The Wandering Soul

Never stop while you can still go on. That was Courage’s creed, and it had become a motto known throughout the Alliance. The ship had opened the Age of the Great Passage by discovering an invisible bridge over a sheer abyss. What had been an impassable barrier was now an open road.

Even before the discovery, Courage had been enough of a legend to appear in the Alliance’s textbooks—in physics, engineering, sociology, medicine, biology, law, history, even philosophy: almost every subject there was. Nor did any of these appearances seem out of place. Courage was one of the few truly exceptional cases in the Alliance.

Originally, Courage had been an ordinary cargo ship plying the Alliance’s planetary system between its homeworld and a moon of the fifth planet. Its pilot, Mao Feidu, was an equally ordinary graduate of a spaceflight academy. If all went well, his career would consist of three round trips between the homeworld and the base on that moon, followed by an honorable retirement. But on his first voyage, as Courage headed back from the base, a maintenance crew’s mistake left it short of fuel. Worse, the shortage was not discovered until the ship had passed the critical point for turning back. Mao Feidu and Courage were forced into a dazzling, hair-raising game of pinball through space. At an extremely shallow inclination, he barely skimmed past the asteroid belt and entered orbit around the fourth planet, using its gravity to fling the ship toward the second. Five years of drifting through space finally brought a chance to change course into orbit around the second planet. Its gravity at last sent him bouncing home.

Now Mao Feidu had time for only one more round trip in his career. Perhaps not even that: setting out again would be difficult. His long confinement in space had left his muscles severely wasted, his bones terribly brittle, and his organs on the brink of failure. It looked like the end of a rather remarkable novice pilot. It was actually where the legend of Courage began.

The doctor gave Mao Feidu two choices. He could remain in bed on life support and recuperate. If his body proved as hard to break as he was hard to kill, he might be able to get out of bed by the time his pension arrived. Or he could try the Academy of Sciences’ latest advances and be a guinea pig for an unprecedented, horrifying reconstruction. The kindly doctor recommended the first option. A hero like him would receive the best possible care and treatment, and his life could certainly be saved. Choose the second, though, and those bastards at the Academy would never let such a rare specimen slip through their hands. They would promise anything. The bastards at the Academy, for their part, asked whether he really wanted to rot in bed. They said nothing of the enormous risks that must exist; nobody could deny those anyway. Besides, Mao Feidu was not the only one taking a risk. If he died, would they not lose their specimen and damage their reputation into the bargain?

Mao Feidu had faith in his own constitution. He really did not want to rot in bed, though. Better to die. Over the next while, a little under half his organs were replaced. Assorted artificial parts filled him up, turning him into a monster in human skin. Which felt pretty cool. Somehow he survived, becoming the space marine he had dreamed of being as a boy. No, he was more impressive than a space marine: Mao Feidu had survived that murderous reconstruction with nothing but a mortal body. The Academy staff assured him that the prosthetics would last him to the end of his life, and even add a few years to it.

The Academy staff were not all talk, but the doctor had been right about them too. They really did have very little conscience. Mao Feidu enjoyed a happy year. Then, as he prepared to return to space, his body duly began to give trouble. The prosthetics had not failed. Instead, his other, healthy organs suddenly showed signs of shutting down. Whether the replacements had caused this was hard to say. This time there were no two options to choose between. The doctor could do nothing; he could only submit to further reconstruction. When that was finished, the head was the only original equipment left.

He was certainly hard to kill. His inhuman body carried Mao Feidu through many more missions, and he became the longest-serving captain, until he began to notice a marked decline in his thinking. A brain of flesh could not, after all, be taken in for regular servicing and an overhaul. Beside all those prosthetics requiring maintenance or even replacement, the brain was an engineering miracle. It used extraordinarily little energy, packed everything into a compact structure, and had a working life far beyond that of the human body itself, with more specialized circuits for thought than one could count. Apart from its exacting operating conditions and the difficulty of maintaining and regenerating it, it was practically perfect. If the brain–computer interface had not kept wearing away his neurons, Mao Feidu might have stayed clearheaded enough to spend another few decades getting up to things in space.

Two hundred years had passed since his first perilous voyage. The Alliance already had quite satisfactory remedies for this small problem with his brain. Culture somatic cells, induce them to differentiate anew into neurons, and use them to replace aging cells bit by bit. The neural pathways had to be kept as intact and consistent as possible throughout, to ensure that the person remained the same person. These were merely the established, legal techniques. The underground market offered further, illegal services for the brain: copying or transplanting neural circuitry, for example, or actual brainwashing through the restructuring of neurons. The intentions behind such operations might not be entirely malicious, but they already posed a serious challenge to society. What, fundamentally, identified a person within society? The body, the ID, social identity, the brain, the contents of thought—or something else?

Unfortunately, none of these legal or illegal methods could treat Mao Feidu’s brain. Not because he cared about such airy existential questions, but because his flesh content was a little too low: the conditions needed to maintain the original brain were simply absent. There was, however, another way. Mao Feidu and Courage had spent more than two centuries carrying out missions together, and the ship’s computers had accumulated an immense amount of data on his behavior. Since he already had a brain–computer interface, they could gradually build a mirror of him. Give the procedure a flattering name, and it was neural uploading. But neural uploading in the true sense was impossible; the supposed transfer was a conceptual illusion. The flesh-and-blood Mao Feidu would gradually decay, while a cybernetic prosthesis mimicking him would progressively take over what was lost, until his brain deteriorated too far to sustain the interface. Mao Feidu himself would notice nothing unusual in the process. Still less would anyone else.

The plan had only a few small flaws. No one in the Alliance had ever turned himself into a cybernetic mimic before. Was this gradual substitution treatment or end-of-life care? Once the substitution was complete, should cyber-Mao Feidu inherit every relationship belonging to the original? These questions required careful consideration. Fortunately, Mao Feidu was already a cyborg, and in his day-to-day life was much like a potted plant growing aboard the ship. His relationships were not particularly complicated. There was another, more frightening point: the brain that could no longer sustain its interface would not be dead. It should retain some ability to think, but would have lost the physical means of communicating with the outside world. Under existing Alliance law, this would apparently qualify as a vegetative state, though the patient would still legally be a person. People in vegetative states could awaken. A brain in a jar might recover, too. Perhaps some sudden technological breakthrough would let the Alliance induce aging cells to differentiate again and repair them. Which was Mao Feidu—the brain that could not speak from its jar, or the cybernetic mimic inside the main computer? Aside from the legal and sociological obstacles, there was one other small problem: his choice of cybernetic brains was rather limited. In fact, only Courage’s main computer could accommodate him.

None of this was a problem for Mao Feidu, who felt he had already had his money’s worth out of life. Let the law and ethics be someone else’s headache. To stop going forward was no different from dying. Whether the Mao Feidu in the jar or the cyber-Mao Feidu aboard Courage, either would agree without hesitation. A body that could not move was, to him, a prison worse than death. To keep exploring in a freer form was what he had always wanted. Besides, he was already a hybrid containing less than five percent human. Throwing away that last little bit was no great matter.

And so, after ten years of substitution, Mao Feidu’s brain in its jar—or perhaps Mao Feidu himself—went into a museum in place of Courage. His characteristics had been transplanted into the ship’s main computer. One could say that cyber-Mao Feidu now lived inside that computer, or that the computer had become an artificial intelligence with a distinct flavor of Mao Feidu. Courage/Mao Feidu preferred to say that he had become the ship’s spirit. From then on, Courage was the only intelligent vessel in the Alliance whose right to act on its own behalf was recognized by law.

Without that status, it could never have become the legend that opened the Age of the Great Passage.

Interstellar travel was impossible. At least, that was how things stood in the Alliance’s planetary system, and before the discovery of the Great Passage, everyone believed it. The universe was simply too large. The neighboring star systems were too remote, if one could even call them neighbors. All the matter and energy in this planetary system would not suffice for so long a journey. Indeed, the problem went much further. Even interstellar communication was almost impossible. What if a signal traveled at the speed of light? It would still be an ant crossing the sea, an ant climbing into the sky. Any signal the Alliance could send would inevitably dissipate and distort across the endless expanse, redshift as the universe expanded, and become too faint to distinguish—or simply dissolve into the background radiation.

If the Alliance had thought of the stars only as a painting on the vault of heaven, if those faint lights at night had been merely signs for mysterious divinations, then the size of the heavens would not have mattered. But the Alliance had developed spaceflight and grown into an immense civilization spread across its planetary system. In ignorance, it had felt nothing. Having truly ventured into the stars, it could no longer accept such a fate. The system’s sun had a long life left, but it would eventually end. No finite expanse, however vast, could contain infinite possibilities. What if the voyage were not so difficult? What if the empty wilderness of space were not really so empty?

Thus Courage set out on a voyage from which there would be no return. This was truly a plan for an ant to cross the sea. Uncrewed probes were, after all, no more than stones thrown ahead to test the way, while a ship with a living crew could not endure the ages the journey would take. Courage alone could do it—and was more than willing to become that explorer. It would set its course for unreachable starlight and enter the endless dark. The thin interstellar gas that might, in theory, exist would be its only source of supplies along the way. To borrow a comparison from distant Earth, it would be like paddling a dugout canoe across a windless ocean, powered only by muscle and fueled only by fish caught at sea. A dugout crossing the doldrums had actually been achieved. Courage’s journey was all but beyond possibility.

Courage and the Alliance were fortunate. They had taken a brave step off a cliff and found their foot on a stairway into the sky. The ship was heading for the strangest object visible from the Alliance. Its spectrum was the most complex of all, unlike the red or yellow light of the other visible stars. In theory, it ought to be the nearest object, yet even in that dim sky it was comparatively faint. This was the direction Courage had chosen to try. Two hundred years later, it had only just reached the edge of the planetary system when this strange “star” surrendered its secret.

A road through the heavens.

Countless stars and galaxies outlined a perfect sphere against the blackness. It was about the size of those asteroids just large enough to become spherical, like a small universe circling a star on the system’s edge. This was no physical celestial body, but an unusual structure in space. The light and gravity of remote stars passed through the spherical stargate. Their pull was wholly unlike that of the dim stars in the black background, visible but forever beyond reach.

Courage sent everything it had learned back to the home it had left, and several years later a reply finally arrived. This was a major discovery in cosmology, offering a possible explanation for the universe’s missing mass. Perhaps it was not dark matter that existed—or rather, what was missing was not invisible mass, but distance itself. Such structures would be scattered throughout the universe, distributed around celestial bodies in accordance with the distribution of mass. The network of starways as a whole would act like rivets set into space, allowing gravity to pull the universe together along paths shorter than the observed distances.

Courage became the greatest legend in the Alliance’s history. It could decelerate and return. The Alliance would rebuild it using the advances of the past two hundred years—and the latest technology of nearly four hundred years by the time of its return—so that it could set out on a new voyage in a more nearly perfect form. But there was another choice, far more tempting. After sending back further observations, Courage sailed straight into the stargate without waiting for the next reply.