For King & Country by Robert Asprin, Linda Evans, James Baen

all combining like the clattering of an unseen train roaring past in the fog. An ominous tremor began in the pit of his stomach, worse than pre-combat jitters. Stirling unfroze long enough to completely drain his glass in one long gulp, before gesturing for another. "All right," he finally managed. "Give me a lesson in time travel, professor."
    "We'll begin with the basic physics of the project," Mylonas leaned forward, rolling his own empty bar glass between his hands. "You understand, surely, the concept of infinite potential futures? If I do
x
instead of
y
and you respond with
b
instead of
c
and so on, multiplied by all the physical factors in the universe? A crushed butterfly that robs some bird of its dinner, which prevents the offspring from transmitting a fatal disease that would have wiped out half of Asia. Or a supernova or meteorite being taken as a sign from God, prompting someone to invade a neighbor, abandon a revolution, or engineer a new religion which in turn kills several million people under the guise of saving their souls. If one accepts this as fact—or, perhaps I should say, as unchallenged hypothesis, as we are all scientists laboring under the scientific theory—then one must also understand there are an infinite number of potential
pasts,
as well. I didn't do
x
, but did
y
instead, you didn't respond with
b
, but rather did
c
."
    "Well, I suppose so," Stirling frowned, "but look here, this doesn't make logical sense. How can
both
x
and
y
have happened, when clearly, only
x
did
happen?"
    "It's a matter of quantum physics," Mylonas said patiently, "or rather, a matter of
fractural
physics, which is not something even your average quantum physicist has begun to grasp."
    "
Fractural
physics?" Stirling echoed. "What the devil is that?"
    "A bloody Nobel Prize," Cedric Banning grinned, raising his half-drained glass in a salute.
    Mylonas shot Banning a quelling glance. "Quite.
If
the Home Office will ever allow us to publish our data." The haunted look in the man's eyes deepened. Stirling narrowed his gaze, realizing abruptly that Mylonas
wanted
the Home Office to keep his work classified. Oddly, none of the others appeared to be so deeply rattled. Rampant delight was the operative word at this table. What did Mylonas know, that the others hadn't glimpsed, yet?
    "Go on, please," Stirling said quietly, sipping from his second glass of stout. "What
is
fractural physics?"
    "A mathematical way of describing, of accounting for, the impossibilities in observation which neither quantum physics nor its mathematical system can explain. Surely you knew, already, that the simple act of observation literally brings a thing into being, at the quantum level? Observation equals creation. If you ask the right question, in other words, the universe obliges you by providing a previously nonexistent answer. And if a thing exists, it can be fractured into something else; time is no exception. In fact, without fractural physics, nothing would—or could—exist."
    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