— SLAVES
YOU GO, by E. C. Tubb
Herman came into the office beating his hands together and shivering with cold.
“Women!” he said. “Five gallons, a pint of oil and would I check the tires and battery.” He snorted. “Tires I don’t mind, but couldn’t she have left the battery until daylight?”
“Service,” said Onslow. “Service with a smile. Tip?”
“Not on your life.” Herman held out his hands to the warmth of the stove. Together with Onslow, he formed the night staff of the Acme Garage. It was a pleasant enough job, with little to do in the small hours but sit in the office and wait for some stranded motorist to call for help or service the few cars traveling through the night. He nodded toward the paper Onslow was holding.
“Anything interesting?”
“Not much. A couple of holdups, a murder and some more disappearances.” Onslow riffled the paper, his thin face adorned with heavy spectacles intent as he read the column. “You ever think about that?”
“Holdups?” Warmed, Herman sat down and lit a cigarette. Physically, he was totally opposite Onslow, being big and florid where the other man was thin and pale. He gestured with his cigarette. “Places like this don’t get held up, not with the two of us. Those punks pick single-man stations to knock over.”
“Not holdups,” said Onslow. “Disappearances.” He folded the paper and leaned forward. “Did you know that every year 12,000 people vanish? I don’t mean they run away from their families or skip their jobs. They literally vanish.” He snapped his fingers. “Just like that.”
“Must have a reason,” Herman said comfortably. He wasn’t much of a reader and was tired of the radio, so an argument with Onslow was as good a way to pass the time as any he could think of. Made something interesting to tell Mary over breakfast, too.
“No reason,” said Onslow. “No reason at all.”
Onslow warmed to his subject. “You wouldn’t think it possible in this civilization, what with social security, the police, the paperwork checking and registering of every individual, but it does. Men and women vanish and are never found again. It’s the truth.”
“I don’t doubt it,” chuckled Herman. “There have been times when I’ve felt like taking a long, one-way walk. Means nothing.”
“You don’t get it,” said Onslow. “I’m not talking about the people who have obviously decided to run away. People like that pack a bag, draw out their money from the bank, make some preparations before leaving. Most of them are easily found; all of them could be if anyone were interested enough. I’m talking about the mysteries, the people who vanish for no reason and without making any plans at all.” He shook his head. “Sometimes it worries me.”
“Maybe they were snapped up by something in a flying saucer?” Herman chuckled again; somehow, he couldn’t take Onslow’s statement seriously. He didn’t disbelieve it, for the thin man never lied, but he just couldn’t accept it He changedthe subject. “I’ve been thinking about what you told me last night. You know, that time-travel thing.”
“The paradox?” Onslow smiled. “Did you work it out?”
“I think so.” Herman frowned to stir up his memory; he and Mary had spent a couple of hours on the problem before he hit the sack. “If a man invents a time machine,” he said carefully, “and then goes back to kill his grandfather when a boy, then he couldn’t have been born, could he?”
“Hardly.”
“Then if he hadn’t been born, he couldn’t invent a time machine in the first place. But if he hadn’t invented it, he couldn’t have killed his grandfather, so he would have been born anyway.” Herman drew a deep breath. “So he didn’t kill his grandfather at all. Right?” He looked anxiously at the other man.
“Near enough.” Onslow knew better than to labor the point. “If he was born, then his grandfather couldn’t have been killed when a boy, so all that about going back and killing the old man doesn’t really enter into it.”
“That’s what I said,” lied Herman. “Mary kept trying to tie me in knots, but I made her see sense in the end.” He hesitated. “Got any more?”
“Paradoxes?” Onslow looked surprised. “Sure, if you’re interested.”
“I’m interested.” Herman glanced through the office windows. The night was a bad one, cold, wet, miserable, a night most people would choose to stay indoors. “May as well talk as read or listen to the radio. More interesting anyway.”
“How about this one?” Onslow helped himself to a cigarette and hunched closer to the stove. “An old Greek named Zeno dreamed it up and it’s a good one. Achilles was going to race a tortoise. The tortoise was placed halfway down a measured strip — it doesn’t matter how long — and Achilles stood at the starting line. You get the idea?”
“Sure, the tortoise was given a big start.”
“It was halfway down the strip,” said Onslow. “So the race started. Now before Achilles could catch up with the tortoise, he had to cover half the distance between them. Right?”
Herman frowned, then nodded. “Sure, of course. He had to reach the halfway mark between them.”
“Yes, but by the time he had reached that halfway mark the tortoise had moved on a bit further. So Achilles had to cover half that distance, by which time the tortoise had moved on still more. So Achilles had to cover half that distance and then half the next distance and so on.” Onslow leaned back. “How did Achilles ever catch up with the tortoise?”
“Uh?” Herman looked blank. “By running faster, of course. Nothing to it.”
“Isn’t there?” Onslow reached for paper and pencil. “Look at it this way.” He made swift sketches. “First he had to cover half the first distance, then half the second, then the third and all the rest. Look at it that way and he could never have caught up, because, no matter how short the distance, he had always to cover a half of it, by which time the tortoise had moved on.”
“I see,” said Herman glumly. This was one time when he couldn’t dazzle Mary with his superior knowledge. It wasn’t much good taking home a problem to which he didn’t know the answer.
Onslow took pity on him. “No one can really work it out the way it’s stated. They say that calculus can do it, but I wouldn’t know. The easy answer is that Achilles wasn’t racing to catch up with the tortoise at all; he was running to a point past the finishing line. That way, all he had to do was cover a series of decreasing halves of distance and so, naturally, he won hands down.”
“Sure,” said Herman, relieved. “The gimmick depends on which way you look at it.”
He glanced at his watch, then through the windows. A car came down the road, slowed and swung into the forecourt of the all-night restaurant a few hundred feet lower down. Onslow, who had headed toward the door when he heard the slowing car, grunted and busied himself at the stove instead.
Herman switched on the radio, listened to a disc jockey announcing the next record, then switched off with a grunt of disgust. “Got any more?”
“Paradoxes?” Onslow looked thoughtful. “Have you heard the one about the missing unit?”
“Tell me,” Herman invited.
“Three men go into a restaurant,” said Onslow. “The bill comes to thirty units and—”
“Units?”
“Dollars, pounds, rupees, it doesn’t matter what you call them.” Onslow lit a fresh cigarette. “The bill comes to thirty units — dollars, say. The manager, after the bill has been paid, finds that he’s overcharged by five dollars. He gives the five dollars to a waiter who, being dishonest, gives each of the three men one dollar each and pockets the two remaining.” Onslow flicked his cigarette. “Now, in effect, the men have each paid nine dollars for their meal. Three nines are twenty-seven. The waiter has kept two dollars. Twenty-seven and two make twenty-nine. Where is the other dollar?”