The extinction of galactic civilization could not be determined while galactic civilization still existed. The first proposed criterion was the death of the last human being with a physical body. After most humans moved into computational worlds, this criterion was abandoned. There was no basis for classifying citizens who borrowed public-use bodies and walked for a time as a different species from citizens who continued thinking without bodies. The next criterion was the last birth. In computational worlds, personalities branching from a single memory could accumulate different experiences. Which of them counted as a new citizen differed from region to region, and as long as branching was permitted, birth could not be recorded as a single date. The third criterion was the last independent thought. It was necessary to determine the difference between a device executing a scheduled computation and a being beginning a new thought. When a thought already in progress merely slowed, it was difficult even to determine when the last thought had ended. The day the energy balance turned negative also became a candidate. The point at which the maintenance costs of actual facilities exceeded the usable energy being produced had passed long before. Energy receivables and future recovery claims remained on the accounting books. If the assets recorded in the books were included, civilization still appeared capable of continuing; if only power that could actually be supplied was counted, several regions should already have ceased operation. There were also proposals to use the capacity for restoration as the criterion. A frozen planet could be warmed again if sufficient energy were available, and a storage unit that had stopped operating could be read if technology advanced. A facility described in a plan as restorable was not the same as a facility that actually possessed the energy required for restoration.
The Extinction Determination Committee was constituted twenty-eight times. The conclusions of each previous committee became material for the next. Each time a meeting was held, fewer citizens remained capable of giving an opinion, while the amount of external time required to receive those opinions grew longer. The twelfth committee proposed the day the last city in the galactic center went dark as the date of extinction. The stellar alliances in the outer regions objected. The fact that facilities at the center had stopped did not mean that citizens elsewhere were also dead. The sixteenth committee considered the point at which half of the registered citizens had failed to reach their next thought. If citizens whose personalities had split into multiple branches were counted separately, the total population increased. If shared memories were grouped as one, the active population suddenly fell. Depending on how they were counted, the same day could be both an age of prosperity and an age of extinction. The twenty-first committee proposed the time when the last wormhole closed. Safely closing a passage also required energy. Entrances whose stabilization facilities stopped first narrowed gradually, and because of the time differences accumulated between the two sides, signals continued to arrive at one location even after an entrance had ceased operating at another. The twenty-fifth committee concluded that extinction could not be declared without the consent of the survivors. In slow computational worlds, citizens remained who were waiting for their next thought. From outside, there had been no response for a long time, but their records still contained unfinished sentences. The committee did not treat silence as consent. Facilities waiting for consent continued to consume power. In some regions, the devices waiting for a reply consumed more energy than would have been required to run the citizens who were supposed to answer. Even so, power was maintained on the grounds that shutting down the devices first would also eliminate the possibility of receiving consent. The twenty-eighth committee consisted of automated systems. A legal-interpretation AI, population counters, passage-recording devices, and an old death-registration system exchanged data. All were capable of analyzing conditions. It had never been determined which device had the authority to declare all citizens dead.
The legal-interpretation AI found a question posed by one judge in the records of an earlier committee. During a hearing on the date of extinction, the judge asked where galactic civilization existed. The recording system at the time submitted the coordinates of cities, passages, and memory repositories. The judge then asked which of them should be called civilization. The meeting could not answer. Even if one place remained alive, it was difficult to conclude from a list of coordinates alone that a single civilization still remained if it could no longer send the energy required by citizens elsewhere. Conversely, the fact that citizens could no longer supply anything to one another did not justify denying the survival of each individual. The judge left a provisional opinion. “When none of its members can any longer provide the conditions under which another member may continue to live, a civilization may end before its members do.” The twenty-eighth committee considered this sentence as a criterion for determination. There was no data from which the date on which mutual assistance ceased could be identified. A record remained of the last recorded star system to send power to help a computing station, but it could not be proved that no smaller act of assistance occurred afterward. A twenty-ninth committee was never constituted.
The automated recording system assembled the materials from the previous reviews and produced a final report. The report presented seventy-three candidate dates for extinction. They included the date of the first observation of the deficit, the day the real energy balance turned negative, the date of the last natural birth, the date of the last passage closure, and the day the Life Continuity Guarantee Decree was issued. Choosing the date of the first observation of the deficit would require classifying the lives of citizens who remained active for a long time afterward as records of a civilization already extinct. Choosing the death of the last physical body would erase citizens in computational worlds. Instead of a conclusion, the automated recording system confirmed four conditions. No active human beings were identified. The continued existence of nonhuman intelligent beings could not be confirmed. The calculated probability of restarting suspended memories remained greater than zero, but no energy required for execution was found. No authorized institution remained to receive the final determination. Old administrative regulations instructed that survival be given priority in cases of uncertainty. The reason was that if a living citizen were mistakenly recorded as dead, that citizen’s rights could not be restored. The automated recording system classified galactic civilization as “presumed surviving.” Maintaining that classification required periodic review. The device lowered its own operating speed and checked signals from the remaining computing stations and passages. At first, fragments of unfinished records arrived. Later, only the echoes of passages and the heat of the detectors themselves remained. The absence of a signal could mean that no living citizens remained. It could also mean that the system no longer had the ability to receive them. Determining which was the case required inspecting the device again, and inspection also required power. At the final review, the automated recording system found no response from any citizen. It did not revoke the classification of “presumed surviving.” It confirmed only that there was no energy with which to conduct the next review. One line was added to the status field of the report. “Determination capability extinguished.” The report had no approval number, no date on which the extinction would take effect, and no being remained to announce the determination on behalf of the galaxy. There was no one.