› 2) Don’t insult your opponent. Start with the premise that people aren’t stupid, whether they know science and math or not. If you insult them you’ll be seen as arroganti and you’ll lose the argument.

› 3) The best attack on Carter is the notion that the cosmos is radically indeterministic. You can argue from quantum physics to justify thisi if you can keep your audience with youi or from’ free will if not. There is no way, even in principle, to say how many humans might exist in the future. So the Carter analogy between humankind and balls in an urn breaks down.

› 4) If your audience is sophisticated enoughn remind them that the whole argument is based on Bayesian statistics, which is a technique to refine probabilities of an event given a knowledge of prior probabilities. But in this case we have no prior probabilities to work with (we can only guess about the long-term future of humankind). So the Bayesian technique can’t be valid.

› 5) Reduce the argument to the trivial. It’s trivially obvious that people discussing Carter’s argument find themselves alive today, not hundreds of years in the future. But nothing nontrivial follows from a triviality. Since no humans of the future are yet alive, it isn’t in the least surprising that we aren’t among them

› 6) You could try a reductio ad absurdum. On any scale an exponential curve looks the same. You always seem to be at the beginning, minuscule compared to what is to come. So the catastrophe will always be just over the horizon. (Of course this argument falls down unless the exponential curve of the human population really does extend to infinity. Any finitude and something like Carter comes into play- But you don’t have to mention that unless challenged.)

› 7) Appeal to common sense. Look back in time. A human of, say, A.D. 1000 would likewise have been sitting on top of an exponential curve reaching back to the Paleolithic. Would she have been correct to deduce she was in the last generations? Of course not, as we can see with retrospect. (You may find Carter proponents countering this one by saying this is a false analogy, humanity today faces far graver extinction threats than in A.D. 1000 because of our technological advancement! the way we have filled up the Earth, etc.

And it took our modern-day sophistication to come up with the Carter argument in the first place. So we have formulated the Carter prophecy at precisely the moment it is most applicable to us. But then you can argue that they are appealing beyond the statistics.)

‹continuing list snipped›

› Rememberi though! None of the counterarguments are definitive. You may find yourself up against somebody with as much or more understanding of statistics than you. In that case, escalate the argument until you blind the general audience with science.

› The objective here isn’t to disprove Carter — that may be impossible. You can hole the argument but you can’t sink it, and anyhow the one true invalidation will be our continued survival in 201 years — but we must stop this ludicrous panic over Carter before it eats us all up like a brush fire.

Maura Della

Doom soon was all rather difficult to believe, a month after Cornelius had gone public, as Maura endured the usual Potomac hell: breakfasts with reporters, morning staff meetings, simultaneous committee meetings to juggle, back-to-back sessions with lobbyists and constituents, calls, briefings, speeches, receptions, constant implant-pager tingles to make quorum calls and votes on the run. And then there were the constituency issues she couldn’t neglect: “casework” — distributing small favors, funded by the federal pork barrel and otherwise — and targeted mail and fund-raising shots and chat-room surgeries and online referenda and appearances, in person, e-person, or simulated. It was all part of the constant campaign, a treadmill she knew she couldn’t fall off of if she expected to get elected again.

But this was just the general grind of federal government. It was as if illegal rocket launches in the desert, the dire warnings of doom, had never happened.

The federal government think tanks who had tried to flesh out the Carter catastrophe hypothesis had provided her with some gloomy reading.

On the one hand, nobody could definitively undermine the argument itself on philosophical or mathematical grounds. No tame expert would stand up and say he or she could demonstrate the damn thing was bullshit in simple enough terms for the president to deliver to the nation, the panicking world.

On the other hand the think tanks could come up with a lot of ways the world might end.

War, of course: nuclear, biological, chemical, A disaster from genetic engineering, malevolent or otherwise. The report recalled one near-miss in the early ‘OOs in Switzerland, concerning a birth-control vaccine. A genetically altered salmonella bacterium had been supposed to cause a temporary infection in the female gut that triggered antibodies against sperm. It had, of course, mutated and gotten out of control. A hundred thousand women had been rendered permanently infertile before the bug was stopped.

Environmental catastrophes: the continuing collapse of the atmosphere’s structure, the greenhouse effect.

Ecoterrorism: people waging war both for and against the environment. Witness the ground-to-air missile that had recently brought down the Znamya, the giant inflatable mirror that should have been launched into orbit to light up the night sky over Kiev. Witness similar attacks on the reef balls on the Atlantic ocean shelf, the giant concrete hemispheres intended to attract fast-growing algae and so soak up excess atmospheric carbon dioxide. Maura was grimly amused to see that Bootstrap had been maj or investors in both these proj ects.

But much worse was possible. The environment was essentially unstable, or at least only quasi-stable. If somebody found a way to tip that stability, it might only need a small nudge.

That was the man-made stuff. Then there were natural disasters. That hoary old favorite, the asteroid strike, was still a

candidate.

And the Earth, she read, was overdue for a giant volcanic event, one of a scale unseen in all of recorded history. The result would be a “volcano winter” comparable to nuclear-war aftermath.

Or the radiation from a nearby supernova could wipe the Earth clean of life; she learned that the Earth, in fact, was swimming through a bubble in space, a bubble blown clear in the interstellar medium by just such a stellar explosion.

And here was something new to her: perhaps a new ice age would be triggered by the Earth’s passage through an interstellar cloud.

The report concluded with more outlandish speculations. What about annihilation by extraterrestrials? What if some alien species was busily transforming the Solar System right now, not even aware that we existed? .

Or how about “vacuum decay”? It seemed that space itself was unstable, like a statue standing on a narrow base. It could withstand small disturbances—”small,” in this case, including such things as galactic-core explosions — but a powerful enough nudge, properly applied, could cause the whole thing to tip over into… well, a new form. The take-home message seemed to be that such a calamity would be not just the end of the world, but the end of the universe.

Et cetera. The list of apocalypses continued, spectacular and otherwise, at great length, even to a number of appendices.

The report authors had tried to put numbers to all these risks. The overall chance of species survival beyond the next few centuries it put as 61 percent — the precision amused Maura — a result they described as “optimistic.”

That wasn’t to say the world would be spared all the disasters; that wasn’t to say the human race would not endure death and suffering on giant scales. It wasn’t even a promise that human civilization in its present form would persist much longer. It was just that it was unlikely that the world would encounter a disaster severe enough to cause outright human extinction. Relatively unlikely, anyhow.