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 engram; 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 microtubule 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, tubulin 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.
So now the best current model had it that memories were encoded (somehow) as standing patterns of quantumcoherent oscillations, set up by changes in the microtubules and their constituent parts, all working in patterns inside the neurons. Although there were now researchers who speculated that there could be significant action at even finer ultramicroscopic levels, permanently beyond their ability to investigate (familiar refrain); some saw traces of signs that the oscillations were structured in the kind of spin-network patterns that Bao’s work described, in knotted nodes and networks that Sax found eerily reminiscent of the palace-of-memory plan, utilizing rooms and hallways, as if the ancient Greeks by introspection alone had intuited the very geometry of timespace.
In any case, it was sure that these ultramicroscopic actions were implicated in the brain’s plasticity; they were part of how the brain learned and then remembered. So memory was happening at a far smaller level than had been previously imagined, which gave the brain a much higher computational possibility than before, up to perhaps 1024 operations per second— or even 1043 in some calculations, leading one researcher to note that every human mind was in a certain sense more complicated that all the rest of the universe (minus its other consciousnesses, of course). Sax found this suspiciously like the strong anthropic phantoms seen elsewhere in cosmological theory, but it was an interesting idea to contemplate.
So, not only was there simply more going on, it was also happening at such fine levels that quantum effects were certainly involved. Experimentation had made it clear that large-scale collective quantum phenomena were happening in every brain; there existed in the brain both global quantum coherence, and quantum entanglement between the various electrical states of the microtubules; and this meant that all the counterintuitive phenomena and sheer paradox of quantum reality were an integral part of consciousness. Indeed it was only very recently, by including the quantum effects in the cytoskeletons, that a team of French researchers had finally managed to put forth a plausible theory as to why general anesthetics worked, after all the centuries of blithely using them.
So they were confronted with yet another bizarre quantum world, in which there was action at a distance, in which decisions not made could affect events that really happened, in which certain events seemed to be triggered teleologically, that is to say by events that appeared to come after them in time. . . . Sax was not greatly surprised by this development. It supported a feeling he had had all his life, that the human mind was deeply mysterious, a black box that science could scarcely investigate. And now that science was investigating it, it was coming up hard against the great unexplainables of reality itself.
Still, one could hold to what science had learned; and admit that reality at the quantum level behaved in ways that were simply outrageous at the level of human senses and ordinary experience. They had had three hundred years to get used to that, and eventually they had somehow to incorporate this knowledge into their worldviews, and forge on. Sax would have indeed said that he was comfortable with the familiar quantum paradoxes; things at the microscale were bizarre but explicable, quantifiable or at least describable, using complex numbers, Riemannian geometry, and all the rest of the armatures of the appropriate branches of mathematics. Finding such stuff in the very workings of the brain should have been no surprise at all. Indeed, compared to things like human history or psychology or culture, it was even somehow comforting. It was only quantum mechanics after all. Something that could be modeled by mathematics. And that was saying something.
So. At an extremely fine level of structure in the brain, much of one’s past was contained, encoded in a unique complex network of synapses, microtubules, dimers and vicinal water and amino-acid chains, all small enough and near enough together to have quantum effects on each other. Patterns of quantum fluctuation, diverging and collapsing; this was consciousness. And the patterns were clearly held or generated in specific parts of the brain; they were the result of a physical structure articulated on many levels. The hippocampus, for instance, was critically important, especially the dentate gyrus region and the perforant pathway nerves that led to it. And the hippocampus was extremely sensitive to action in the limbic system, directly underneath it in the brain; and the limbic system was in many ways the seat of the emotions, what the ancients would have called the heart. Thus the emotional charge of an event had much to do with how fully it was laid out in the memory. Things happened, and the consciousness witnessed or experienced them, and inevitably a great deal of this experienced changed the brain, and became part of it forever; particularly the events heightened by emotion. This description seemed right to Sax; what he had felt most he remembered best— or forgot most assiduously, as certain experiments suggested, with an unconscious constant effort that was not true forgetting at all, but repression.
After that initial change in the brain, however, the slow process of degradation began. For one thing, the power of recollection was different in different people, but always less powerful than memory storage, it appeared, and very hard to direct. So much was patterned into the brain but never retrieved. And then if one never remembered a pattern, never recollected and rehearsed it, then they never got the reinforcement of another run-through; and after about 150 years of storage, experiments suggested, the pattern began to degrade more and more rapidly, due apparently to the accumulated quantum effects of free radicals collecting randomly in the brain. This was apparently what was happening to the ancient ones; a breakdown process which began immediately after an event was patterned into the brain, eventually hit a cumulative level where the effects were catastrophic for the oscillatory patterns involved, and thus for the memories. It was probably about as clocklike, Sax thought glumly, as the thermodynamic clouding of the lens of the eye.
However— if one could rehearse all one’s memories, ecphorize them as some called it in the literature on the subject— from the Greek, meaning something like “echo transmission”— then it would reinforce the patterns, giving them a fresh start and setting the clock of degradation back to zero. A sort of longevity treatment for dimer patterns, in effect, sometimes referred to in the literature as anamnesis, or loss of forgetting. And after such treatment it would be easier to recall any given event, or at least as easy as it had been soon after the event happened. This was the general direction that work in memory reinforcement was taking. Some called the drugs and electrical devices involved in this process nootropics, a word which Sax read as “acting upon mind.” There were a lot of terms for the process being bandied about in the current literature, people scrambling through their Greek and Latin lexicons in the hope of becoming the namer of the phenomenon: Sax had seen mnemonics and mnemonistics, and mnemosynics, after the goddess of memory; also mimenskesthains, from the Greek verb “to remember.” Sax preferred memory reinforcer, although he also liked anamnesis, which seemed the most accurate term for what they were trying to do. He wanted to concoct an anamnestic.
But the practical difficulties of ecphorization— of remembering all one’s past, or even some particular part of it— were great. Not just finding the anamnestics that might stimulate such a process, but finding as well the time it would take! When one had lived two centuries, it seemed possible that it might take years to ecphorize all the significant events of one’s life.
Clearly a sequential chronological run-through was impractical, in more ways than one. What would be preferable was some kind of simultaneous flushing of the system, strengthening the entire network without consciously remembering every component of it. Whether such a flushing was electrochemically possible was unclear; and what such a flushing might feel like was impossible to imagine. But if one were to electrically stimulate the perforant pathway to the hippocampus, and get a great deal of adenosine triphosphate past the blood-brain barrier, for instance, thus stimulating the long-term potentiation that aided learning in the first place; and then impose a brain-wave pattern stimulating and supporting the quantum oscillations of the microtubules; and then direct one’s consciousness to review the memories that felt most important to one, while the rest were being reinforced as well, unconsciously. . . .
He ran through another accelerando of thought on this issue, then crashed blank on it. There he was, sitting in his apartment living room, blanked, cursing himself for not at least trying to mutter something into his AI. It seemed that he had been onto something— something about ATP, or was it LTP? Well. If it was a genuinely useful thought, it would come back. He had to believe that. It seemed probable.
As it did, more and more as he studied the issues, that the shock of Maya’s amnesiac moment had somehow propelled Michel into the quick decline. Not that such an explanation could ever be proved, or that it even really mattered. But Michel would not have wanted to survive either his memory or hers; he had loved her as his life project, his definition of himself. The shock of Maya blanking on something so basic, so important (like the key to memory restoration). . . . And the mind-body connection was so strong— so strong that the distinction itself was probably false, a vestige of Cartesian metaphysics or earlier religious views of the soul. Mind was one’s body’s life. Memory was mind. And so, by a simple transitive equation, memory equaled life. So that with memory gone, life was gone. So Michel must have felt, in that final traumatic half hour, as his self tumbled into a fatal arrhythmia, under the anguish of grieving for his love’s death-of-mind.
They had to remember to be truly alive. And so ecphorization, if he could figure out the appropriate anamnestic methodology, was going to have to be tried.
• • •
Of course it might be dangerous. If he did manage to work up a memory reinforcer, it would flush the system all at once, perhaps, and no one could predict what that would feel like subjectively. One would just have to try it. It would be an experiment. Self-experimentation. Well, it wouldn’t be the first time. Vlad had given himself the first gerontological treatment, though it could have killed him; Jennings had inoculated himself with live smallpox vaccine; Arkady’s ancestor Alexander Bogdanov had exchanged his blood for that of a young man suffering from malaria and tuberculosis, and had died while the young man had lived for thirty more years. And of course there was the story of the young physicists at Los Alamos, who had set off the first nuclear explosion wondering among themselves whether it might not burn up the entire atmosphere of the Earth, a somewhat disturbing case of self-experimentation, one had to admit. Compared to that ingesting a few amino acids seemed no very great thing, something more like Dr. Hoffman trying LSD on himself. Presumably ecphorizing would be less disorienting than an LSD experience, for if all one’s memories were being reinforced at once, consciousness would surely not be capable of being aware of it. The so-called stream of consciousness was fairly unilinear, it seemed to Sax on introspection. So that at most one might experience a quick associative train of recollections, or a random jumble— not unlike Sax’s everyday mentation, to tell the truth. He could handle that. And he was willing to risk something more traumatic, if that was what it happened to take.
He flew to Acheron.
Up at Acheron a new crowd was in place in the old labs, now vastly expanded, so that the entire high long fin of rock was excavated and occupied— it was a city now of some 200,000 people. At the same time it was still, of course, a spectacular fin of rock some fifteen kilometers long and six hundred meters high, while never more than a kilometer wide at any point; and it was still a lab, or a complex of labs, in a way that Echus Overlook had long since ceased to be— something more like Da Vinci, with a similar organization. After Praxis had renovated the infrastructure, Vlad and Ursula and Marina had led the formation of a new biological research station; now Vlad was dead, but Acheron had a life of its own, and did not seem to miss him. Ursula and Marina directed their own little labs, and lived still in the quarters they had shared with Vlad, just under the crest of the fin— a partially walled arboreal slot, very windy. They were as private as ever, withdrawn into their own world even more than they had been with Vlad; and they were certainly taken for granted in Acheron, treated by the younger scientists as local grandmothers or great-aunts, or simply as colleagues in the labs.
Sax, however, the younger scientists stared at, looking just as nonplussed as if they were being introduced to Archimedes. It was as disconcerting to be treated in such a way as it was to meet such an anachronism, and Sax struggled through several conversations of surpassing awkwardness as he tried to convince everyone that he did not know the magic secret of life, that he used words to stand for the same things as they did, that his mind was not yet altogether shattered by age, etc.
But this estrangement could also be an advantage. Young scientists as a class tended to be naive empiricists, also idealistic energetic enthusiasts. So coming in from outside, both new and old at once, Sax
was able to impress them in the seminars Ursula convened to discuss the current state of memory work. Sax laid out his hypotheses concerning the creation of a possible anamnestic, with suggestions for various lines of experimental work on these possibilities, and he could see that his suggestions had for the young scientists a kind of prophetic power, even (or perhaps especially) when they were quite general comments. If these vague suggestions happened to chime with some avenue these people were already exploring, then the response could be enthusiastic in the extreme. In fact it was a case of the more gnomic the better; which was not very scientific, but there it was.
As he watched them Sax realized for the first time that the versatile, responsive, highly focused nature of science that he was getting used to in Da Vinci was not confined to Da Vinci alone, but was a feature of all the labs arranged as cooperative ventures; it was the nature of Martian science more generally. With the scientists in control of their own work, to a degree never seen in his youth on Earth, the work itself had an unprecedented rapidity and power. In his day the resources necessary to do the work would have belonged to other people, to institutions with their own interests and bureaucracies, creating a ponderous and often foolish clumsy scattering of effort; and even the coherent efforts were often devoted to trivial things, to the monetary profits of the institution in control of the lab. Here, on the other hand, Acheron was a semiautonomous self-contained community, answerable to the environmental courts and to the constitution of course, but to no one else. They chose among themselves what to work on, and when they were asked for help, if they were interested, they could respond immediately.
So he was not going to have to do all the work of developing a memory reinforcer himself, not by any means; the Acheron labs were highly interested, and Marina remained active in the city’s lab of labs, and the city still had a close relationship with Praxis, with all its resources. And many labs there were already investigating memory. It was a big part of the longevity project now, for obvious reasons. Marina said that some twenty percent of all human effort was now being devoted, in one form or another, to the longevity project. And longevity itself was pointless without memory lasting as long as the rest of the system. So it made sense for a complex like Acheron to focus on it.