And all this vast articulated structure of a culture stood out in the open sun of day, accessible to anyone who wanted to join, who was willing and able to do the work; there were no secrets, there were no closed shops, and if every lab and every specialization had its politics, that was just politics; and in the end politics could not materially affect the structure itself, the mathematical edifice of their understanding of the phenomenal world. So Sax had always believed, and no analysis by social scientists, nor even the troubling experience of the Martian terraforming process, had ever caused him to waver in that belief. Science was a social construct, but it was also and most importantly its own space, conforming to reality only; that was its beauty. Truth is beauty, as the poet had said, speaking of science. And it was; the poet had been right (they weren’t always).

And so Sax moved about in the great structure, comfortable, capable, and on some levels content.

But he began to understand that as beautiful and powerful as science was, the problem of biological senescence was perhaps too difficult. Not too difficult to be solved ever, nothing was that, but simply too difficult to be solved in his lifetime. Actually it was still an open question how hard a problem it was. Their understanding of matter, space and time was incomplete, and it might be that it would always necessarily shade off into metaphysics, like the speculations about the cosmos before the Big Bang, or things smaller than strings. On the other hand the world might be amenable to progressive explanations, until it all (at least from string to cosmos) would be brought someday within the realm of the great parthenon. Either result was possible, the court was still out, the next thousand years or so should tell the tale.

But in the meantime, he was experiencing several blank-outs a day. And sometimes he was short of breath. Sometimes his heart seemed to beat so hard. Seldom did he sleep at night. And Michel was dead, so that Sax’s sense of the meaning of things was becoming uncertain, and in great need of help. When he managed to think at all on the level of meaning, he found that he felt he was in a race. Him and everyone else, but especially the life scientists actually at work on the problem: they were in a race with death. To win it, they had to explain one of the greatest of the great unexplainables.

And one day, sitting down on a bench with Maya after a day in front of his screen, thinking of the vastness of that growing wing of the parthenon, he realized that it was a race he couldn’t win. The human species might win it, someday, but it looked to be a long way off still. It was no great surprise, really; he knew this; that is to say, he had always known it. Labeling the current largest manifestation of the problem had not disguised to him its profundity, “the quick decline” was just a name, inaccurate, over-simple — not science, in fact, but rather an attempt (like “the Big Bang”) to diminish and contain the reality, as yet not understood. In this case the problem was simply death. A quick decline indeed. And given the nature of life and of time, this was a problem that no living organism would ever truly solve. Postponements, yes; solutions, no. “Reality itself is mortal,” he said.

“Of course,” Maya said, absorbed in the sight of the sunset.

He needed a simpler problem. As a postponement, as a step toward the harder problems; or just as something he could solve. Memory, perhaps. Fighting the blank-outs; it was certainly a problem that stood at hand, ready for study. His memory was in need of help. Working on it might even cast light on the quick decline. And even if it didn’t, he had to try it, no matter how hard it was. Because they were all going to die; but they could at least die with their memories intact.

So he switched his emphasis to the memory problem, abandoning the quick decline and all the rest of the senescence issues. He was only mortal after all.

Recent memory work was fairly suggestiveof avenues of approach. This particular scientific front was related in some of its aspects to the work on learning that had enabled Sax to (partially) recover from his stroke. This was not surprising, as memory was the retention of learning. All brain science tended to move together in its understanding of consciousness. But in that progression, retention and recall remained recalcitrant crux issues, still imperfectly understood.

But there were indications, and more all the time. Clinical clues; a lot of the ancient ones were experiencing memory problems of varying kinds, and behind the ancient ones came a giant generation of nisei, who could see the problems manifesting in their elders, and hoped to avoid them. So memory was a hot topic. Hundreds, indeed thousands of labs were working on it in one way or another, and as a result many aspects of it were coming clear. Sax immersed himself in the literature in his usual style, reading intensively for several months on end; and at the end of that time he thought he could say, in general terms, how memory worked; although in the end he, like all the rest of the scientists working on the problem, ran into their insufficient understanding of the underlying basics — of consciousness, matter, time. And at this point, as detailed as their understanding was, Sax could not see how memory might be improved or reinforced. They needed something more.

The original Hebb hypothesis, first proposed by Donald Hebb in 1949, was still held to be true, because it was such a general principle; learning changed some physical feature in the brain, and after that the changed feature somehow encoded the event learned. In Hebb’s time the physical feature (the engram) was conceived of as occurring somewhere on the synaptic level, and as there could be hundreds of thousands of synapses for each of the ten billion neurons in the brain, this gave researchers the impression that the brain might be capable of holding some 1014 data bits; at the time this seemed more than adequate to explain human consciousness. And as it was also within the realm of the possible for computers, it led to a brief vogue in the notion of strong artificial intelligence, as well as that era’s version of the “machine fallacy,” a variant of the pathetic fallacy, in which the brain was thought of as being something like the most powerful machine of the time. The work of the twenty-first and twenty-second century, however, had made it clear that there were no specific “engram” sites as such. Any number of experiments failed to locate these sites, including one in which various parts of rat’s brains were removed after they learned a task, with no part of the brain proving essential; the frustrated experimenters concluded that memory was “everywhere and nowhere,” leading to the analogy of brain to hologram, even sillier than all the other machine analogies; but they were stumped, they were flailing. Later experiments clarified things; it became obvious that all the actions of consciousness were taking place on a level far smaller even than that of neurons; this was associated in Sax’s mind with the general miniaturization of scientific attention through the twenty-second century. In that finer-grained appraisal they had begun investigating the cytoskeletons of neuron cells, which were internal arrays of microtubules, with protein bridges between the microtubules. The microtubules’ structure consisted of hollow tubes made of thirteen columns of tubulin dimers, peanut-shaped globular protein pairs, each about eight-by-four-by-four nanometers, existing in two different configurations, depending on their electrical polarization. So the dimers represented a possible on-off switch of the hoped-for engrain; but they were so small that the electrical state of each dimer was influenced by the dimers around it, because of van der Waals interactions between them. So messages of all kinds could be propagated along each mi-crotubule column, and along the protein bridges connecting them. Then most recently had come yet another step in miniaturization: each dimer contained about 450 amino acids, which could retain information by changes in the sequences of amino acids. And contained inside the dimer columns were tiny threads of water in an ordered state, a state called vicinal water, and this vicinal water was capable of conveying quantum-coherent oscillations for the length of the tubule. A great number of experiments on living monkey brains, with miniaturized instrumentation of many different kinds, had established that while consciousness was thinking, amino-acid sequences were shifting, tub-ulin dimers in many different places in the brain were changing configuration, in pulsed phases; microtubules were moving, sometimes growing; and on a much larger scale, dendrite spines then grew and made new connections, sometimes changing synapses permanently, sometimes not.