Can You Calculate the Life Expectancy of Civilization?

Can You Calculate the Life Expectancy of Civilization?

A lightly edited version of a letter emailed to a group of physicists, Catholic Church officials, government leaders, and other thought leaders
on May 5, 2026, Day 67 of the Iran War 

Greetings to all,

I hope that everyone is well. If anyone experienced a loss recently or is worried about an ailing relative, as I suspect may be the case for one possible reader, you have my best wishes. I have seen encouraging signs recently, including the abandonment of plans to build a soccer stadium in the city of Albany, New York, USA, where the local branch of the state university already has sufficient spare soccer facilities to accommodate a local professional franchise that could pay a fee for their use, supporting the university in a lean period for institutions of higher education in the United States; support given by the priest at the Cathedral of the Immaculate Conception in Albany for childfreedom by choice among the laity, expressed in his acknowledgement of unmarried life as an option no less valid than marriage or holy orders; the destruction of the geopolitical power of the United States in a long process that has accelerated since the onset of the liquidation of the Gaza ghetto; and the decision by His Holiness Pope Leo to de-emphasize sexual morality among Church priorities. Starting from positive circumstances such as these, what is the most important idea with which to nurture the values necessary for our survival over the next few decades as a species capable of large-scale coordinated activity?

First, let’s be clear on the fact that our civilization is gravely endangered. Looking solely at nuclear weapons, Nobel physics laureate and Breakthrough Prize recipient David Gross recently estimated the expected lifespan of our civilization at 35 years. To arrive at this figure, he estimated a 2% chance each year of large-scale thermonuclear war. The standard calculation of expectation value in this situation seeks the number of years until the probability of large-scale nuclear war having occurred equals ½. Since large-scale nuclear war becomes impossible once large-scale nuclear war has occurred, owing to the collapse of civilization in nuclear winter, you can’t have more than one such war in the calculation. Thus, you use the 0.02 estimated probability of such a war in a given year to find a probability of 0.98 that no such war will occur in any given year. Then you employ the fact that the probability of there being no such war over several years is the product of the annual probabilities of there being no such war. For there to be a probability of at least ½ that such a war has occurred in N years, there must a probability of no more than ½ that no such war has occurred in the N years, giving

½ = 0.98^N,

the solution to which is N = 35.

I gave every fact you need to understand Gross’s result, but I deliberately refrained from going out of my way to make understanding the derivation easy. If the calculation is unclear to you, I assert that you do not understand how to think about probability and thus are ill-equipped to reason about the future. This is one reason I think that physicists, all of whom understand the calculation, are shirking their responsibility to society and their own children when they fail to scream at the top of their lungs every waking moment, to glue their hands to buildings, or to clear their throats politely and whisper, “Unless you change radically, you’re probably doomed,” as David Gross did when he collected his newsworthy $3 million Breakthrough Prize. I’m guessing that every physicist paying attention, like all the richies with survival bunkers in New Zealand, has their own plan. If you struggle to understand probability, maybe talk to a physicist about the survival prospects of you or your children beyond 2060.

Mind you, under Gross’s assumption of a 2% annual threat of large-scale nuclear war, the actual life expectancy of our civilization is no more than 35 years. Besides nuclear weapons and the fact that most of our leaders seem not to understand probability, there are other, mutually reinforcing existential risks to our civilization. Artificial intelligence scares many informed people more than nuclear weapons. There’s also the climate crisis, biodiversity loss, soil depletion, growing wealth inequality, groundwater depletion, weaponization of finance, undirected existential fear, etc. Welcome to Planet Earth, if your head’s been in one of the realities curated to pacify you.

You might ask why I bother writing so assiduously if there’s so little hope. One reason is that I propose to create a message that would penetrate the barrier to knowledge transmission formed by the collapse of civilization. Another is that the maximum of hope exists right now, because hope wanes with every moment we delay. Furthermore, I’m a complex systems scientist, so I know that a collection of many autonomous agents can turn ponderously, like the Titanic, or on a dime, like a flock of sheep that catches scent of a wolf or is warned even sooner by the shepherd, who happens to be getting his affairs in order lately and may have more time to devote to his job than he’s had in a long while.

Again, what idea could trigger systemic change, getting the flock to reverse course by getting individual sheep to turn around and move away from the edge of the cliff? Of great importance is the fact that too much of a good thing is bad, especially in a system subject to existential threats that can all be traced back, ultimately, to consumption pressure, or overutilization of resources. We see the message warning against too much of a good thing in the Gospel of John, when Jesus insists that Peter content himself with a foot washing and forgo the hot carnauba wax; in the story of Noah’s ark, which includes God limiting the lifespan of people, a flood, and the creation of a family rift in an episode of drunkenness, instances of life, water, and wine, good things all, becoming bad in excess; and in the account of the imam, delivered at the recent interfaith gathering on Earth as our common home conducted at Siena University, of the mess created by worshipers overzealously performing wudu, the ritual cleansing, especially in the context of a religion founded in a desert.

In our lives today, we see too much economic activity destroying the natural world, too much work for money driving down wages and exacerbating wealth inequality, too much desire for self-preservation keeping people who surely know better in line behind maniacally destructive leaders, and too much concern for short-term safety paralyzing systems that demand rapid change in order to have much chance of medium-term survival.

The risks and harms of permitting there to be too much of a good thing fall into a larger category, the disadvantages of what one ordinarily wants. Wise folk are driven by awareness of these disadvantages to contemplate the virtues of what they oppose, and vice versa. For example, religions with which I’m familiar rarely praise darkness, though we use it to our benefit for many purposes and suffer on occasion from too much light. Wise folk value darkness to the appropriate degree and seek darkness when its value exceeds the value of light.

The merits of plans a particular person finds counterintuitive can be made easier to perceive and act upon when that person is encouraged to perform a simple procedure, namely devising what they consider to be a strong argument against the course of action they favor or in favor of an opposing plan. Certainly, no leader should make an important decision without engaging in this mental exercise, as the debacle for the United States of the Iran War, or USISIR War, would seem to make clear if we assume that United States leaders are loyal to the United States, even leaders who had a falling out with information broker and possible blackmailer Jeffrey Epstein.

As an aside, I encourage leaders to investigate what meretricious philosophies, based on cutting-edge science, especially fundamental physics, Epstein may have been disseminating into the ears of powerful and wealthy people Epstein entertained. As everyone knows, Epstein insinuated Epstein into scientific circles, and certain fashionable ideas in fundamental physics can easily serve as pretexts for nihilistic or sybaritic philosophies. Some scientists whom I assume to be good and decent people, as well as some other scientists, arrive at philosophies that seem to me to deny the existence of personhood with a certitude that smacks of either intellectual arrogance or neurodivergence. If we knew more about what people actually think, we might be able to correct false impressions about science and undermine belief in destructive models of reality inspired by those false impressions, for many people, including some scientists, are confused about what science has actually established. Simple fact checking could heal many hearts.

I’m going to break off here. A story from my life that I'd planned to tell can wait. Perhaps read the interview with David Gross, skipping his thoughts on his presumably prizeworthy and amusingly named heterotic string theory, of which I’ve just become aware, and focusing on the interviewer’s reaction to Gross’s estimate of the life expectancy of the interviewer’s 6- and 11-year-old children. Then please apply the technique of arguing against your currently planned pattern of behavior, to discern whether you've entered a realm where you're endangered by too much of what you ordinarily consider good, or whether you ought to be screaming or gluing or whispering to avert the collapse of our civilization, or whether you require the services of a physicist to learn how to think about the future.

Yours in God(s), regardless of models of God(s),
James