Borderlands of Science

by Charles Sheffield

  His answer to that question is, yes, such a quantum world is required. To see the direction of his argument, it is necessary to revisit what was said in Chapter 2 about quantum theory.

  In the quantum 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." This is a well-known, if not well-understood, element of standard quantum theory.

  What Penrose suggests is that the human brain is a kind of quantum device. In particular, the same processes that collapse the quantum mechanical wave function in subatomic 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 cell known as microtubules. A microtubule is a tiny tube, with an outer diameter of about 25 nanometers and an inner diameter of 14 nanometers. The tube is made up 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. Like the Wizard of Oz, the theory was more impressive when it was hidden away behind the curtain.

  My views, however, are not the issue. Is Penrose wrong, destined to be remembered as a scientific heretic? Or is he right, and a true prophet?

  It is too soon to say. But if he proves to be right, his ideas will produce a huge change in our conceptions of physics and its relation to consciousness. More than that, the long-term future of computer design will become incredibly difficult.

  With the latter point in mind, we might paraphrase Bertrand Russell. He said of Wittgenstein's theories, as we can say of Penrose's: "Whether they are true or not, I do not know; I devoutly hope that they are not, as they make mathematics and logic almost incredibly difficult."

  Meanwhile, I am waiting for a story to appear making use of Penrose's extraordinary claim that we are controlled by quantum processes within the brain's microtubules.

  13.6 Diseases from space. In the late 1970s, two respected scientists proposed an interesting and radical new theory (Hoyle and Wickramasinghe, 1977): Certain diseases are often not carried from one person to another by the usually accepted methods, sometimes mutating as they go to become other strains of the same infection; instead, the diseases arrive on Earth from space, and the observed variations arise there.

  In the words of Fred Hoyle and Chandra Wickramasinghe (1977), the joint proposers of the theory:

  "In Diseases from Space we shall be presenting arguments and facts which support the idea that the viruses and bacteria responsible for the infectious diseases of plants and animals arrive at the Earth from space."

  They support their contention on biochemical grounds, and also from statistical evidence on the spread of influenza in Britain.

  The same two workers also suggest that life itself did not develop on Earth. It was borne here, as viruses and bacteria.

  Again in their words: "Furthermore, we shall argue that apart from their harmful effect, these same viruses and bacteria have been responsible in the past for the origin and evolution of life on the Earth. In our view, all aspects of the basic biochemistry of life come from outside the Earth."

  Where, then, did life originally develop? Hoyle and Wickramasinghe give their answer: It arose naturally in that great spherical collection of comets known as the Oort Cloud, which orbits far beyond the observable solar system. They argue that conditions for the spontaneous generation of life were far more favorable there than they were on Earth, three and a half billion years ago when life first appeared here.

  This idea is not totally original with them. Early this century, the Swedish chemist Svante August Arrhenius proposed that life is widespread in the universe, being constantly diffused from one world to the next in the form of spores. The spores travel freely through space, now and again reaching and seeding some new habitable world (Arrhenius, 1907). Hoyle and Wickramasinghe, while not accepting this panspermia concept totally, and substituting viruses and bacteria for Arrhenius's spores, do claim that life was brought to Earth in a similar fashion.

  Hoyle and Wickramasinghe also deny that many epidemics of infectious disease are spread by person-to-person contact or through intermediate carriers (such as lice and mosquitoes). They claim that influenza, bubonic plague, the common cold, and smallpox all originate in the fall of clouds of infecting spores (bacteria or viruses) from space, and are mainly spread by incidence from the air.

  This sounds, on the face of it, somewhat unlikely. No one has ever observed a virus or a bacterium present in space, or arriving from space. However, the reaction of the medical community went far beyond polite skepticism. The new idea was ignored or vilified as preposterous, and it was treated as a true scientific heresy.

  Why was the reaction of the medical establishment so strong?

  First, there was a question of qualifications. Not as scientists, where the credentials of both proposers are impeccable. Hoyle is one of the world's great astrophysicists, a man who has made profound contributions to the field, and Wickramasinghe is a well-known professor. However, neither Hoyle nor Wickramasinghe is a physician or a microbiologist. They were astronomers, operating far outside their own territory.

  Second, the presently accepted idea for disease transmission was itself once a scientific heresy. It took three hundred years for the notion that tiny organisms can invade the human body and ca
use infections to change from wild surmise to scientific dogma. Such a theory, so hard-won, is not readily abandoned. Thus, in 1546, Girolamo Fracastoro proposed a germ theory of disease. In his book De Contagione, he suggested three modes of transmission: by direct contact, indirectly through such things as clothing, and through the air. He was generally ignored, if not actively ridiculed.

  The situation changed only in the late eighteenth century, when scientists were able to verify the existence of bacteria by direct observation with the microscope. And it was not for almost a hundred years more, until the second half of the nineteenth century, that Louis Pasteur and Robert Koch put the matter beyond question when they isolated the specific bacterial agents that cause anthrax, rabies, cholera, and tuberculosis, and used inoculation to protect against several of them.

  The modern picture of disease transmission then appeared to be complete, and it is not far from Fracastoro's original ideas. Contagious diseases spread from person to person. Some call for personal contact, like syphilis. Some can be transmitted through the air, like the common cold. Some diseases, like malaria, require the action of an intermediate organism such as a mosquito; and some, like trichinosis, can be transmitted by the ingestion of infected food. However, all communicable diseases have one thing in common: they originate somewhere on the surface of the Earth, and they are carried by terrestrial organisms.

  This leads at once to the third and perhaps the biggest objection to Hoyle and Wickramasinghe's theory: there is overwhelming direct evidence for the conventional means of disease transmission. Even if the new theory were to prove right in part, it cannot be the whole story. Thus, the rapid spread of bubonic plague through Europe in the fourteenth century, and the almost instantaneous and devastating effects of smallpox on native American Indians when it was brought by Europeans in the early sixteenth century, owe nothing at all to space-borne spores. The attacks were too sudden and the timing too coincidental. These diseases ran riot in populations which had no previous exposure to them, and therefore lacked protective antibodies against them.

  Ultimately, then, the main argument against the theory offered by Hoyle and Wickramasinghe may not be that it is ridiculous, or biologically unfounded, or in some way impossible. It is that it is not necessary, since the established notions of disease propagation seem quite sufficient to explain everything that we see, and are required for that explanation.

  Until today's theories prove inadequate, or there is better evidence for the new theory, the idea that diseases arrive from space will remain what it is today: a scientific heresy.

  13.7 Cold fusion. On March 23, 1989, a press conference was held at the University of Utah. The organizers of the conference stated that they had managed to initiate and sustain a nuclear fusion reaction. That announcement astonished the world, for several unrelated reasons.

  First, the use of a press conference is not the normal method for announcement of a scientific discovery. Scientists have a well-defined procedure for doing this: the discovery is described in enough detail for others to know what has been done, and to begin the process of verification; in the case of an important discovery, where precedent may be important, a brief note is sent to the appropriate scientific journal and preprints are sent to professional colleagues. Today, the preprint often takes the form of an e-mail letter. Scientists do not choose a press conference as the appropriate mechanism to reveal their discoveries. Those discoveries do not, as this one did, take over newspaper headlines around the world and lead to wild speculation in certain metals.

  The second reason for astonishment was the nature of the claimed discovery itself. Nuclear fusion is well-known to science. The fusion of hydrogen to helium is the main process that allows the sun and stars to shine. Here on Earth, nuclear fusion makes possible the hydrogen bomb. Large experimental facilities in this country and elsewhere have spent billions of dollars over the past forty years, trying to tame the violent fusion of the hydrogen bomb to permit a controlled release of energy. Nuclear fusion looks like the Holy Grail of endless and clean energy production, but the experimental equipment needed is large and complex, and employs temperatures of tens or hundreds of millions of degrees—hotter than the center of the sun.

  By contrast, the nuclear fusion described in the Utah press conference takes place at room temperature—"cold" fusion—and calls for only the simplest of means. All that is needed is a beaker of "heavy" water and a palladium electrode. Heavy water is water in which the normal hydrogen atoms have been replaced by deuterium, a rare but well-known heavier form of hydrogen (see Chapter 5). Heavy water is naturally present in ordinary water, at a concentration of about one part in six thousand. Palladium is a steely-white metal, also rather rare but well-known and widely available.

  The final surprise in the Utah announcement was the identity of the two scientists given credit for the discovery. Martin Fleischmann had a distinguished career in England before retiring as an emeritus professor from the University of Southampton and beginning the work in Utah. He is a Fellow of Britain's most prestigious scientific group, the Royal Society, and has been described by colleagues as "more innovative than any other electrochemist in the world." Stanley Pons had been a student under Fleischmann at Southampton, before becoming the prolifically productive head of the University of Utah chemistry department. Both men thus had excellent credentials—as chemists. Nuclear fusion, however, is a problem calling for knowledge not of chemistry but of physics. It requires an understanding of the processes by which the nuclei of atoms can be combined.

  Physicists as a group often do not have the highest regard for chemistry, which they consider as messy and unsystematic and more like cooking than science. It was, therefore, unusually satisfying to chemists and galling to physicists when Fleischmann and Pons, using the simplest of means, seemed to have made the whole expensive business of conventional nuclear fusion experiment, as performed by physicists, seem irrelevant.

  Fleischmann and Pons had an explanation for the way their results had been achieved. At first sight that explanation seemed very plausible. It has been known for generations that palladium has a high natural affinity for hydrogen. A palladium rod, placed in a hydrogen atmosphere, will absorb up to nine hundred times its own volume of hydrogen. It will do the same thing if heavy hydrogen is used in place of ordinary hydrogen. According to Fleischmann and Pons, the palladium electrode would absorb heavy hydrogen from the heavy water, and within the palladium the heavy hydrogen nuclei would be so close to each other that some of them would fuse. The result would be helium and heat. Neutrons, an elementary particle present in the heavy hydrogen, would be released as a by-product. Fleischmann and Pons reported seeing significant heat, more than could possibly be produced by chemical processes, and a small number of neutrons. All of this happened at room temperature, in a beaker no bigger than a peanut butter jar.

  The press conference did not give details of the process, so other groups had trouble at first either confirming or denying the claimed results. It took several months before a coherent picture emerged. When the dust settled, the verdict was not in favor of Fleischmann and Pons. Some other groups observed a few, a very few, neutrons, barely more than the normal background level. Others reported excess heat, but no neutrons, and again it was nowhere near what had been claimed by the Utah group.

  Why didn't Fleischmann and Pons seek confirmation from those other groups, before they made their announcement? To some extent, they did, and they were still in the process of doing so. However, great pressure to make that announcement prematurely, and to do it through a press conference, came not from the two chemists but from officials at the University of Utah. The university administrators could see an enormous profit potential if the cold fusion claims held up. That potential would only be realized if patents were granted and the Utah claim to precedence recognized. It must have seemed like a good bet, at least to the officials: the reputation of two professional chemists, against possible multiple billions of dollars of g
ain for the university.

  Today, the bet appears to be over. Fleischmann and Pons were the losers. They still insist that their original results are correct, and continue their research not in Utah but in France, with private funding. However, few other reputable scientists believe they will find anything valuable.

  Even at the very beginning, there were basic physical reasons to discount the "cold fusion" claim. The number of neutrons observed was far too small, by a factor of billions, to be consistent with the claimed heat production. Real fusion would produce huge numbers of neutrons, enough to be fatal to anyone in the same room as the beaker with its palladium electrode.

  Many people continue to believe ardently in cold fusion. I do not, though some new phenomenon—not fusion—may be there. And I must say, I feel a great deal of sympathy for Pons and Fleischmann. They were pushed by university administrators into making the premature announcement of results.

  Had they followed a more conventional route, the results might have been very different. The obvious parallel is in the area of high temperature superconductivity. In 1986, Müller and Bednorz produced the first ceramic superconductors. Such things were "impossible" according to conventional theories. But when experiment and theory disagree, theory must change. Müller and Bednorz won the 1987 Nobel Prize for physics.

  Were Pons and Fleischmann robbed of similar fame by the actions of others? Possibly. However, martyrdom is not enough to make a theory correct. Today, cold fusion remains as scientific heresy.

  13.8 No Big Bang. The standard model of cosmology sees the Universe as beginning in a primordial, highly condensed fireball that has been expanding ever since. Such a model explains the recession of the galaxies, the 2.7 Kelvin microwave background radiation, and the relative abundance of the elements, particularly hydrogen and helium. Each of these independent phenomena seems to provide powerful observational evidence.