A Bridge of Years (35 page)

"Like
stepping stones," Archer supplied.

"Essentially."

"But
recruited for what?"

"Primarily,
as a caretaker. To live in this house. To maintain it and
protect it."

"Why?"
Catherine asked, but he imagined she had already surmised the answer.

"Because
this house is a sort of time machine."

"So
you're not a real time traveler," Archer said. "I mean, you
come from the future . . . but you're only a kind of employee."

"I
suppose that's a good enough description." "The machine in
this building isn't working the way it's supposed to—am I right?"
He nodded.

"But
if it was, and you were the custodian, who would come through here?
Who are the
real
time
travelers?"

This
was a more serious question, more difficult to answer. "Most of
the time, Doug, no one would come through. It's not a busy place.
Mainly, I collect contemporary documents —books, newspapers,
magazines—and pass them on."

"To
whom?" Catherine asked.

"People
from a time very distant from my own. They look human, but they
aren't entirely. They created the tunnels— the time machines."

He
wondered how much sense they would make of this. The
real
time
travelers,' Archer had said: as good a description as any. Ben
always trembled a little on the occasions when he was required to
interact with these beings. They were kindly and only somewhat aloof;
but one remained conscious of the evolutionary gulf. "Please
understand, much of this is as far beyond my comprehension as it may
be beyond yours. All I really know are legends, passed down by people
like myself—other custodians, other caretakers. Legends of the
future, you might say."

"Tell
us some," Archer said.

What
this concerns (Ben explained) is life on earth.

Look
at it in the context of geologic time.

In
the primeval solar system the earth is fused into coherent shape
by the collisions of orbiting planetesimals. It has a molten core, a
skin of cooler rock. It exudes gases and liquids —carbon dioxide,
water. In time, it develops an atmosphere and oceans.

Over
the course of millions of years, life of a sort arises as vermiform
crystalline structures in the porous rock of hot mineral-dense
undersea vents. In time, these crystalline structures adapt to a
cooler environment by incorporating proteins into themselves—so
successfully that the crystalline skeleton is discarded and purely
proteinoid life comes to dominate the primitive biosphere. RNA and
DNA are adopted as a genetic memory and evolution begins in earnest.

An
almost infinite diversity of structures compete against the
environment. There will never again be such complexity of life on
earth—the rest of evolution is a narrowing, a winnowing out.

The
climate changes. Prokaryotic cells poison the atmosphere with
oxygen. Continents ride tectonic plates across the magma. Life flows
and ebbs in the long intervals between cometary impacts.

Mankind
arises. It turns out that mankind, like the grasses, like the
flowering plants, is one of those species capable of transforming the
planet itself. It alters the climatic balance and might well have
drowned in its own waste products, except for an extraordinary new
ability to modify itself and to create new forms of life. These are
parallel and complementary technologies. Mankind, dying, learns
to make machines in its own image. It learns to change itself in
fundamental ways. The two capabilities combine to generate a new form
of life, self-reproducing but only marginally biological. It can be
called human because there is humanity in its lineage; it's the
legitimate heir of mankind. But it's as different from mankind as
crystalline life from the rocks it was born in, or protein life from
the rocky structures that preceded it. These new creatures are almost
infinitely adaptable; some of them live in the ocean, some of them
live in outer space. In their diaspora they occupy most of the
planets of the solar system. They are very successful. They begin to
comprehend, and eventually manipulate, some fundamental constants of
the physical universe. They visit the stars. They discover hidden
structures in the fabric of duration and distance.

Ben
paused, a little breathless. How long since these mysteries had
been explained to him? Years, he thought—no matter how you measure
it. "Catherine," he said, "would you open the window?
There's a nice breeze outside." A little dazedly, she rolled
back the blinds and lifted the window. "Thank you," Ben
said. "Very pleasant."

Archer
was frowning. "These new creatures,' these are the folks who
travel in time?"

"Who
built the machine that operates in this house, yes. You have to
understand what time travel means, in this case. They discovered what
might be called crevices in the structure of space and
time—fractures, if you like, with a shape and duration outside the
definable bounds of this universe but intersecting it at certain
points. A 'time machine' is a sort of artificial tunnel following the
contour of these crevices. In the local environment of the earth, a
time machine can only take you certain places, at certain times.
There are nodes of intersection. This house—an area surrounding it
for some hundreds of yards—is one of those nodes."

Archer
said, "Why here?"

"It's
a meaningless question. The nodes are natural features, like
mountains. There are nodes that intersect the crust of the earth
under the ocean, nodes that might open in thin air."

"How
many places like this are there, then?"

Ben
shrugged. "I was never told. They tend to cluster, both in space
and in time. The twentieth century is fairly rich in them. Not all of
them are in use, of course. And remember: they have duration as well
as location. A node might be accessible for twenty years, fifty
years, a hundred years, and then vanish."

Catherine
had been sitting in patient concentration. She said, "Let me
understand this. People a long way in the future open a pathway
to these nodes, yes?"

Ben
nodded.

"But
why? What do they use them for?" "They use them judiciously
for the purpose of historical reclamation. This century—and the
next, and my own—are the birthing time of their species. For them,
it's the obscure and distant past."

"They're
archaeologists," Catherine interpreted.

"Archaeologists
and historians. Observers. They're careful not to intervene. The
project has a duration for them, also. Time passes analogously at
both ends of the link. They're conducting a two-hundred-year-long
project to restore their knowledge of these critical centuries. When
they're finished, they mean to dismantle the tunnels. They're nervous
about the mathematics of paradox—it's a problem they don't want to
deal with."

Catherine
said, "Paradox?"

Archer
said, "A time paradox. Like if you murder your own grandfather
before you're born, do you still exist?"

She
regarded him with some astonishment. "How do you know that?"

"I
used to read a lot of science fiction."

Ben
said, "I'm told there are tentative models. The problem
isn't as overwhelming as it seems. But no one is anxious to put it to
the test."

Archer
said, "Even the presence of somebody from the future might have
an effect. Even if they just crush a plant or step on a bug—"

Ben
smiled. "The phenomenon isn't unique to time travel. In
meteorology it's called 'sensitive dependence on original
conditions.' The atmosphere is chaotic; a small event in one place
might generate a large effect in another. Wave your hand in China and
a storm might brew up in the Atlantic. Similarly, crush an aphid in
1880 and you might alter the presidential election of 1996. The
analogy is good, Doug, but the connection isn't precisely causal.
There are stable features in the atmosphere that tend to recur,
no matter what—"

"Attractors,"
Archer supplied.

Ben
was pleased. "You keep up with contemporary math?"

Archer
grinned. "I try."

"I've
been told there are similar structures in historical time—they tend
to persist. But yes, the possibility for change exists. It's an
observer phenomenon. The rule is that the present is always the
present. The past is always fixed and immutable, the future is always
indeterminate—no matter
where
you
stand."

"From
here," Archer said, "the year 1988 is unchangeable"

"Because
it's the past."

"But
if I traveled three years back—"

"It
would be the future, therefore unpredictable."

"But
there's your paradox already," Archer said. "It doesn't
make sense."

Ben
nodded. He had struggled with this idea himself . . . then submitted
to it, a Zen paradox which happened to be true and therefore
inarguable. "It's the way time works," he said. "If it
doesn't make sense, it's because you haven't made sense of it."

"You
said there was a math for this?"

"So
I'm told."

"You
don't know it?"

"It's
not twenty-second-century math. It's several millennia beyond
that. I doubt you or I could contain it without a certain amount of
neural augmentation."

Catherine
said, "This is awfully abstract."

Archer
nodded and seemed to struggle a moment with his thoughts.

Ben
looked out the window. There was something wonderfully calming
about all these Douglas firs. The sound they made when the wind moved
through them.

Archer
cleared his throat. "There's another obvious question."

The
painful question.
"You
want to know what went wrong."

Archer
nodded.

Ben
sighed and took a breath. He didn't relish these memories.

He
had reconstructed this from his own experience, from the fragmentary
memories of the cybernetics, from the evidence of the tunnel itself.

There
was a house like this house, he told Archer and Catherine, a temporal
depot, in the latter half of the twenty-first century, in Florida—in
those days a landscape of fierce tropical storms and civil war.

The
custodian of that house was a woman named Ann Heath.

(Ann,
he thought, I'm sorry this had to happen. You were kind when you
recruited me and I never had a chance to repay that kindness. Time
may be traversed but never mastered: the unexpected happens and
in the long run we are all mortal.)

The
Florida house had been scheduled for shutdown. Its environment was
growing too unpredictable. But something unexpected happened prior to
that closing. As nearly as Ben could deduce from the available clues,
the house had been invaded by forces of the American government.

The
house had possessed some defenses and so did Ann Heath, but perhaps
these had been partially dismantled prior to shutdown; in any case,
the soldiers of the grim last decades of that century were formidable
indeed, with weapons and armor rooted deep into their bodies and
nervous systems.

One
of these men must have occupied the house, overpowered Ann, and
forced her to reveal some of the secrets of the tunnel. The man had
used this information to escape into the past.

(She
must he dead,
Ben
thought.
They
must have killed her.)
The
marauder had invaded Ben's domain without warning, disabled the
cybernetics with an electromagnetic pulse, destroyed much of
Ben's body, and dumped his corpse in the woodshed. The attack had
been quick and successful.

Then
the marauder had opened a tunnel some thirty years long, to a nodal
point in New York City, where he had committed the same sort of
attack but more thoroughly; another custodian and all his cybernetics
were irretrievably destroyed.