MADness

The Evolutionary Logic of Nuclear Deterrence. Part II

In Part I of this Skeptic 3-part series, Arena, Writ Past, I outlined the evolutionary logic of aggression and violence, demonstrating that these are, in the popular computer science idiom, features of our programming, not bugs. Organisms, including humans, evolved emotions that direct us to strike back if hit, to retaliate if exploited, and to avenge wrongs committed against us. If we didn’t have these moral emotions our more altruistic ancestors would have been outcompeted by free riders, exploiters, and bullies. Then again, if you’re too self-oriented and exploitative, you’ll be punished by others, so we evolved a balanced suite of emotions—too selfish and other people will punish you; too selfless and other people will exploit you. Cultural norms, social expectations, and political laws turn up or down the dials of our inner demons and better angels, and conflicts are thus a normal part of the human condition.

This brings us to moral dilemmas in which what we do very much depends on what others do, in a game theoretic interaction with implications for large-scale human conflict, from civil wars to international wars, including and especially nuclear war, a scenario so unimaginably destructive that it is the only viable candidate for a true existential threat to our civilization, if not the species. In this week’s episode of The Michael Shermer Show I spoke with journalist Annie Jacobsen, author of Area 51, Operation Paperclip, The Pentagon’s Brain, Phenomena, and Surprise, Kill, Vanish, whose new book, Nuclear War: A Scenario, is first among equals of the many excellent works on nuclear war that I’ve read. (These include Richard Rhodes’s nuclear tetralogy The Making of the Atomic Bomb, Dark Sun, Arsenals of Folly, and Twilight of the Bombs, Eric Schlosser’s Command and Control, Fred Kaplan’s The Bomb, Martin Sherwin’s Gambling with Armageddon, Daniel Ellsberg’s The Doomsday Machine, and John Hershey’s Hiroshima, among others.)

As Annie revealed in our podcast conversation, her book has been optioned by Legendary Entertainment and the renowned Dune director Denis Villeneuve, to be made into a major motion picture drama whose effects could (and hopefully will) be comparable to what The Day After television drama did to alter the thinking of President Ronald Reagan, who before seeing the film was a hawkish nuclear Cold Warrior. As Annie noted to me in an email: “As POTUS, Reagan watched it too (private screening at Camp David) and had an epiphany — i.e. the Reagan Reversal that led to the Reykjavík summit. Nukes down from 70,000 all time high to ~12,500 today.”

Here is how Jacobsen opens her riveting narrative:

A 1-megaton thermonuclear weapon detonation begins with a flash of light and heat so tremendous it is impossible for the huan mind to comprehend. One hundred and eighty million degrees Fahrenheit is four or five times hotter than the temperature that occurs at the center of the Earth’s sun.

In the first fraction of a millisecond after this termonuclear bomb strikes the Pentagon outside Washington, D.C., there is light. Soft X-ray light with a very short wavelength. The light superheats the surrounding air to millions of degrees, creating a massive fireball that expands at millions of miles per hour. Within a few seconds, this fireball increases to a diameter of a little more than a mile (5,700 feet across), its light and heat so intense that concrete surfaces explode, metal objects melt or evaporate, stone shatters, humans instantaneously convert into combusting carbon.

The five-story, five-sided structure of the Pentagon and everything inside its 6.5 million square feet of office space explodes into superheated dust from the initial flash of light and heat, all the walls shattering with the near-simultaneous arrival of the shock wave, all 27,000 employees perishing instantly.

Not a single thing in the fireball remains

Nothing.

Ground zero is zeroed.

The effects of just the initial blast of a 1-megaton thermonuclear bomb goes on like this for page after agonizing page. Annie Jacobsen’s narrative is meant to shock us into action, and hopefully it will. But what action? As she explained to me in our conversation, that is not her domain of expertise, so let me turn to the literature on game theory and the madness of Mutual Assured Destruction (MAD) that has—thus far anyway—kept nuclear armageddon away from our combustable doorsteps.

The Game Theoretic Logic of Moral Dilemmas

The logic of our moral emotions has been worked out by game theorists in the Prisoner’s Dilemma paradigm. Here’s the scenario: you and your partner are arrested for a crime and you are held incommunicado in separate prison cells. Neither of you wants to confess or rat on the other, but the D.A. gives each of you the following options:

1. If you confess but the other prisoner does not, you go free and he gets three years in jail.

2. If the other prisoner confesses and you do not, you get three years in the slammer and he goes free.

3. If you both confess, you each get two years.

4. If you both remain silent, you each get a year.

Figure 1 below, called a game matrix, summarizes the four outcomes.

With those outcomes, the logical choice is to defect and betray your partner. Why? Consider the choices from the first prisoner’s point of view. The only thing the first prisoner cannot control about the outcome is the second prisoner’s choice. Suppose the second prisoner remains silent. Then the first prisoner earns the “temptation” payoff (zero years in jail) by confessing but gets a year in jail (the “high” payoff) by remaining silent. The better outcome in this case for the first prisoner is to confess. But suppose, instead, that the second prisoner confesses. Then, once again, the first prisoner is better off confessing (the “low” payoff, or two years in jail) than remaining silent (the “sucker” payoff, or three years in jail). Because the circumstances from the second prisoner’s point of view are entirely symmetrical to the ones described for the first, each prisoner is better off confessing no matter what the other prisoner decides to do.

Those preferences are not only theoretical. When test subjects play the game just once or for a fixed number of rounds without being allowed to communicate, defection by confessing is the common strategy. But when testers play the game for an unknown number of rounds, the most common strategy is tit-for-tat: each begins cooperating with the prior agreement by remaining silent, then mimics whatever the other player does. Even more mutual cooperation can emerge in a many-person prisoner’s dilemma, provided the players are allowed to play enough repeated rounds to establish mutual trust. But the research shows that once defection by confessing builds momentum, it cascades throughout the game.

Figures 2 and 3 below show the game matrices that favor cheating and that favor playing by the rules.

In game theory, if no player has anything to gain by unilaterally changing strategies, the game is said to be in a Nash equilibrium. The concept was developed by the mathematician John Forbes Nash, Jr., who was portrayed in the film A Beautiful Mind. In the second scenario—the one that leads to a stable Nash equilibrium—players must not feel like suckers for following the rules. In the game of prisoner’s dilemma, lowering the temptation to confess and raising the payoff for keeping silent if the other prisoner confesses increases cooperation. Giving players the chance to communicate before they play the game is the most effective way to increase their cooperation.

In order for there to be cooperation between competing agents in a game (or nations in the real world—see below), there need to be rules, and the rules must be enforced. With our complex moral nature, people need to be encouraged to do the right thing and discouraged from doing the wrong thing—the proverbial carrots and sticks.

The Evolutionary Logic of Deterrence

In game theoretic models of international relations, the other player is another nation state, and if they have nuclear weapons, and so do you, it can lead to an arms race resulting in something like a Nash Equilibrium, such as the one that kept the US and USSR in a Cold War nuclear freeze called a “balance of terror,” or Mutual Assured Destruction—MAD—for nearly three-quarters of a century. Let’s look at how this worked, and what more we can do to further reduce the risks of nuclear war based on what we know about human nature and the logic of deterrence.

Popular films such as Fail Safe and Dr. Strangelove reinforced the counterpoint to deterrence, namely that one slip-up, or false-positive identification leading to a counterstrike, or a madman obsessed with precious bodily fluids, can lead to nuclear armageddon. That hasn’t happened yet. MAD has worked because neither side has anything to gain by initiating a first strike against the other nation—the retaliatory capability of both is such that a first strike would most likely lead to the utter annihilation of both countries (along with much of the rest of the world). Here is how Secretary of Defense Robert S. McNamara described it:

It’s not mad! Mutual Assured Destruction is the foundation of deterrence. Nuclear weapons have no military utility whatsoever, excepting only to deter one’s opponent from their use. Which means you should never, never, never initiate their use against a nuclear-equipped opponent. If you do, it’s suicide.

The logic of deterrence was first articulated in 1946 by the American military strategist Bernard Brodie in his appropriately titled book The Absolute Weapon: Atomic Power and World Order, in which he noted the break in history that atomic weapons brought with their development: “Thus far the chief purpose of our military establishment has been to win wars. From now on, its chief purpose must be to avert them. It can have almost no other purpose.”

As Dr. Strangelove (Peter Sellers) explained in Stanley Kubrick’s classic Cold War film (in the famous war room scene where fighting is not allowed): “Deterrence is the art of producing in the mind of the enemy the fear to attack.” Said enemy, of course, must know that you have at the ready such destructive devices, and that is why “The whole point of a doomsday machine is lost if you keep it a secret!”

Dr. Strangelove was a black comedy that parodied MAD by showing what can happen when things go terribly wrong, in this case when General Jack D. Ripper (Sterling Hayden) becomes unhinged at the thought of “Communist infiltration, Communist indoctrination, Communist subversion, and the international Communist conspiracy to sap and impurify all of our precious bodily fluids,” leading him to order a nuclear first strike against the Soviet Union. Given this unfortunate incident, and knowing that the Russians know about it and will therefore retaliate, General “Buck” Turgidson (George C. Scott) pleads with the president to go all out and launch a full first strike:

Mr. President, I’m not saying we wouldn’t get our hair mussed, but I do say no more than ten to twenty million killed, tops, uh, depending on the breaks.

He wasn’t far off from real projected casualties (Kubrick was a student of Cold War strategy), as computed by Robert McNamara:

What kind of amount of destruction must we be able to inflict upon the attacker in the retaliation to insure that he would indeed be deterred from initiating such an attack? In the case of the Soviet Union, I would judge that a capability on our part to destroy, say, one-fifth to one-fourth of their population and one-half of her industrial capacity would serve as an effective deterrent.

When he spoke these words in 1968 the population of the U.S.S.R. was about 128 million, which translates to 25-32 million dead. Staggering.

In The Moral Arc I considered the implications of a nuclear exchange, quoting from a 1979 report from the Office of Technology Assessment for the U.S. Congress, entitled The Effects of Nuclear War, which estimated that around 160 million Americans would die in an all-out Soviet first strike. (Compare that to the the CDC’s tally that a little over one million Americans died of Covid-19, an event of life-changing consequences.) The report then lays out a scenario for what would happen to one city the size of Detroit if it were hit by a 1-megaton nuclear bomb (1-megaton equals 1,000 kilotons, or a thousand tons of TNT; the Hiroshima Little Boy bomb had a yield of 16 kilotons):

A 1-Mt [megaton] explosion on the surface leaves a crater about 1,000 feet in diameter and 200 feet deep, surrounded by a rim of highly radioactive soil about twice this diameter thrown out of the crater. Out to a distance of 0.6 miles from the center there will be nothing recognizable remaining …. Of the 70,000 people in this area during nonworking hours, there will be virtually no survivors. … Individual residences in this region will be totally destroyed, with only foundations and basements remaining. … Whether fallout comes from the stem or the cap of the mushroom is a major concern in the general vicinity of the detonation because of the time element and its effect on general emergency operations. … The near half-million injured present a medical task of incredible magnitude. Hospitals and beds within 4 miles of the blast would be totally destroyed. Another 15 percent in the 4- to 8-mile distance range will be severely damaged, leaving 5,000 beds remaining outside the region of significant damage. Since this is only 1 percent of the number injured, these beds are incapable of providing significant medical assistance. … Burn victims will number in the tens of thousands; yet in 1977 there were only 85 specialized burn centers, with probably 1,000 to 2,000 beds, in the entire United States.

The report goes on like this for pages. Multiply those effect by 250 (the number of American cities believed to be targeted by the Soviet Union) and you get a visceral sense of the report’s stark conclusion: “The effects on U.S. society would be catastrophic.”

You don’t say.

Deterrence has worked so far—no nuclear weapon has been detonated in a conflict of any kind since August, 1945—but it would be foolish to think of deterrence as a permanent solution. In addition to the immediate deaths due to the explosion, heat, and radiation, there are serious long-term effects explored by the astronomer Carl Sagan and the atmospheric scientist Richard Turco in their book entitled A Path Where No Man Thought, based on a technical paper in Science by Richard Turco, Brian Toon, Thomas Ackerman, James Pollack, and Carl Sagan. They are now known as the doomsday sounding “TTAPS” authors, who estimated “In a nuclear ‘exchange,’ more than a billion people would instantly be killed. But the long-term consequences could be much worse.” Smoke, soot, and debris from the fires caused by an all-out thermonuclear war would render the planet nearly uninhabitable by blocking the sun’s radiation and triggering another ice age. They called this scenario “nuclear winter,” which has been challenged by some scientists as highly unlikely, or that at most it would lead to a “nuclear autumn” instead of winter. But Jacobsen interviewed Brian Toon, who admitted “Our first models said nuclear winter would last about one year. New data suggests the Earth’s recovery time would be more like ten years.” So, if anything, the TTAPS authors’ calculations of consequences was an underestimate.

Regardless of the details of that particular debate, in their book Sagan and Turco outlined a realistic proposal to reduce the world’s nuclear stockpile to a level of Minimum Sufficiency Deterrence (MSD)—large enough to deter a nuclear first strike, but small enough so that if a slipup or a madman detonated a weapon it would not result in an all-out nuclear winter (or autumn).

Since the end of the Cold War, it has become strategically less necessary and economically less desirable to retain so many nuclear weapons, resulting in a dramatic decline in stockpiles, as evidenced in Figure 4 below, showing a dramatic decline from a peak in the mid 1980s of around 70,000, to around 12,500 total nuclear warheads today, here graphed by Our World in Data.

That’s still a long way from the figure of about 1,000 weapons that Sagan and Turco estimated for MSD, so in Part III of this series I will consider how to make further progress away from the MADness of deterrence.

Michael Shermer is the Publisher of Skeptic magazine, Executive Director of the Skeptics Society, and the host of The Michael Shermer Show. His many books include Why People Believe Weird Things, The Science of Good and Evil, The Believing Brain, The Moral Arc, and Heavens on Earth. His latest book is Conspiracy: Why the Rational Believe the Irrational. His next book is: Truth: What it is, How to Find it, Why it Matters, to be published in 2025.