"But then I'd exist without—without an origin!" she protested. "I'd have life, and memories, and . . . everything . . . though nothing had produced them."
Kelm shrugged. "What of it? You insist that the causal law, or strictly speaking the conversation-of-energy law, involve only continuous functions. Actually, discontinuity is entirely possible."
He laughed and leaned on the lectern. "Of course, there are impossibilities," he said. "You could not be your own mother, for instance, because of sheer genetics. If you went back and married your former father, the children would be different, none of them you, because each would have only half your chromosomes."
Clearing his throat: "Let's not stray from the subject. You'll learn the details in other classes. I'm only giving you a general background. To continue: the Nine saw the possibility of going back in time and preventing their enemies from ever having gotten started, even from ever being born. But then the Danellians appeared."
For the first time, his casual, half-humorous air dropped, and he stood there as a man in the presence of the unknowable. He spoke quietly: "The Danellians are part of the future—our future, more than a million years ahead of me. Man has evolved into something . . . impossible to describe. You'll probably never meet a Danellian. If you ever should, it will be . . . rather a shock. They aren't malignant—nor benevolent—they are as far beyond anything we can know or feel as we are beyond those insectivores who are going to be our ancestors. It isn't good to meet that sort of thing face to face.
"They were simply concerned with protecting their own existence. Time travel was old when they emerged, there had been uncountable opportunities for the foolish and the greedy and the mad to go back and turn history inside out. They did not wish to forbid the travel—it was part of the complex which had led to them—but they had to regulate it. The Nine were prevented from carrying out their schemes. And the Patrol was set up to police the time lanes.
"Your work will be mostly within your own eras, unless you graduate to unattached status. You will live, on the whole, ordinary lives, family and friends as usual; the secret part of those lives will have the satisfactions of good pay, protection, occasional vacations in some very interesting places, supremely worthwhile work. But you will always be on call. Sometimes you will help time travelers who have gotten into difficulties, one way or another. Sometimes you will work on missions, the apprehension of would-be political or military or economic conquistadors. Sometimes the Patrol will accept damage as done, and work instead to set up counteracting influences in later periods which will swing history back to the desired track.
"I wish all of you luck."
* * *
The first part of instruction was physical and psychological. Everard had never realized how his own life had crippled him, in body and mind; he was only half the man he could be. It came hard, but in the end it was a joy to feel the utterly controlled power of muscles, the emotions which had grown deeper for being disciplined, the swiftness and precision of conscious thought.
Somewhere along the line he was thoroughly conditioned against revealing anything about the Patrol, even hinting at its existence, to any unauthorized person. It was simply impossible for him to do so, under any influence; as impossible as jumping to the moon. He also learned the ins and outs of his twentieth-century public persona.
Temporal, the artificial language with which Patrolmen from all ages could communicate without being understood by strangers, was a miracle of logically organized expressiveness.
He thought he knew something about combat, but he had to learn the tricks and the weapons of fifty thousand years, all the way from a Bronze Age rapier to a cyclic blast which could annihilate a continent. Returned to his own era, he would be given a limited arsenal, but he might be called into other periods and overt anachronism was rarely permissible.
There was the study of history, science, arts and philosophies, fine details of dialect and mannerism. These last were only for the 1850-1975 period; if he had occasion to go elsewhere he would pick up special instruction from a hypnotic conditioner. It was such machines that made it possible to complete his training in three months.
He learned the organization of the Patrol. Up "ahead" lay the mystery which was Danellian civilization, but there was little direct contact with it. The Patrol was set up in semimilitary fashion, with ranks, though without special formalities. History was divided into milieus, with a head office located in a major city for a selected twenty-year period (disguised by some ostensible activity such as commerce) and various branch offices. For his time, there were three milieus: the Western world, headquarters in London; Russia, in Moscow; Asia, in Peiping; each in the easygoing years 1890-1910, when concealment was less difficult than in later decades, when there were smaller offices such as Gordon's. An ordinary attached agent lived as usual in his own time, often with an authentic job. Communication between years was by tiny robot shuttles or by courier, with automatic shunts to keep such messages from piling up at one instant.
The entire organization was so vast that he could not really appreciate the fact. He had entered something new and exciting, that was all he truly grasped with all layers of consciousness . . . as yet.
He found his instructors friendly, ready to gab. The grizzled veteran who taught him to handle spaceships had fought in the Martian war of 3890. "You boys catch on fairly quick," he said. "It's hell, though, teaching pre-industrial people. We've quit even trying to give them more than the rudiments. Had a Roman here once—Caesar's time—fairly bright boy, too, but he never got it through his head that a machine can't be treated like a horse. As for the Babylonians, time travel just wasn't in their world-picture. We had to give them a battle-of-the-gods routine."
"What routine are you giving us?" asked Whitcomb.
The spaceman regarded him narrowly. "The truth," he said at last. "As much of it as you can take."
"How did you get into this job?"
"Oh . . . I was shot up off Jupiter. Not much left of me. They picked me up, built me a new body—since none of my people were alive, and I was presumed dead, there didn't seem much point in going back home. No fun living under the Guidance Corps. So I took this position here. Good company, easy living, and furloughs in a lot of eras." The spaceman grinned. "Wait till you've been to the decadent stage of the Third Matriarchy! You don't know what fun is."
Everard said nothing. He was too captured by the spectacle of Earth, rolling enormous against the stars.
He made friends with his fellow cadets. They were a congenial bunch—naturally, with the same type being picked for Patrollers, bold and intelligent minds. There were a couple of romances. No Portrait of Jenny stuff; marriage was entirely possible, with the couple picking some year in which to set up housekeeping. He himself liked the girls, but kept his head.
Oddly, it was the silent and morose Whitcomb with whom he struck up the closest friendship. There was something appealing about the Englishman; he was so cultured, such a thoroughly good fellow, and still somehow lost.
They were out riding one day, on horses whose remote ancestors scampered before their gigantic descendants. Everard had a rifle, in the hope of bagging a shovel-tusker he had seen. Both wore Academy uniform, light grays which were cool and silky under the hot yellow sun.
"I wonder we're allowed to hunt," remarked the American. "Suppose I shoot a sabertooth—in Asia, I suppose—which was originally slated to eat one of those prehuman insectivores. Won't that change the whole future?"
"No," said Whitcomb. He had progressed faster in studying the theory of time travel. "You see, it's rather as if the continuum were a mesh of tough rubber bands. It isn't easy to distort it; the tendency is always for it to snap back to its, uh, 'former' shape. One individual insectivore doesn't matter, it's the total genetic pool of their species which led to man.