His answer to his own question is, yes, a quantum world-view is required. In that world, a particle does not necessarily have a well-defined spin, speed, or position. Rather, it has a number of different possible positions or speeds or spins, and until we make an observation of it, all we can know are the probabilities associated with each possible spin, speed, and position. Only when an observation is made does the particle occupy a well-defined state, in which the measured variable is precisely known. This change, from undefined to well-defined status, is called the “collapse of the quantum mechanical wave function.” It is a well-known, if not well-understood, element of standard quantum theory.
What Penrose suggests is that the human brain itself is a kind of quantum device. In particular, the same processes that collapse the quantum mechanical wave function in sub-atomic particles are at work in the brain. When humans are considering many different possibilities, Penrose argues that we are operating in a highly parallel, quantum mechanical mode. Our thinking resolves and “collapses to a thought” at some point when the wave function collapses, and at that time the many millions or billions of possibilities become a single definite idea.
This is certainly a peculiar notion. However, when quantum theory was introduced in the 1920s, most of its ideas seemed no less strange. Now they are accepted by almost all physicists. Who is to say that in another half-century, Penrose will not be equally accepted when he asserts, “there is an essential non-algorithmic ingredient to (conscious) thought processes” and “I believe that (conscious) minds are not algorithmic entities”?
Meanwhile, almost everyone in the AI community (who, it might be argued, are hardly disinterested parties) listens to what Penrose has to say, then dismisses it as just plain wrong. Part of the problem is Penrose’s suggestion as to the mechanism employed within the brain, which seems bizarre indeed.
As he points out in a second book, Shadows of the Mind (Penrose, 1994), he is not the first to suggest that quantum effects are important to human thought. Herbert Fröhlich, in 1968, noted that there was a high-frequency microwave activity in the brain, produced, he said, by a biological quantum resonance. In 1992, John Eccles proposed a brain structure called the presynaptic vesicular grid, which is a kind of crystalline lattice in the brain’s pyramidal cells, as a suitable site for quantum activity.
Penrose himself favors a different location and mechanism. He suggests, though not dogmatically, that the quantum world is evoked in elements of a neuron known as microtubules. A microtubule is a tiny tube, with an outer diameter of about twenty-five nanometers and an inner diameter of fourteen nanometers. The tube is made up of peanut-shaped objects called tubulin dimers. Each dimer has about ten thousand atoms in it. Penrose proposes that each dimer is a basic computational unit, operating using quantum effects. If he is right, the computing power of the brain is grossly underestimated if neurons are considered as the basic computing element. There are about ten million dimers per neuron, and because of their tiny size each one ought to operate about a million times as fast as a neuron can fire. Only with such a mechanism, Penrose argues, can the rather complex behavior of a single-celled animal such as a paramecium (which totally lacks a nervous system) be explained.
Penrose’s critics point out that microtubules are also found elsewhere in the body, in everything from livers to lungs. Does this mean that your spleen, big toe, and kidneys are to be credited with intelligence?
My own feeling is that Penrose’s ideas sounded a lot better before he suggested a mechanism. The microtubule idea feels weak and unpersuasive.
Fortunately I don’t have to take sides. In the eighth chronicle, I was deliberately silent on how the AI came into existence. However, as a personal observation, I would be much surprised if in our future we do not have human-level AI’s, through whatever method of development, before humans routinely travel to the satellites of Jupiter and Saturn; and I believe that the latter will surely happen in less than five hundred years.
Compressed matter.
We know that compressed matter exists. In a neutron star, matter has been squeezed together so hard that the individual protons and electrons that normally make up atoms have combined to form neutrons. A neutron star with the mass of the Sun can be as little as twenty kilometers across, and a simple calculation tells us that the average density of such a body is about 475 million tons per cubic centimeter. That is still not at the limit of how far matter can be compressed. If the Sun were to become a black hole, as mentioned earlier, its Schwarzschild radius would be about three kilometers and its mean density twenty billion tons per cubic centimeter. McAndrew’s illustrious but unfortunate father developed an unspecified way of squeezing matter down to something between neutron star and black hole densities.
It is easy to calculate what it would be like if you were unwise enough to take hold of a speck of such compressed matter. And it might well be a speck. An eighteen thousand ton asteroid in normal conditions would be a substantial lump of rock about twenty meters across. Squeeze it to a density of three billion tons per cubic centimeter, and it becomes a tiny ball with radius 0.11 millimeters. Its surface gravity is almost ten thousand gees.
The gravitational force falls off rapidly with distance, so if you were a meter away from the mote of matter you would probably be unaware of its existence. It would pull you toward it with a mere ten-millionth of a gee. But take hold of it, and that’s a different story. Ten thousand gees would suck any known material, no matter how strong, toward and into the ball. That process would continue, until either you sacrificed some skin and broke free, or you were eventually totally absorbed. In practice, I think that McAndrew’s father would have realized what was happening and found a way to free himself. He would have plenty of time, because the absorption process into the compressed matter sphere would be slow. That, however, would not have made as interesting a story.
The way that McAndrew’s father produced compressed matter remains pure science fiction. However, the “strong force” itself is an accepted part of modern physics, one of four basic known forces. The other three are gravity, the electromagnetic force, and the so-called “weak force” responsible for beta decay (emission of an electron or positron) in a nucleus. Although there is an adequate theory of the strong force, embodied in what is known as quantum chromodynamics, there is not the slightest hint in that theory of a method to make such a force either stronger or weaker than it is.
That’s all right. Five hundred years ago, magnetism was a curious property of certain materials, and no one knew what it was or had any way of generating it artificially. That had to wait until another strange phenomenon, electricity, had been explored, and experimenters such as Ampère, Oersted, and Faraday proved a link between electricity and magnetism. After that could come Maxwell, providing a unified theory for the two ideas that led to such practical devices as radios, dynamos, and powerful electromagnets.
It is not unreasonable to model the future on the past…A few hundred years from now, maybe we will be able to play our own games with all the known forces in the context of a unified theory, creating or modifying them as we choose. The weak force and the electromagnetic force have already been unified, work for which Glashow, Weinberg, and Salam were awarded the Nobel prize in physics in 1979.
I cannot resist a couple of personal reminiscences regarding the late Abdus Salam. He was my mathematics supervisor when I was a new undergraduate. His personal style of solving the problems that I and my supervision partner brought to him was unique. More often than not, he would look at the result to be derived and say, “Consider the following identity.” He would then write down a mathematical result which was far from obvious and usually new to us. Applying the identity certainly gave the required answer, but it didn’t help us much with our struggles.
Salam also had one endearing but disconcerting habit. He did not drink, but he must have been told that it was a tradition at Cambridge for tutors to serve sherry to their students on holiday occas
ions. He offered my partner and me sherry, an offer which we readily accepted. He then, unfamiliar with sherry as a drink, poured a large tumbler for each of us. We were too polite to refuse, or not to drink what we had been given, but we emerged from the supervision session much the worse for wear.
There is a throwaway comment in the ninth chronicle, that McAndrew was going off to hear a lecture entitled “Higher-dimensional complex manifolds and a new proof of the Riemann Conjecture.” This is a joke intended for mathematicians. In the nineteenth century, the great German mathematician Bernhard Riemann conjectured, but did not prove, that all the zeroes of a function known as the zeta function lay in a certain region of the complex plane. Riemann could not prove the result, and since then no one has managed to do so. It remains the most important unproven conjecture in mathematics, far more central to the field than the long-unproved but finally disposed-of Fermat Last Theorem.
People will keep chipping away at the Riemann conjecture, precisely because it is unproven. Just as we will keep pushing for better observing instruments, more rapid and sophisticated interplanetary or interstellar probes, quantum computers, artificial intelligence, higher temperature superconductors, faster-than-light travel, treatment for all known diseases, and human life extension.
The future in which McAndrew lives is fiction, but I believe that the science and technology of the real future will be far more surprising. There will indeed be ships, built by humans and their intellectual companions, computers, headed for the stars. They will not be powered by Kerr-Newman black holes, nor employ the McAndrew balanced drive, nor will they tap the resonance modes of the vacuum zero-point energy. They will not be multi-generation arks, nor will they find life-bearing planetoids in the Oort cloud, or rogue planets in the interstellar void. What they will be, and what they will find, will be far stranger and more interesting than that. And they will make today’s boldest science fiction conjectures appear timid, near-sighted, small-scale, and lacking in imagination.
Writing of this I wish, like Benjamin Franklin, that I could be pickled in a barrel for a couple of hundred years, to experience the surprising future that I’m sure lies ahead. If I can’t do that and don’t last that long, here is a message to my descendants two centuries from now: On my behalf, make the most of it.
BONUS
Short-story
Following is the last McAndrew story first published in Cosmic Tales: Adventures in Sol System, 2004, edited by T.K.F. Weisskopf.
TENTH CHRONICLE:
McAndrew and the Law
It’s widely accepted that there’s no such thing as a free lunch. I suppose anyone with a brain in her head would realize this applies equally well to dinner, but some people never learn; so there I was, sitting across the table from Professor Limperis and fully expecting him to pick up the tab.
He’s a wily old bird who puts a high value on his time, a fact which I’ve known for as many years as I’ve been visiting the Penrose Institute. And today we were far from there. I was on vacation, ready to follow the progress of the Grand Solo Solar Contest out in the Belt. What were the chances that Limperis had traveled several hundred million kilometers for the doubtful privilege of taking me to dinner?
At the moment he was busy telling me that it was hard times for the Institute, with research budgets squeezed tighter and tighter. I nodded sympathetically, but to be honest my mind was otherwise engaged. I like to gamble on the outcome of the Grand Solo Solar Contest, and a prime entry for the GSSC had just entered the dining room. I guessed that he massed between five and six hundred kilos.
In the GSSC, fat is good because the contest is just what the name suggests. You do the Belt-Jupiter-Mars run alone, with no assistance. “No assistance” means no fuel, no food, no water. Also, no ship. You are provided a suit with an oxygen supply and built-in fusion and chemical drives. Solo means solo. The materials to power the drives have to come from the competitor’s own body.
That’s where judgment enters the picture. The chemical and fusion drives are lipid based, and a competitor draws reaction mass only from his or her own body fat. That’s why the hard-to-say “Grand Solo Solar Contest” is better known as Fat Man’s Run.
With some people, the will to win inevitably takes over. In a pinch, the drives run at reduced power on muscle and sinew. I have seen a competitor, what was left of him, dragged out of the race by the marshals when his total body mass was down to sixty pounds. He might recover, after a fashion, but he would never race again. He would also never walk, run, or have sex, even in low-gee. When I saw him, skin hung off his spongy skeleton like rags on a frame of twigs. And still he was complaining about being removed from the race.
I became aware that Professor Limperis’s eye was on me. He knew I had been distracted by my potential dark horse, and he was quietly waiting.
“I mentioned that finances were tight, Jeanie,” he said at last, “but I didn’t tell you the worst of it. Mac has another pet project stuck in his head, and there’s no way the Institute can afford to do it. I told him that. So he took it on himself to try his hand at fund-raising. He went to Fazool el-Fazool to see if the man could help out.”
That was a real shock. McAndrew fund-raising? Money means less to him than it does to a groundhog.
Limperis saw my look of astonishment and misinterpreted it. “You know Fazool?”
“I’ve never met him. But he’s McAndrew’s mother’s…friend.”
“Ah!” Limperis’s chubby face lit up. “That explains a lot. I only know Fazool as one of the System’s richest people. But if he’s McAndrew’s mother’s—er…”
“Friend.”
“Right. Her friend. Then it makes sense that Mac would get a hearing. More than that, he received a promise of the money he needs for his new project. But there’s a condition.”
“That doesn’t surprise me. Rich people like to stay rich. Fazool will want a return on his investment.”
“It’s not that kind of condition. Fazool wants his son, Abdi el-Fazool, along on the expedition. He says it will be a—er—a broadening experience for the lad.”
I could agree with that. I’ve had near-death experiences with McAndrew all too often.
Limperis was watching my face. “You don’t like the idea?”
“I don’t. How old is Abdi el-Fazool?”
“Eleven.”
“Then I certainly don’t. But if you think that Mac will take any notice of what I—or you—think, you should know better. The man’s a human mule. Particularly when one of his pet ideas is at stake.”
“Jeanie, he listens to you more than anyone.”
This, while true, was hardly relevant. But something else was going on here.
“Professor, I understand that money is tight at the Institute—it’s tight everywhere with today’s economic conditions. Fazool’s money must be a great temptation. But money or no money, won’t Mac need the use of Institute equipment to perform his project?”
“Assuredly. What he has in mind would be impossible without it.”
“Then if you’re so worried about this, why not just say no? Fazool’s a powerful man, and I’m sure he has lots of influence. But he can’t force the Institute to do whatever he fancies, even with Mac’s blessing.”
Limperis eyed me thoughtfully. He’s as sharp as they come, and normally he’s inscrutable. This time, though, I could read what was in his mind. It was, How much can I afford to tell her?
“It’s not quite that simple, Jeanie,” he said at last. “McAndrew views his expedition as a research activity, but not everyone sees it that way. Others at the Institute believe that we may be in sight of a new and inexhaustible source of free energy.”
“There can’t be any such thing,” I began, then paused. Others at the Institute. I suspected that I was talking to one of them. “Can there?”
He coughed. “Well, there might be. There just might. And as you can imagine, it’s very difficult for the Institute to say no to a project that won’t ne
ed a penny of our funds and holds out even the remotest chance of unlimited free energy. I’m in a spot, Jeanie.”
It was dawning on me. Limperis didn’t want me to talk to Mac. We both knew that was a waste of breath. He wanted me directly involved, because he was worried about McAndrew’s judgment and possible fate. And, of course, if Limperis was worried he thought I should be doubly so.
As I was. He had me, and he knew it. I was about to be sucked in. Forget my holiday and Fat Man’s Run, I must fly out and talk to McAndrew. As I said, some people never learn.
Limperis didn’t tell me what McAndrew’s infinite energy scheme was all about. Better, he said, that it should come from McAndrew himself. That was his way of ensuring that I would head out to the Penrose Institute as soon as possible to clear up the mystery.
The Institute had settled into one of its rarer research locations, down near the Vulcan Nexus. Although an excellent site for solar observation, it is one of the places in the solar system that I least like to visit. It is perfectly safe—they tell you—but the Sun is only two million kilometers away and occupies half the sky. An unprotected human exposed to the intense flux of radiation will fry and die in ten seconds.
That sort of risk means nothing to a man who has spent a large fraction of his life thirty meters from a kernel, a shielded Kerr-Newman black hole. I found McAndrew staring through a set of specially designed optical filters at the naked solar surface. Prominences a million kilometers long sprang out at him—at least, they sprang out at me.
The greatest theorist since Einstein and the greatest combination of experimenter and theorist since Newton was dressed in dirty long johns. His thinning hair straggled down over his face. He was in his bare feet, and he was sitting cracking his toe joints in a way that I found both infuriating and disgusting.
The Compleat McAndrew Page 40