“If we admit among the universes of probability any in which the laws of physical reality are different from our own, we will have an infinite number of universes. If we restrict ourselves to the laws of physical reality as we know them, we will have a limited number. Our universe is quantized; therefore the differences between possible universes (although very small) must be similarly quantized, and the number of such universes must be finite (although very large). I take it that it must be possible to distinguish the very smallest differences—say, that of one quantum of light—for otherwise we could not find our way to the same universe time after time, nor could we return to our own. Current theory has it that one cannot return to one’s own past, but only to other people’s; similarly one cannot travel into one’s own future, but only to other people’s, and in no way can these motions be forced to result in straightforward travel—from any baseline whatever . The only possible motion is diagonal motion. So you see that the classical paradoxes of time-travel simply do not apply—we cannot kill our own grandmothers and thereby cease to exist, nor can we travel into our own future and affect it in advance, so to speak. Nor can I, once I have made contact with your present, travel into your past or your future. The best I can do in finding out my own future is to study one very close to my own, but here the cost of power becomes prohibitive. My Department’s researches are therefore conducted in regions rather far from home. Go too far and you find an Earth too close to the sun or too far away or nonexistent or barren of life; come too close and it costs too much. We operate in a pretty small optimal range. And of course I was doing this on my own, which means I must steal the whole damn operation anyway.
“You, Janet, were almost impossible to find. The universe in which your Earth exists does not even register on our instruments; neither do those for quite a probable spread on either side of you; we have been trying for years to find out why. Besides you are too close to us to be economically feasible. I had located Jeannine and not Joanna; you very obligingly stepped out of place and became as visible as a sore thumb; I’ve had a fix on you ever since. The three of you got together and I pulled you all in. Look at yourselves.
“Genetic patterns sometimes repeat themselves from possible present universe to possible present universe; this is also one of the elements that can vary between universes. There is repetition of genotypes in the far future too, sometimes. Here is Janet from the far future, but not my future or yours; here are the two of you from almost the same moment of time (but not as you see it!), both of those moments only a little behind mine; yet I won’t happen in the world of either of you. We are less alike than identical twins, to be sure, but much more alike than strangers have any right to be. Look at yourselves again.
“We’re all white-skinned, eh? I bet two of you didn’t think of that. We’re all women. We are tall, within a few inches of each other. Given a reasonable variation, we are the same racial type, even the same physical type—no redheads or olive skins, hm? Don’t go by me; I’m not natural! Look in each other’s faces. What you see is essentially the same genotype, modified by age, by circumstances, by education, by diet, by learning, by God knows what. Here is Jeannine, the youngest of us all with her smooth face: tall, thin, sedentary, round-shouldered, a long-limbed body made of clay and putty; she’s always tired and probably has trouble waking up in the morning. Hm? And there’s Joanna, somewhat older, much more active, with a different gait, different mannerisms, quick and jerky, not depressed, sits with her spine like a ruler. Who’d think it was the same woman? There’s Janet, hardier than the two of you put together, with her sun-bleached hair and her muscles; she’s spent her life outdoors, a Swedish hiker and a farmhand. You begin to see? She’s older and that masks a good deal. And of course she has had all the Whileawayan improvements—no rheumatism, no sinus trouble, no allergies, no appendix, good feet, good teeth, no double joints, and so forth and so forth, all the rest that we three must suffer. And I, who could throw you all across the room, though I don’t look it. Yet we started the same. It’s possible that in biological terms Jeannine is potentially the most intelligent of us all; try to prove that to a stranger! We ought to be equally long-lived but we won’t be. We ought to be equally healthy but we’re not. If you discount the wombs that bore us, our pre-natal nourishment, and our deliveries (none of which differ essentially) we ought to have started out with the same autonomic nervous system, the same adrenals, the same hair and teeth and eyes, the same circulatory system, and the same innocence. We ought to think alike and feel alike and act alike, but of course we don’t. So plastic is humankind! Do you remember the old story of the Doppelganger? This is the double you recognize instantly, with whom you feel a mysterious kinship. An instant sympathy, that informs you at once that the other is really your very own self. The truth is that people don’t recognize themselves except in mirrors, and sometimes not even then. Between our dress, and our opinions, and our habits, and our beliefs, and our values, and our mannerisms, and our manners, and our expressions, and our ages, and our experience, even I can hardly believe that I am looking at three other myselves. No layman would entertain for a moment the notion that he beheld four versions of the same woman.
Did I say a moment? Not for an age of moments, particularly if the layman were indeed a man.
“Janet, may I ask you why you and your neighbors do not show up on our instruments? You must have discovered the theory of probability travel some time ago (in your terms), yet you are the first traveler. You wish to visit other universes of probability, yet you make it impossible for anyone to find you, let alone visit you.
“Why is that?”
“Aggressive and bellicose persons,” said Janet with care, “always assume that unaggressive and pacific persons cannot protect themselves.
“Why is that?”
VI
Over trays of pre-cooked steak and chicken that would’ve disgraced an airline (that’s where they came from, I found out later) Jael sat next to Jeannine and glued herself to Jeannine’s ear, glancing round at the rest of us from time to time to see how we were taking it. Her eyes sparkled with the gaiety of corruption, the Devil in the fable tempting the young girl. Whisper, whisper, whisper. All I could hear were the sibilants, when her tongue came between her teeth. Jeannine stared soberly ahead and didn’t eat much, the color leaving her little by little. Jael didn’t eat at all. Like a vampire she fed on Jeannine’s ear. Later she drank a sort of super-bouillon which nobody else could stand and talked a lot to all of us about the war. Finally, Janet said bluntly:
“What war?”
“Does it matter?” said Miss Reasoner ironically, raising her silver eyebrows. “This war, that war, isn’t there always one?”
“No,” said Janet.
“Well, hell,” said Jael more genuinely, “the war. If there isn’t one, there just was one, and if there wasn’t one, there soon will be one. Eh? The war between Us and Them. We’re playing it rather cool just now because it’s hard to work up an enthusiasm for something forty years old.”