Let me tell you a story.
A Foreknowledge machine was built in a secret location and its existence announced to a stunned world. Suitably white-haired and bespectacled wise men were trotted out in front of TV cameras to explain how powerful security protocols and AI censors had been put in place to only allow the prediction (or non-confirmation) of positive outcomes. Politicians backed up their technical assurances with organization charts detailing an intricate oversight bureaucracy. Top military brass explained that the technology was classified to prevent would-be terrorists from using it to predict successful attacks. As further assurance against the possibility of abuse, the wise men pointed out that only a superpower could afford the astronomical amounts of energy needed to create significant CTCs. No would-be terrorist would be able to run one of these things in his cellar, even if he somehow managed to get his hands on the blueprints.
In a gesture of international good will, several very positive predictions pertaining to other countries, including historically antagonistic ones, were presented, ranging from six months to five years into the future. A sceptical and, initially, even frightened world resolved to check the outcome of the first batch of predictions half a year down the road.
They all came true.
Then the one-year predictions were fully confirmed. Then the two-year ones. By then, nobody was even holding out for the five-year check any longer; they were all too busy dreaming up wonderful predictions to submit for consideration by the rapidly swelling oversight bureaucracy. The power to select predictions for confirmation by the Machine quickly became the most sought-after perk among politicians of all stripes. And for good reason: swelling Machine-related government "business" and ensuing scandals aside, all was not only well, but better than ever. Time and again, wonderful visions were submitted to the Machine and confirmed to be part of the future, setting the plans in motion which, inevitably, led to their realization. Humanity, so it seemed, had entered a true Golden Age.
Until one day, the predictions stopped.
Not because the Machine stopped. Not because of technical problems. Everything was in order, the giant staff dedicated to operating the Machine made sure of that. They checked and rechecked absolutely everything over and over again. It was just that every single scenario submitted to the Machine was now being returned as not confirmed.
Initially they shrugged it off. A fluke, they said. Given the amount of scenarios submitted, a bad run was bound to happen at some point. Soon everything would be back to normal.
But it didn't. As time dragged on, old predictions already in the pipeline kept coming true like clockwork. Six months, one year, two years. But all new submissions came back as not confirmed.
After three years there was no denying it any longer. Something was terribly wrong, not with the Machine, but with the future. A probe was initiated to find out exactly where. A sequence of simple predictions so trivial they would never have made it through the usual selection process was submitted, spaced in time according to a simple golden mean algorithm. The result was incontrovertible: all predictions, even the most trivial, failed after The Date. Although they certainly tried, this was something not even the mighty security apparatus surrounding the Machine could keep under wraps. Soon the whole world was talking of nothing but The Date.
The Date. The day beyond which nothing good would happen. For all practical purposes, the end of the world.
Religion bounced back from an all-time low to become more popular than ever. Preachers were the new rock stars. Scientists appeared in heated televised debates on how the world would end, waving their new popular tomes, fresh off the printing presses, at each other. Asteroid impact, one said. Black hole, countered another. Alien invasion, opined a third. Antibiotic-resistant, airborne pandemic, suggested a particularly pedestrian one. Financial markets crashed.
When paparazzi caught a giggling President lying on his back on the White House lawn, dressed in an old "No Future" T-shirt and smoking a haphazardly hand-rolled cigarette, it was all over. People stopped going to work, then stopped leaving their houses altogether. Store shelves gaped empty as the intricate supply chain which had supported industrial civilization collapsed. Gangs formed, looted what was left to loot, but mostly concentrated on killing each other off. Suicide rates shot through the roof.
When The Date finally rolled along, there was nobody left to notice.
Ten thousand years later, give or take a few millennia, an alien probe flying by the solar system snapped a sequence of photos showing the ruins of Earth's giant cities and the still perfectly preserved Machine on the far side of the moon. The probe's AI was only sophisticated enough to recognize and document the remnants of a planetary-scale technological society, but the electronic archivist at the receiving end of its data stream had no problem recognizing the signs. It had seen the same pattern many times before.
Earth was filed under "Killed by self-fulfilling prophecy".
