I used to think you could predict the future. In "Profiles of the Future," Arthur C. Clarke made it seem so easy. And so did all those other experts who confidently predicted the paperless office, the artificial intelligentsia who for decades predicted "human equivalence in ten years," the nanotechnology prophets who kept foreseeing major advances toward molecular manufacturing within fifteen years, and so on.
Mostly, the predictions of science and technology types were wonderful: space colonies, flying cars in everyone's garage, the conquest (or even reversal) of aging. (There were of course the doomsayers, too, such as the population-bomb theorists who said the world would run out of food by the turn of the century.)
But at last, after watching all those forecasts not come true, and in fact become falsified in a crashing, breathtaking manner, I began to question the entire business of making predictions. I mean, if even Nobel prizewinning scientists such as Ernest Rutherford, who gave us essentially the modern concept of the nuclear atom, could say, as he did in 1933, that "We cannot control atomic energy to an extent which would be of any value commercially, and I believe we are not likely ever to be able to do so," and be so spectacularly wrong about it, what hope was there for the rest of us?
And then I finally decided that I knew the source of this incredible mismatch between confident forecast and actual result. The universe is a complex system in which countless causal chains are acting and interacting independently and simultaneously (the ultimate nature of some of them unknown to science even today). There are in fact so many causal sequences and forces at work, all of them running in parallel, and each of them often affecting the course of the others, that it is hopeless to try to specify in advance what's going to happen as they jointly work themselves out. In the face of that complexity, it becomes difficult if not impossible to know with any assurance the future state of the system except in those comparatively few cases in which the system is governed by ironclad laws of nature such as those that allow us to predict the phases of the moon, the tides, or the position of Jupiter in tomorrow night's sky. Otherwise, forget it.
Further, it's an illusion to think that supercomputer modeling is up to the task of truly reliable crystal-ball gazing. It isn't. Witness the epidemiologists who predicted that last year's influenza season would be severe (in fact it was mild); the professional hurricane-forecasters whose models told them that the last two hurricane seasons would be monsters (whereas instead they were wimps). Certain systems in nature, it seems, are computationally irreducible phenomena, meaning that there is no way of knowing the outcome short of waiting for it to happen.
Formerly, when I heard or read a prediction, I believed it. Nowadays I just roll my eyes, shake my head, and turn the page.