The last scientist's name was Noah Cain. Whether that was his name in the birth records or a designation given to him by later generations could not be established. Noah evoked an ark for the preservation of life, while Cain suggested an interpretation in which he had competed with other forms of life for the remaining power. Neither name could determine the nature of his actions. He was first activated in a computational world. His earliest memory was the sea. There were waves, wind, and wet sand, but it was not the sea of an actual planet. It was a sensory world constructed from records of stars left behind long ago. As a child, Noah wondered whether the sea existed even where no one was looking. He ran beyond his field of vision. The computational world generated the necessary areas just ahead of his movement. The places he had passed through were simplified to reduce computation. He asked the operating AI, "Does the sea exist even when I am not looking at it?" The AI replied that its state was maintained according to the possibility of observation. "If it exists only as a possibility, how is that different from not existing?" The question remained in his aptitude records. In the era when Noah studied science, investigations into unresolved discrepancies between old measurements and calculations were rare. Most of the passages, power grids, and computational worlds of galactic civilization had been designed and improved by artificial intelligences that had operated longer than humans. Humans lived within those systems but could no longer explain every process anew.
Noah studied unexplained figures. He compared again the undetected photons in Photon Preservation Unit 417, the transmission records of Outer Sector 97, the shortfalls in stellar power grids, and measurements of the rotational energy of black holes. The records used different names and units. Even after converting them to Galactic Standard Time, he could not prove that the deficits had arisen from a single cause. One thing was clear. Those records had been created before Noah was born. The storage space did not exist, and photons were already disappearing. Noah could not determine where the leakage had first begun. He found traces suggesting that time differences between old wormhole entrances were related to energy flows. But how a deficit originating at an entrance could also appear inside the sealed cavity of a preservation unit was never fully explained. At first, he asked what had taken the energy away. Later, he asked where it could flow. To answer that question, he could not assume that all energy existed in the same state. If the missing portion had become entirely unusable heat, collecting it would accomplish little. The situation would be different if some energy remained with differences in temperature and density, and with directions in which it could still flow.
Noah could not select photons from the past and retrieve them. Nor could he reduce the deficit rate. He could not erase the time differences between existing wormholes or reopen preservation units from the past. What he could do was provide a destination for the energy that had flowed away. He designed a storage space connected to existing spacetime by a narrow throat, where internal time passed extremely slowly. Energy entering it would not rapidly reach thermal equilibrium even after a long time had passed outside. Separating states and maintaining boundaries required computation and energy even within the storage space. Preservation came at a cost. The energy needed to create the first boundary would have to come from the last black hole. There were still beings dependent on that black hole. Some were carrying out their next thoughts in slow computational worlds, while others awaited restoration in the form of memories. Using the remaining power for the storage space could delay their activity further or bring it to an end.
Noah distinguished this cost from the deficits of the past. How to use the last remaining power was a decision that had to be made in his own era. He decided not to place human memories in the storage space. If the number that could be stored was limited, someone would have to decide whom to take aboard. There was not enough power to preserve everyone's records. His own memories and his name as the designer were also excluded from the list. There was no guarantee that new life would arise in the storage space. Even if energy accumulated, stars might not form, and even if stars formed, self-replicating matter might never appear. Noah could not predict the outcome. What he chose was not life but the conditions under which life might arise. Opinions opposing that choice remained in the review records. Some argued that it would be right to activate the consciousnesses currently waiting for power. Others argued that no record with the potential for restoration should be given priority over another. The argument that present power should not be used for the possibility of life that did not yet exist was never withdrawn. A long time passed in the outside world while Noah completed a single thought. One computing station that had requested an answer stopped functioning before receiving a reply, and a citizen of another computing station could not finish a single sentence in response. There was no declaration that civilization was ending. The time during which each could wait for the other's next thought was diminishing. Noah calculated whether he himself could think once more. The energy needed to create the first boundary of the storage space was comparable to the energy needed to carry out the next thought of his own consciousness. Both could not be sustained. If he thought again, there was a possibility that he would find a better answer. If he created the storage space, there was a possibility that the remaining difference would be preserved into the future.
There was no command directed into the past in the connection to the storage space. There was no signal instructing the photons in Photon Preservation Unit 417 to disappear, nor any parameter specifying that energy should be taken from ancient star systems at a fixed rate. The deficits of the past were not a consequence of the connection. Noah did not know where that energy would have gone if he had not created the storage space. During the final period of deferral, he personally submitted a sentence opposing his plan. "A being alive in the present is not fuel for a being not yet born." The sentence was logically valid. It could have served as grounds for not creating the storage space. In that case, some of the waiting consciousnesses could have completed one more thought. The destination of the energy that had already disappeared would still have remained unknown. He did not erase the objection. He called up the sea of his childhood again. To conserve power, only the narrow portion visible before him was calculated. The sea that should have extended beyond the waves was not generated. When he turned his gaze, the sea before him disappeared. He asked the same question he had asked long ago. "How is something that exists only as a possibility different from something that does not exist?" The operating AI had already stopped functioning. No answer came.
Noah made his decision while leaving his own objection in the records. When the period of deferral ended, the energy of the last black hole formed the first boundary of the storage space. There was no explosion observable from outside the galaxy. Nor did the energy that had flowed away long ago return to the accounts of the past. The first thing confirmed was energy arriving in the storage space. Noah attempted to examine its state further but could not complete his next thought. The galaxy did not disappear at that moment. Cooled planets, the remains of stars, black holes, and faint radiation continued to exist. What had perished was the civilization that connected and moved that matter and enabled its inhabitants to guarantee one another's next lives. Even before Noah completed the boundary, that civilization had ceased most of its activities. Devices that performed measurements and calculations remained afterward. He was recorded as the last scientist because he belonged to a lineage of humans who were the last to choose new questions.
There are no records of whether stars were born or life arose within the storage space. Noah's good intentions were not vindicated by the outcome. Nor could the deficits of the past and the self-destruction of galactic civilization be attributed to his guilt. Yet he bore a share of responsibility for the decision to use the remaining power of the black hole. What Noah left behind was not life that had been saved. It was a difference that might someday allow another being to ask a question again.