A Century of Progress by Fred Saberhagen

hadn’t told him, back in Eighty-four, that he had to be wrong every time someone in the past asked his opinion of the future.
    They had cautioned him against setting up as any kind of seer or fortune teller. And had added something like: “Don’t rely, even for your own purposes, on your knowledge of history being correct in every detail. You may remember perfectly who wins the big game, or on what day a war began, and you may be quite wrong. The past is no more immutable than the present; of course not, it is the present while you’re living in it. What we’re doing now is history to other people. Life in any year is reality, and people can act on reality and change it.”
    The more Norlund had thought about it, the more his mind had seemed to knot in paradox. “Look here,” he’d said. “Suppose I’d gone back and—and—”
    “The usual form of the argument you are trying to formulate” (this was Dr. Harbin speaking) “concerns one who goes back in time and shoots his or her own grandparent, before his own parent is conceived. This supposedly precludes the time-traveler’s own existence, creating a paradox. There are different answers, on different levels of profundity. The answer on the practical level, the one you need, is that shooting the grandparent in early youth has no more or less effect on reality than shooting the same person in modern times—what you consider modern times. If you’re there to pull the trigger, you’ll still be there afterwards, unless the shot goes through your own body. After the shot there may be another world in which you don’t exist, but that’s hardly startling; there may be an infinity of such worlds anyway. You didn’t exist in this one, either, for most of its history.”
    Now, seated at the Monahan kitchen table with his glass of water, half-listening as Monahan argued with the big corporations, Norlund was enjoying himself. No, he wouldn’t want to live in this household, but right now as a place to visit it was fine. He could hear the radio in the front room being retuned to a different station. A half-familiar voice came at him out of memory, that of some old news commentator. Walter Winchell? Boake Carter? Gabriel Heatter? He’d forgotten their exact respective time-frames. He heard the voice mention the word Repeal.
    Mrs. Monahan, not one to let a guest remain for long content with water, came fussing toward him, coffee cups in hand. Norlund nodded wisely, and agreed with her opinion that sometimes when it was hot drinking hot coffee could actually make you feel a little cooler.
    This idea was soberly debated by the other people sitting round the table. In the background Norlund heard the sound of the radio changing again. Not simple music or talk now. Sound effects? he wondered vaguely. Maybe one of those early mystery programs.
    There were two sounds in alternation. First a short one something like eeeh , and then a long, polyphonic ahhhh , deepening toward the end and seeming to break down into its myriad voices.
    The big corporations, said Monahan, were going to own everything when the Depression was over. Jerry disagreed. Mrs. Monahan fussed. Meanwhile that radio sound kept nagging at Norlund’s attention. It went on and on, and he found himself listening to it as if it were something he ought to recognize. He even thought of making some excuse and going into the living room.
    But he was still listening from the kitchen when the voice on the radio began to speak. It began almost too quietly for Norlund to hear it from two rooms away, but it soon grew louder. It rose and fell, contorting itself as if there were obstacles that it must squeeze past or overcome.
    Norlund soon recognized that the voice was speaking German. Norlund did not understand German, but when he recognized the language, a light dawned.
    He felt a chill that had nothing to do with the possible effects of hot coffee.
    He sat there, staring unseeingly at the coffee cup in front of him,