It sounded barmy to Stirling, but then, he'd barely squeaked past subjects like tensor calculus and non-Euclidian geometry, never mind quantum relativity.

"What we've done here," Mylonas nodded toward the distant research lab, "is the elementary work of understanding how fractural physical laws operate. And what we've discovered is both infinite futures and infinite pasts, all coexisting in fractured planes, sliding over and past and through one another, a bit like a child's kaleidoscope, where the patterns and colors shift as the colored pebbles tumble about. Fractural physics provides the only scientific explanation of psychic phenomena, in fact. The human mind has billions of neural connections hardwired into the nervous system and the senses. We haven't manufactured an instrument, yet, of that complexity.

"I rather fancy that precognition occurs when an individual with particularly acute senses encounters the intersection of fractural planes and is abruptly confronted by two possible futures. Two or more. There are people attuned to the future of fractural planes, just as others are attuned to a fractural plane's past. You might think in terms of one set of instruments tuned to ham radio frequencies and another tuned to microwave transmissions. People who have learned to shift their own consciousness from one plane to another—so called astral projection or out-of-body experience—are actually moving the pattern of their consciousness from one plane to another, or to some other referent point on their own plane. What we've done is engineer a way to hook the conscious portion of a human mind, which is, after all, merely a pattern of energy which can be codified and transferred from one point to another, through the endless shifting of fractural planes—"

"Wait, slow down!" Stirling resisted the temptation to massage aching temples.

Mylonas halted, brows climbing into his receding hairline. "What don't you understand? It's perfectly simple, at least in concept. It's the engineering that's a bit tricky."

"May be simple to you," Stirling muttered, "but it's perfectly impossible from where I sit. Look, perhaps I'll grant you that bit about consciousness being a shifting energy pattern. I've seen some pretty odd things, ran across a fellow once who swore on stacks of holy treatises he had yearly out-of-body experiences, and he wasn't a candidate for the loony bin, either. So maybe, for the sake of argument, I'll buy your story about projecting someone's consciousness somewhere else. But somewhen else? I'm not a credulous fool!"

"Neither am I," Mylonas said very quietly. Stirling was struck again by the depth of fright in those dark eyes.

"Suppose you explain it again. Pretend I'm a newspaper reporter or some chap on the dole, with no more science education than, say, that keg of ale can lay claim to. On second thought, perhaps you'd better leave off telling me why it works and just try explaining why it could prove dangerous in a terrorist's hands?" He had to fight the impulse to glance at Brenna McEgan.

"They might well be interested," Mylonas said patiently, "because of the potential for change, which is inherent in the shifting of the fractural planes. Changing a variable, even a minor one, could have drastic consequences. I have tried to warn Dr. Beckett against rushing blindly ahead, before proper precautions can be taken, but he won't be stopped. Not by anything short of dying, anyway. Who do you think requested help from the Home Secretary? It was not Dr. Terrance Beckett. God help us, if terrorists ever get hold of this work."

The level of tension at the crowded table rose abruptly, like a nasty miasma over a swamp, compounded of equal parts suspicion, fear, and anger. More than one set of eyes flicked uncertainly toward Brenna McEgan. She sat cool as a queen at her corner of the table, sapphire eyes focused on a speck of dust that floated somewhere over the center of the untidy tabletop. When nobody broke the awkward silence, Stirling cleared his throat.

"Surely there's no way to actually change anything in the past? It's already happened, with no way to undo it. And even if you could, wouldn't paradox destroy any possibility of changing things, stop you before you got started?"

Mylonas shook his head. "You're forgetting the infinite pasts part of the equation. If you projected the energy pattern of your consciousness into a past—say, the court of Henry II, as Dr. Beckett did, or even further back, to the time of King Arthur—"

Cedric Banning snorted into his pint of bitters without quite laughing out loud. One of the graduate students dug her elbow into his ribs. As Mylonas reddened, Indrani Bhaskar put in mildly, "There is a great deal of evidence to suggest that King Arthur was quite genuine. Not a king, perhaps, but a real historical figure."

Stirling grinned. "Yes, Dux Bellorum, and all that. Sixth century A.D., wasn't it? Last of the great Romanized Briton Lords of Battle."

"Quite," she smiled. "I see you're a well-read man, Captain Stirling. Mind your manners, Cedric."

Banning laughed, clearly unrepentant, and lifted his glass in a mock salute.

Mylonas cleared his throat. "Yes. Well. If you project yourself into a past, along the fractural plane that resonates most closely with your present, you then find yourself in a new present, with an infinite number of potential futures stretching out before you. Should you take an action contrary to the ones taken on your plane of origin, call it Fractural Prime, then your consciousness will slide into a different fractural resonance, perhaps close to your Prime, perhaps not, depending upon the magnitude of difference between the two."

"Then it isn't changing history at all, is it?" Stirling's mind had filled with images of vast sheets of multihued crystal fragmenting and crashing into one another, until the universe resembled a pile of shattered quartz, pulverized under a geologist's hammer. The longer he thought about it, the more the image disturbed him.

Mylonas sighed. "It's a bit of both actually. It isn't as simple as you imagine."

"What do you mean by that? Either it is or it isn't."

"Not in fractural physics. The key word is resonance. If you switch from one fractural plane to another, the law of conservation of energy—among other things—requires a transfer of resonant energy between them. If the two resonances are sufficiently dissimilar, a dissonance is created. An energy embolism, if you will. Depending on how far back the dissonance occurs, it may have either negligible or very serious consequences in your Fractural Prime. The resulting embolism may produce a minor bruise, or it could produce catastrophic damage."

"Catastrophic?" Stirling blinked. "What, exactly, are we talking about here? What scale? Do you mean the traveler's energy pattern is violently disrupted? As in, fatally? Or do you mean something else? Something... worse?"

"That," Mylonas said tiredly, "is precisely what we do not know. The traveler could die, yes. Maybe. Unless the dissonance only affects things after the energy pattern's shift between planes. You might be spared, while everything else fractures around you. If the dissonance is set up in the new fractural plane, you might destroy the future of that plane, rewrite it, so to speak. You'd start with a clean slate, from your perspective, although you might well be killing off billions of people in the secondary plane's future. No way to tell, of course, subjectively, from the traveler's viewpoint.

"But suppose the dissonance affects the old fractural plane, the Prime you originally came from. This one." Mylonas rapped bony knuckles against the tabletop. "What do you have, then? Your action in moving from Fractural Prime to Fractural Secondary destroys both the present and the future of your plane of origin. Shatters it to bits, in fact. By setting up the dissonant energy pattern in the past of one fractural plane, you utterly destroy at least one future, possibly both. Not a terribly attractive situation for scholars, but frightfully attractive to some madman bent on vengeance. Or a terrorist bent on political blackmail."