by Larry Niven
"But that wasn't enough," I objected. "You'd still die."
The rammer nodded. "Still I was glad to see him go, at first. He was terrifying. And his last mistake was almost a relief. It proved that he was—human is not the word I want. But he could make mistakes."
"Mortal," I said. "He was mortal."
"I do not understand. But never mind. Think of the power of him. In a year and a half, at point six gravities, I had accelerated to a velocity which the intruder cancelled in no more than a second. I preferred death to his dreadful company. At first.
"Then I became afraid. It seemed unjust. He had found me halfway between stars, stranded, waiting to die. He had half-saved me—and then left me to die, no better off than before!
"I searched for him with the scope. Perhaps I could signal him, if I knew where to aim my com laser... . But I could not find him.
"Then I became angry. I—" The rammer swallowed. "I screamed insults after him. I blasphemed in seven different religions. The more distant he was, the less I feared him. I was reaching my stride when— when he returned.
"His face was outside my main window, his red eyes looked into mine, his strange hand was reaching for my main pod. My collision alarm was just beginning to sound, it had happened so suddenly. I screamed out— I screamed..." He stopped.
"What did you scream?"
"Prayers. I begged for forgiveness."
‘‘Oh."
"He took my ship in his hand. I saw the stars explode in front of me." We had reached the shade of a dark oak, one so old and so spread out that its lower limbs needed the support of iron pipes. A family picnicking beneath the tree watched our approach.
"Explode?"
"That lacks accuracy," the rammer apologized. "What happened was this: the stars became very much brighter, at the same time converging toward a point. They flared horribly. I was blinded. The intruder must have shifted me to within a meter-per-second of lightspeed.
"I rubbed my hand hard across my eyes. With my eyes closed, I felt acceleration. It remained constant while I waited for my eyes to recover. Through experience I was able to estimate its force at ten meters per second squared."
"But that's—"
"One gravity. When I could see again, I found myself on a yellow plain beneath a glaring blue sky. My pod was red hot, and was already sagging around me."
"Where did he put you?"
"On Earth, in a refertilized part of North Africa. My pod was never built for such things. If Earth's gravity collapsed it, then re-entry should have torn it to pieces. But the intruder must have taken care of that too."
I am a peoplewatcher, an expert. I can crawl into a man's mind without letting him know I exist. I never lose at poker. And I knew the rammer was not lying.
We stood beside the dark oak. The lowermost limb grew almost parallel to the ground, and was supported by three iron pipes. Long as were the rammer's arms, he could not have wrapped them around that limb. Its bark was rough and gray and powdery, and it smelled of dust. The top of it was level with the rammer's chin.
"You're a very lucky man," I said.
"No doubt. What is that?"
Black and furry, an inch and a half long; one end wiggling in blind curiosity as it moved along the bark.
"A caterpillar. You know, there's no computing the odds you ran against being alive now. You don't seem very cheerful about it."
"I was... but think about it," said the rammer. "Think what the intruder must have reasoned out, to do what he did.
"He looked through the main window to examine me as well as he could. I was tied to a chair by crash straps, and his sensors had to see through thick impact quartz designed for transparency in the other direction. He could see me, but only from the front. He could examine the ship, but it was damaged, and he had to guess to what extent.
"First he must have reasoned that I could not slow my ship without the ramscoop web. But he must also have deduced the presence of reserve fuel to decelerate me to zero speed from the lowest speed at which my ramscoop can operate. It is apparent that I must have it. Thus he stopped me dead, or nearly so, and left me to go home the slow way, using only my re-entry reserve fuel.
"After he had left me, he must have realized that I would be dead of age before I ended such a trip. Imagine how thorough his examination of me must have been! So he came back for me.
"By projecting my line of flight he must have known where I was going. But could I live there with a damaged ship? He did not know.
"And so he looked me over more carefully, deduced the star and planet where I must have evolved, and he put me there."
"That's pretty farfetched," I said.
"Yes! The solar system was twelve light-years distant, yet he reached it in an instant! But that is not the point... ." The rammer let his voice trail off. He seemed oddly fascinated by the black caterpillar, which was now defying gravity as it explored a vertical wall of bark. "He placed me not only on Earth, but in North Africa. He deduced not only my planet of origin, but the region where I had evolved.
"I stayed in my pod for two hours before I was found. Your United Nations police took a record of my mind, but they do not believe what they found. A ramship pod cannot be towed to Earth without radar finding it. Further, my ramscoop web is all over the desert. Even the hydrogen balloons survived the reentry. They think that it must be a hoax, that I was brainwashed as part of that hoax."
"And you? What do you think?"
Again the rammer's face tightened into jigsaw-puzzle lines. "I had convinced myself that the intruder was no more than another spacecraft pilot—a passerby who stopped to help, as some persons will stop to help if your car battery fails far from a city. His power might be greater than mine. He might be wealthier, even within the context of his own culture. We were of different species. Yet he had stopped to help a member of the great brotherhood, for we were both spacemen."
"Because your modern xenology says he couldn't have been your superior."
He didn't answer.
"I can pick a few holes in that theory."
"Can you?"
I ignored his disinterest. "You claim that evolution stops when a species starts building tools. But suppose two tool-users evolved on the same world? Then evolution might go on until one race was dead. We might have had real problems if the dolphins had had hands."
"It may be." He was still watching the caterpillar: an inch and a half of black fur exploring the dark bark. My ear brushed the bark as I faced him, and I smelled the damp wood.
"Then again, not all human beings are alike. There are Einsteins and there are morons. Your passerby might have been of a race that varies more. Make him a super-Einstein—"
"I had not thought of that. I had assumed that his deductions were made with the aid of a computer. At first."
"Then, a species could evolve itself. if they once started fiddling with their genes, they might not stop until their children were mile-high giants with a space drive stuck up their spines. What the hell is so interesting about the caterpillar?"
"You did not see what the boy did?"
"Boy? Oh. No, I didn't."
"There was a... caterpillar moving along the gravel walk. People passed. None looked down. The boy came, and he stooped to watch."
"Oh!"
"Presently the boy picked up the caterpillar, looked about him, then came here and put the caterpillar safely on the limb."
"And you fainted."
"I should not have been so affected by what, after all, is no more than a comparison. I would have cracked my skull had you not caught me."
"A poor return for the golden one, if you had."
The rammer did not smile. "Tell me... if an adult had seen the caterpillar, instead of a boy—"
"Probably he'd have stepped on it."
"Yes, I thought so." The rammer put his tongue in his cheek, which stretched incredibly. "He is nearly upside down. I hope he will not fall off."
"It won't."
; "Do you think he is safe there?"
"Sure. Don't worry about it."
FOR A FOGGY NIGHT
The bar was selling a lot of Irish coffee that night. I'd bought two myself. It was warm inside, almost too warm, except when someone pushed through the door. Then a puff of chill, damp fog would roll in.
Beyond the window was grey chaos. The fog picked up all the various city lights: yellow light leaking from inside the bar, passing automobile headlights, white light from frosted street globes, and the rainbow colors of neon signs. The fog stirred all the lights together into a cold graywhite paste and leaked it hack through the windows.
Bright spots drifted past at a pedestrian's pace. Cars. I felt sorry for the drivers. Rolling through a gray formless limbo, running from street globe to invisible street globe, alert for the abrupt, dangerous red dot of a traffic light: an intersection; you couldn't tell otherwise... I had friends in San Francisco; there were other places I could be. But it wasn't my city, and I was damned if I'd drive tonight.
A lost night. I'd finished my drink. One more, and I'd cross the street to my hotel.
"You'd best wait until the fog thins out," said the man next to me.
He was a stranger, medium all over; medium height and weight, regular features, manicured nails, feathery brown hair, no scars. The invisible man. I'd never have looked his way if he hadn't spoken. But he was smiling as if he knew me.
I said, "Sorry?"
"The point is, your hotel might not be there when you've crossed the street. Don't be surprised," he added. "I can read minds. We've learned the knack, where I come from."
There are easy ways to interrupt a conversation with a stranger. A blank stare will do it. But I was bored and alone, and a wacky conversation might be just what I needed.
I said, "Why shouldn't my hotel be exactly where I left it?"
He frowned into his scotch-and-soda, then took a swallow. "Do you know the theory of multiple world lines? It seems that whenever a decision is made, it's made both ways. The world becomes two or more worlds, one for each way the decision can go. Ah, I see you know of it. Well, sometimes the world lines merge again."
‘‘But—''
"That's exactly right. The world must split on the order of a trillion times a second. What's so unbelievable about that? If you want a real laugh, ask a physicist about furcoated particles."
"But you're saying it's real. Every time I get a haircut—"
"One of you waits until tomorrow," said the brown-haired man. "One of you keeps the sideburns. One gets a manicure, one cuts his own nails. The size of the tip varies too. Each of you is as real as the next, and each belongs to a different world line. It wouldn't matter if the world lines didn't merge every so often."
"Uh huh." I grinned at him. "What about my hotel?"
"I'll show you. Look through that window. See the street lamp?"
"Vaguely."
"You bet, vaguely. San Francisco is a town with an active history. The world lines are constantly merging. What you're looking at is the probability of a street lamp being in a particular place. Looks like a big fuzzy ball, doesn't it? That's the locus of points where a bulb might be
—or a gas flame. Greatest probability density is in the center, where it shows brightest."
"I don't get it."
"When the world lines merge, everything blurs. The further away something is, the more blurred it looks. I shouldn't say looks, because the blurring is real; it's no illusion. Can you see your hotel from here?"
I looked out the appropriate window, and I couldn't. Two hours ago I'd nearly lost my way just crossing the street. Tonight a man could lose himself in any city street, and wander blindly in circles in hopes of finding a curb. .
"You see? Your hotel's too far away. In the chaos out there, the probability of your hotel being anywhere specific is too small to see. Vanishingly small. You'd never make it."
Something about the way he talked…
"I wondered when you'd notice that." He smiled as if we shared a secret.
"All this time," I said, "I've been thinking that you talk just like everyone else. But you don't. It's not just the trace of accent. Other people don't say probability density or theorem or on the order of."
"No, they don't."
"Then we must both be mathematicians!" I smiled back at him.
"No," he said.
"But then..." But 1 backed away from the problem, or from the answer. "My glass is empty. Could you use a refill?"
"Thanks, I could."
I fixed it with the bartender. "Funny thing," I told the brown-haired man. "I always thought the blurring effect of fog came from water droplets in the air."
"Bosh," he said. "Bosh and tish. The water's there, all right, whenever the fog rolls in. I can't explain it. The condensation must be a side effect from the blurring of the world lines. But that's not interfering with your vision. Water's transparent."
"Of course. How could I have forgotten that?"
"I forgot it myself, a long time ago." The scotch was beginning to reach him, I think. He had an accent, and it was growing stronger. "That's why I'm here. That's why I stopped you. Because you'd remember."
The bartender brought us our drinks. His big shoulders were hunched inward against the damp gray light that seeped in the windows.
I sipped at the burning hot glass. Irish whiskey and strong black coffee poured warmth through me, to counteract the cold beyond the walls. A customer departed, and the fog swirled around him and swallowed him.
"I walked into the fog one afternoon," said the brown-haired man. "The fog was thick, like tonight. A cubic mile of cotton, as we say. I was just going out for a pouch of snuff. When I reached the tobacconist's he tried to sell me a bundle of brown paper sticks with a Spanish trademark."
"Uh huh. What did you do?"
"Tried to get home, of course. Things changed oddly while I wandered in the fog. When it cleared and left me stranded, even my money was no good. The worst of it was that I couldn't even tell my story. Nobody could read my mind to see that I was sane. It was find another fog bank or try to make a life for myself."
"With no money?"
"Oh, I sold my ring and found a poker game."
"Oh. Oh!"
"That was a year ago. It's worked out well enough. I thought I might invent something, like the zipper, but that fell through. You're far ahead of us in the physical sciences. But money's no problem. Sometimes there's a fixed horse race. Sometimes I find a poker game, or a crooked crap game where they'll let me bet the right way."
"Sounds great." But not very honest, I thought.
"You disapprove?" My companion's voice had gone thin and cold.
"I didn't say that."
"I compensate for what I take," the brown-haired man said angrily. "I know how to untwist a sick man's mind. If a player sits down with emotional problems, I can help him. If he really needs the money, I can see that it comes to him."
"Why don't you become a psychiatrist?"
He shook his head. "It would take years, and then I'd never be able to hold a patient long enough to do myself any good. He'd get well too fast. Besides that, I hate certain people; I'd want to harm them instead of helping them. .
"Anyway, I don't go out in the fog anymore. I like it here. I stopped you because you're one of those who remember."
"You said that before. What exactly—?"
"After all, people are constantly walking into fogs. Why is it that we don't hear more about people wandering in from alternate world lines? It's because their memories adjust."
"Ah."
"I caught it happening once. A girl from somewhere else... I didn't catch the details; they faded too fast. I got her a job as a go-go dancer. I think she was a prize concubine in someone's harem before she ran into the fog.
"Their memories adjust. They forget their friends, their relatives, their husbands and wives in the old world line. They remember what man is king or president or chairman in the new.
But not us. You and I are different. I can recognize the rare ones."
"Because you can read minds." Sarcastically. Part of me still disbelieved; yet... it fit too well. The brown-haired man talked like a mathematics professor because he was talking to me, and I was a mathematics professor, and he was reading my mind.
He looked thoughtfully into his glass. "It's funny, how many sense the truth. They won't walk or drive in the fog if they can help it. At the bottom of their minds, they know that they might return home to find a Romish camp, or a Druidic dancing ground, or the center of a city, or a sand dune. You knew it yourself. The top of your mind thinks I'm an entertaining liar. The deepest part of you knew it all before I spoke."
"I just don't like fog," I said. I looked out the window, toward my hotel, which was just across the street. I saw only wet gray chaos and a swirling motion.
"Wait until it clears."
"Maybe I will. Refill?"
"Thanks."
Somehow, I found myself doing most of the talking. The brown-haired man listened, nodded occasionally, asked questions from time to time.
We did not mention fog.
"I need an ordered universe," I said at one point. "Why else would I have studied math? There's never an ambiguity in mathematics."
"Whereas in interpersonal relationships..."
"Yes! Exactly!"
"But mathematics is a game. Abstract mathematics doesn't connect with the real universe except by coincidence or convenience. Like the imaginary number system: it's used in circuit design, but it certainly wasn't intended for that."
"No, of course not."
"So that's why you never got married?"
"Right," I said sadly. "Ordered universe. Hey, I never knew that. Did I?"
The fog cleared about one o'clock. My brown-haired friend accompanied me out.
"Mathematics doesn't fit reality," he was saying. "No more than a game of bridge. The real universe is chaotic."
"Like in-ter-personal re-lationships."
"Maybe you'll find them easier now."