more susceptible to despair or confusion when the next "imponderable" occurs, like von Sydow's fisherman. I certainly wouldn't want everyone to think the same way; but if at least those in power seriously considered (or listened to those who do) the risk of global catastrophes, we could feel safer – and perhaps even less divided. And this I grant to the Stoics: I feel great admiration, even envy, for the sane person who can seriously contemplate the possibility that the world will end, without feeling regrets – knowing that even this does not subtract from the value of their actions.