Clarence Rimbro had no objections to living in the only house on an uninhabited planet, any more than had any other of Earth's even trillion of inhabitants.

If someone had questioned him concerning possible objections, he would undoubtedly have stared blankly at the questioner. His house was much larger than any house could possibly be on Earth proper and much more modern. It had its independent air supply and water supply, ample food in its freezing compartments. It was isolated from the lifeless planet on which it was located by a force field, but the rooms were built about a five-acre farm (under glass, of course), which, in the planet's beneficent sunlight, grew flowers for pleasure and vegetables for health. It even supported a few chickens. It gave Mrs. Rimbro something to do with herself afternoons, and a place for the two little Rimbros to play when they were tired of indoors.

Furthermore, if one wanted to be on Earth proper; if one insisted on it; if one had to have people around and air one could breathe in the open or water to swim in, one had only to go out of the front door of the house.

So where was the difficulty?

Remember, too, that on the lifeless planet on which the Rimbro house was located there was complete silence except for the occasional monotonous effects of wind and rain. There was absolute privacy and the feeling of absolute ownership of two hundred million square miles of planetary surface.

Clarence Rimbro appreciated all that in his distant way. He was an accountant, skilled in handling very advanced computer models, precise in his manners and clothing, not much given to smiling beneath his thin, well-kept mustache and properly aware of his own worth. When he drove from work toward home, he passed the occasional dwelling place on Earth proper and he never ceased to stare at them with a certain smugness.

Well, either for business reasons or mental perversion, some people simply had to live on Earth proper. It was too bad for them. After all, Earth proper's soil had to supply the minerals and basic food supply for all the trillion of inhabitants (in fifty years, it would be two trillion) and space was at a premium. Houses on Earth proper just couldn't be any bigger than that, and people who had to live in them had to adjust to the fact.

Even the process of entering his house had its mild pleasantness. He would enter the community twist place to which he was assigned (it looked, as did all such, like a rather stumpy obelisk), and there he would invariably find others waiting to use it. Still more would arrive before he reached the head of the line. It was a sociable time.

"How's your planet?" "How's yours?" The usual small talk. Sometimes someone would be having trouble. Machinery breakdowns or serious weather that would alter the terrain unfavorably. Not often.

But it passed the time. Then Rimbro would be at the head of the line; he would put his key into the slot; the proper combination would be punched; and he would be twisted into a new probability pattern; his own particular probability pattern; the one assigned to him when he married and became a producing citizen; a probability pattern in which life had never developed on Earth. And twisting to this particular lifeless Earth, he would walk into his own foyer.

Just like that.

He never worried about being in another probability. Why should he? He never gave it any thought. There were an infinite number of possible Earths. Each existed in its own niche; its own probability pattern. Since on a planet such as Earth there was, according to calculation, about a fifty-fifty chance of life's developing, half of all the possible Earths (still infinite, since half of infinity was infinity) possessed life, and half (still infinite) did not. And living on about three hundred billion of the unoccupied Earths were three hundred billion families, each with its own beautiful house, powered by the sun of that probability, and each securely at peace. The number of Earths so occupied grew by millions each day.

And then one day, Rimbro came home and Sandra (his wife) said to him, as he entered, "There's been the most peculiar noise."

Rimbro's eyebrows shot up and he looked closely at his wife. Except for a certain restlessness of her thin hands and a pale look about the corners of her tight mouth, she looked normal.

Rimbro said, still holding his topcoat halfway toward the servette that waited patiently for it, "Noise? What noise? I don't hear anything."

"It's stopped now," Sandra said. "Really, it was like a deep thumping or rumble. You'd hear it a bit. Then it would stop. Then you'd hear it a bit and so on. I've never heard anything like it."

Rimbro surrendered his coat. "But that's quite impossible."

"I heard it."

"I'll look over the machinery," he mumbled. "Something may be wrong."

Nothing was, that his accountant's eyes could discover, and, with a shrug, he went to supper. He listened to the servettes hum busily about their different chores, watched one sweep up the plates and cutlery for disposal and recovery, then said, pursing his lips, "Maybe one of the servettes is out of order. I'll check them."

"It wasn't anything like that, Clarence."

Rimbro went to bed, without further concern over the matter, and wakened with his wife's hand clutching his shoulder. His hand went automatically to the contact patch that set the walls glowing. "What's the matter? What time is it?"

She shook her head. "Listen! Listen!"

Good Lord, thought Rimbro, there is a noise. A definite rumbling. It came and went.

"Earthquake?" he whispered. It did happen, of course, though, with all the planet to choose from, they could generally count on having avoided the faulted areas.

"All day long?" asked Sandra fretfully. "I think it's something else." And then she voiced the secret terror of every nervous householder. "I think there's someone on the planet with us. This Earth is inhabited."

Rimbro did the logical things. When morning came, he took his wife and children to his wife's mother. He himself took a day off and hurried to the Sector's Housing Bureau.

He was quite annoyed at all his.

Bill Ching of the Housing Bureau was short, jovial and proud of his part Mongolian ancestry. He thought probability patterns had solved every last one of humanity's problems. Alec Mishnoff, also of the Housing Bureau, thought probability patterns were a snare into which humanity had been hopelessly tempted. He had originally majored in archeology and had studied a variety of antiquarian subjects with which his delicately poised head was still crammed. His face managed to look sensitive despite overbearing eyebrows, and he lived with a pet notion that so far he had dared tell no one, though preoccupation with it had driven him out of archeology and into housing.

Ching was fond of saying, "The hell with Malthus!" It was almost a verbal trademark of his. "The hell with Malthus. We can't possibly overpopulate now. However frequently we double and redouble, Homo sapiens remains finite in number, and the uninhabited Earths remain infinite. And we don't have to put one house on each planet. We can put a hundred, a thousand, a million. Plenty of room and plenty of power from each probability sun."

"More than one on a planet?" said Mishnoff sourly.

Ching knew exactly what he meant. When probability patterns had first been put to use, sole ownership of a planet had been powerful inducement for early settlers. It appealed to the snob and despot in every one. What man so poor, ran the slogan, as not to have an empire larger than Genghis Khan's? To introduce multiple settling now would outrage everyone.

Ching said, with a shrug, "All right, it would take psychological preparation. So what? That's what it took to start the whole deal in the first place."

"And food?" asked Mishnoff.

"You know we're putting hydroponic works and yeast plants in other probability patterns. And if we had to, we could cultivate their soil."

"Wearing space suits and importing oxygen."

"We could reduce carbon dioxide for oxygen till the plants got going and they'd do the job after that."

"Given a million years."

"Mishnoff, the trouble with you," Ching said, "is you read too many ancient history books. You're an obstructionist."

But Ching was too good-natured really to mean that, and Mishnoff continued to read books and to worry. Mishnoff longed for the day he could get up the courage necessary to see the Head of the Section and put right out in plain view-bang, like that-exactly what it was that was troubling him.

But now, a Mr. Clarence Rimbro faced them, perspiring slightly and toweringly angry at the fact that it had taken him the better part of two days to reach this far into the Bureau.

He reached his exposition's climax by saying, "And I say the planet is inhabited and I don't propose to stand for it."

Having listened to his story in full, Ching tried the soothing approach. He said, "Noise like that is probably just some natural phenomenon."

"What kind of natural phenomenon?" demanded Rimbro. "I want an investigation. If it's a natural phenomenon, I want to know what kind. I say the place is inhabited. It has life on it, by Heaven, and I'm not paying rent on a planet to share it. And with dinosaurs, from the sound of it."

"Come, Mr. Rimbro, how long have you lived on your Earth?"

"Fifteen and a half years."

"And has there ever been any evidence of life?"

"There is now, and, as a citizen with a production record classified as A-I, I demand an investigation."

"Of course we'll investigate, sir, but we just want to assure you now that everything is all right. Do you realize how carefully we select our probability patterns?"

"I'm an accountant. I have a pretty good idea," said Rimbro at once.

"Then surely you know our computers cannot fail us. They never pick a probability which has been picked before. They can't possibly. And they're geared to select only probability patterns in which Earth has a carbon dioxide atmosphere, one in which plant life, and therefore animal life, has never developed. Because if plants had evolved, the carbon dioxide would have been reduced to oxygen. Do you understand?"

"I understand it all very well and I'm not here for lectures," said Rimbro. "I want an investigation out of you and nothing else. It is quite humiliating to think I may be sharing my world, my own world, with something or other, and I don't propose to endure it."