When humanity first crossed from star to star, people called the spacecraft they used slow ships. Slow ships were faster than any means of transportation humanity possessed at the time, but they were slower than light. For that reason, those who departed might not reach their destinations. The first voyages did not have to end within a single person's lifetime. When the generation that had departed died, the next generation took over the ship, and if they too failed to arrive, another generation took over. Some boarded knowing from the beginning that they would never see their destination. On the early slow ships, speed was not a measure of failure. What mattered was that they would arrive.
Slow ships were not fast enough, but they could make use of time. Decades and centuries could be included in the same plan, and some voyages were remembered by the names of their destinations rather than by the names of those who had departed. People did not consider it strange to begin something that would last longer than their own lives.
Even after wormholes were created, slow ships did not disappear immediately. To carry the entrance of a new passage to its destination, a slow ship was still needed at first. Two entrances were created in the same place, and one was loaded onto a ship and transported to another star system. Only after the entrance arrived did the distance between the two locations disappear within the passage. At the beginning of every fast route, there had first been a slow ship.
The galaxy's early passage network was built along the routes left by slow ships. For some ships, new technology was developed before they reached their destinations, while others installed the first entrance of a passage only hundreds of years after departure. By the time they arrived, the government that had existed when they departed had sometimes disappeared, and in other cases the company with which they had originally contracted no longer existed. Still, the ships continued. Slow ships had destinations, and those destinations had been determined at departure.
As galactic civilization expanded, this method gradually came to be regarded as inefficient. Projects in which one generation made the decisions and another received the results had unclear lines of responsibility. Plans that would be completed hundreds of years later were difficult to evaluate against present budgets, and there was a strong possibility that their technology would be obsolete by the time they arrived.
Whenever a faster method appeared, slow ships were pushed further aside. At first, it was a matter of speed. Later, it became a matter of attitude. Traveling quickly was regarded as progress, and answering quickly was regarded as competence. Tasks that required a long time began to appear to be the result of inadequate technology, slow judgment, or flawed planning. Waiting gradually became an action that required explanation.
Within the galaxy, this change caused no great problem. As the passage network expanded, distance disappeared from everyday life. People no longer had to devote their lifetimes to reaching another star system. Those who departed arrived, those who asked questions heard the answers, and those who issued orders could confirm the results.
Children learned about slow ships in history classes. They asked why people in the past had boarded ships when they would never even see their destinations. Textbooks explained it as the pioneering spirit. Older records contained another expression. They went because they could. For citizens of the later galaxy, that sentence was difficult to understand.
After reaching the edge of the galaxy, they could see other galaxies. The nearest galaxy was dozens of times farther away than the diameter of their own galaxy. There was no wormhole entrance there. To build a passage, they would have to do the same thing they had done at the beginning. One entrance would have to be placed aboard a slow ship and sent there. The difference was the distance. Early interstellar voyages were a matter of decades or centuries, sometimes thousands of years. A voyage to another galaxy required millions of years.
The engineers did not say it was impossible. The ship could be built. A propulsion system capable of operating for long periods could be designed, and artificial intelligence capable of continuing the voyage already existed. The passengers did not need to arrive in the same bodies. Memories could be stored, reproductive cells and embryos could be preserved, and new bodies could be created after arrival. If the ship's lifespan was insufficient, it could be designed to repair itself. If necessary, it could even build a new ship during the voyage. The problem was that time was longer than a human life. Who would decide to depart? Who would pay the cost? Who would confirm, millions of years later, whether it had succeeded? Exploration agencies calculated potential routes and prepared designs for slow ships. They recruited volunteers, but almost none came forward. Some said it did not matter if they themselves did not arrive. It would be enough for copies of their memories or their descendants to arrive. Yet no one could be certain whether a being millions of years in the future could be regarded as the same traveler as the person departing now, or whether the destination chosen at departure would still exist by then.
Slow ships regained their old meaning. Ships on which the person who departed might not be the person who arrived. The later galactic civilization found this idea difficult to accept. Plans that used energy in the present for results millions of years in the future received low priority in almost every review. Because the probability of failure could not be calculated precisely, more backup systems were added, and the ships grew larger. As the ships grew, so did their energy requirements. While the plans were being reviewed again, the possibility of better propulsion technology emerging was raised. The argument that waiting a little longer would make it possible to build faster ships was always reasonable. Departures were postponed, and the same argument was repeated generations later.
The best reason not to launch a slow ship was always the possibility that a faster ship would be developed in the future. Eventually, speed became more than a measure of a means of transportation. Being fast changed from meaning that time could be saved to meaning that there was no need to wait. Civilization gradually came to regard only those undertakings whose results could be witnessed directly as matters of the present. Projects completed after one's death belonged to the future. A ship that might arrive after one's civilization had disappeared was difficult to recognize as a project of the present. Those willing to board slow ships also disappeared. It was not because they had become more fearful. Citizens of the galaxy approached black holes, passed through unstable passages, and were restored in new bodies many times. Personal danger had long since become ordinary. What they found harder to endure than death was delay. Not being able to see the result. Not being able to receive an answer. The possibility that something they had begun might end only after they had become someone with no connection to the person who had started it. Early humanity had accepted this as a matter of course. The later civilization experienced it as a failure.
Slow ships bound for other galaxies never became a regular undertaking. The designs remained, the routes had been calculated, and most of the necessary technology existed. The ships simply never departed. Galactic civilization created wormholes and eliminated distance. Once distance disappeared, waiting disappeared as well. Once waiting disappeared, the number of humans capable of waiting also declined. Slow ships were not a technology abandoned because they were too slow. Nor had they become unnecessary because faster technology had emerged. When humanity first crossed between stars, those who boarded slow ships departed knowing that they might never see their destinations. After connecting the entire galaxy, people did not depart for destinations millions of years away. They could build the ships. They could send them. There was a possibility that they would arrive. Yet no one wanted to travel through a time that was not their own.