Synopsis
What do the Hubble Telescope, Buffalo Bill and the Spanish Inquisition have in common, and how is the answer found in a fast food chain? Continuing the journey he began in "The Pinball Effect", James Burke shows how unrelated ideas and innovations bounce off each other, spinning a web of knowledge.
Extrait
Chapter 1
Feedback
This book takes a journey across the vast, interconnected web of knowledge to offer a glimpse of what a learning experience might be like in the twenty-first century once we have solved the problem of information overload.
In the past when technology generated information overload the contemporary reaction was much the same as it is today. On the first appearance of paper in the medieval West, the English bishop Samson of St. Alban's complained that because paper would be cheaper than animal-skin parchment people would use paper to write too many words of too little value, and since paper was not as durable as parchment, paper-based knowledge would in the long run decay and be lost. When the printing press was developed in the fifteenth century it was said that printed books would make reading and writing "the infatuation of people who have no business reading and writing." Samuel Morse's development of the telegraph promised to link places as far apart as Maine and Texas, triggering the reaction: "What have Maine and Texas to say to each other?" The twentieth-century proliferation of television channels has led to concerns about "dumbing-down."
The past perception that new information technologies would have a destabilizing social effect led to the imposition of controls on their use. Only a few ancient Egyptian administrators were permitted to learn the skills of penmanship. Medieval European paper manufacture was strictly licensed. The output of sixteenth-century printing presses was subject to official censorship by both church and state. The new seventeenth-century libraries were not open to the public. Nineteenth-century European telegraphs and telephones came under the control of government ministries.
The problem of past information overload has generally been of concern only to a small number of literate administrators and their semiliterate masters. In contrast, twenty-first-century petabyte laptops and virtually free access to the Internet may bring destabilizing effects of information overload that will operate on a scale and at a rate well beyond anything that has happened before. In the next few decades hundreds of millions of new users will have no experience in searching the immense amount of available data and very little training in what to do with it. Information abundance will stress society in ways for which it has not been prepared and damage centralized social systems designed to function in a nineteenth-century world.
Part of the answer to the problem may be an information-filtering system customized to suit the individual. The most promising of the systems now being developed will guide users through the complex and exciting world of information without their getting lost. This book provides an opportunity for the reader to take a practice run on such a journey. The journey (the book) begins and ends with the invention of the guidance system itself -- the semi-intelligent agent.
There are several types of agent in existence acting like personal secretaries in a variety of simple ways: filtering genuine e-mail from spam, running a diary, paying bills and selecting entertainment. In the near future agents will organize and conduct almost every aspect of the individual's life. Above all they will journey across the knowledge webs to retrieve information, then process and present it in ways customized to suit the user. In time they will act on behalf of their user because they will have learned his or her preferences by learning from the user's daily requirements.
In the search to develop semi-intelligent agents, one of the most promising systems (and the one which starts this journey) may be the neural network. Such a network consists of a number of cells each reacting to signals from a number of other cells that in turn fire their signals in reaction to input from yet other cells. If input signals cause one cell to fire more frequently than others, its input to the next cell in the series will be given greater weighting. Since cells are programmed to react preferentially to input from cells that fire frequently rather than from those that fire rarely, the system "learns" from experience. This is thought to be similar to the way learning operates in the human brain, where the repetition of a signal generated in response to a specific experience can cause enlargement in the brain cell's synapses.
The synapse is the part of the cell that releases transmitter chemicals that cross the gap to the next cell. If sufficient chemicals arrive on the other side, they generate an impulse. If enough of these signals are generated in the target cell, they cause its synapses to release chemicals in turn, and "pass the message on." A cell with larger synapses, releasing larger amounts of chemical, is therefore more likely to cause another cell to fire. Networks of such frequently firing cells may constitute the building blocks of memory.
This theory of neuronal interaction was first proposed in 1943 by two American researchers, Walter Pitts and Warren McCulloch, who also suggested that such a feedback process might result in purposive behavior when linking the senses with the brain and muscles if the result of the interaction were to cause the muscles to act to reduce the difference between a condition in the real world as perceived by the senses and the condition as desired by the brain.
Pitts and McCulloch belonged to a small group of researchers calling itself the "Teleological Society," another of whose members was the man who invented the name for this neural feedback process. He was Norbert Wiener, and he was the first to see the way in which feedback might work in a machine, during his research on antiaircraft artillery systems during World War II. Wiener was a rotund, irascible, cigar-chomping MIT professor of math who prowled what he described as the "frontier areas" between the scientific disciplines. Between biology and engineering wiener developed a new discipline to deal with feedback processes. He called the new discipline "cybernetics." Wiener recognized that feedback devices are information-processing systems receiving information and acting upon it. When applied to the brain this new information-oriented view was a fundamental shift away from the entirely biological paradigm that had ruled neurophysiology since Freud, and it was to affect all artificial-intelligence work from then on.
Wiener first applied his feedback theory early in World War II, when he and a young engineer named Julian Bigelow were asked to improve the artillery hit rate. At the beginning of the war the problem facing antiaircraft gunners was that as the speed of targets increased (thanks to advances in engine and airframe technology) it became necessary to be able to fire a shell some distance ahead of a fast-moving target in order to hit it. Automating this process involved a large number of variables: wind, temperature, humidity, gunpowder charge, length of gun barrel, speed and height of target, and many others. Wiener used continuous input from radar tracking systems to establish the recent path of the target and use that path to predict what the target's likely position would be in the immediate future. This information would then be fed to the gun-moving mechanisms so that aiming-off was continually updated.
The system had its most outstanding successes in 1944; when British and American gunners shot down German flying bombs with fewer than one hundred rounds per hit. This was an extraordinary advance over previous performance, estimated at one hit per twenty-five hundred rounds. In 1944, during the last four weeks of German V-1 missile attacks on England, the success rate improved dramatically. In-the first week, 24 percent of targets were destroyed; in the second, 46 percent; in the third, 67 percent; and in the fourth, 79 percent. The last day on which a large number of V-1s were launched at Britain, 104 of the missiles were detected by early-warning radar, but only four reached London. Antiaircraft artillery destroyed sixty-eight of them.
Early in his work on the artillery project Wiener had frequent discussions with a young physiologist named Arturo Rosenbleuth, who was interested in human feedback mechanisms that act to ensure precision in bodily movement. For the previous fifteen years Rosenbleuth had worked closely with Walter Cannon, professor of physiology at Harvard. Earlier in the century Cannon had invented the barium meal, which was opaque to X-rays. When ingested by a goose the barium revealed the peristaltic waves that occurred in the bird's stomach when it was hungry. Cannon observed that hunger seemed to precipitate the onset of these waves. He then observed that when a hungry animal was frightened the waves stopped.
This led to Cannon's ground-breaking studies, of the physical effects of emotion. He discovered that when an animal was disturbed its sympathetic nervous system secreted into the bloodstream a chemical that Cannon named "sympathin." This chemical counteracted the effects of the disturbance and returned the animal's body systems to a state of balance. Cannon named the balancing process "homeostasis." In 1915 Cannon discovered that the principal body changes affected by the sympathetic system were those involved in fight, sexual activity or flight. In such situations sugar flowed from the liver to provide emergency energy and blood shifted from the abdomen to the heart, lungs and limbs. If the body were wounded, blood clotting occurred more rapidly than usual. In 1932 Cannon published a full-scale account of his research titled The Wisdom of the Body.
What had initially triggered cannon's interest in homeostatic mechanisms was the work of the man to whom Cannon dedicated the French edition of his book. He was an unprepossessing but eminent French physiologist named Claude Bernard, who had started his working life as a pharmacist's assistant in Beaujolais, where his father owned a small vineyard. After being forced to give up his early schooling for lack of funds, Bernard took up writing plays. He produced first a comedy and then a five-act play, which he took to Paris in 1834 with the intention of making a career in the theater. Fortunately for the future health of humankind Bernard was introduced to an eminent theatrical critic, Saint-Marc Girardin, who read the play and advised Bernard to take up medicine.
At first Bernard planned to be a surgeon, but becoming dissatisfied with the general lack of physiological data he began to gather his own data by experimenting on animals. By 1839 his dexterity in dissection had brought him to the attention of the great physiologist François Magendie, who appointed him as assistant. One winter morning, in 1846 some rabbits were brought to Magendie's lab for dissection and Bernard noticed that their urine was clear and acidic. As every nineteenth-century French winemaker knew, the urine of rabbits is usually turbid and alkaline. Bernard realized that the rabbits had not been fed and theorized that since the urine of carnivores is clear, the hungry, herbivorous rabbits must have been living on their fat. When he fed grass to the rabbits their urine returned to its normal alkaline turbidity. He double-checked with an experiment on himself. After twenty-four hours subsisting only on potatoes, cauliflower, carrots, green peas, salad, and fruit, Bernard's own urine went turbid and alkaline. Bernard then starved the rabbits, fed them boiled beef and dissected them to find out what had happened. He saw a milklike substance (he took it to be emulsified fat) that had formed at the point where the rabbit's pancreatic juice was pouring into the stomach: There was clearly some link between the juice and the emulsification of the fats.
Two years later he discovered the glycogenic function of the liver, which injects glucose into the blood. It was this discovery thai led to Bernard's greatest contribution to the sum of human knowledge, because he saw that the function of the liver and the pancreas (and perhaps other systems, too) was to maintain the body's equilibrium. He summed up his research: "All the vital mechanisms; however varied they may be, have only one object, that of preserving constant the conditions of life in the inner environment." Follow-up research on the pancreas led an English researcher, William Bayliss, to coin the phrase that Cannon would use as his book title: "the wisdom of the body."
Not everybody was happy with Bernard's work, especially when he designed an oven in which to cook animals alive. An American doctor, Francis Donaldson, who attended Bernard's lectures in 1851, wrote: "It was curious to see walking about the amphitheater of the College of France dogs and rabbits, unconscious contributors to science, with five or six orifices in their bodies from which at a moment's warning, there could be produced any secretion of the body, including that of the several salivary glands, the stomach, the liver, and the pancreas."
Bernard was well aware of public opposition to vivisection but defended it: "The science of life is like a superb salon resplendent with light which one can enter only through a long and ghastly kitchen." Alas, Bernard's wife was unable to take the heat. After leaving him in 1869 she went in search of the antivivisection activists to whom she had been sending regular contributions.
She did not have far to go. In Paris a fanatical young vegetarian Englishwoman named Anna Kingsford, the owner of the Lady's Own Paper, had come to France to study medicine. Kingsford became well-known at the medical school for refusing to let her professors vivisect during the lessons she attended and for demonstrating against the practice. Kingsford's lecture halls were close to Bernard's labs, and she became so obsessed by his work that she set about directing all her energies toward killing him with thought waves. Bernard died only few weeks after she had begun to concentrate her mental energies on him, convincing her that she had been the instrument of divine will. Kingsford also claimed to have been responsible for the death of another vivisector, Paul Bert. However her efforts to do the same to Louis Pasteur failed.
Legislation to protect animals from ill treatment took a long time to reach the statute books, even in England, where the first such laws were passed. In 1800 the first bill to outlaw bull-baiting had ignominiously failed in its passage though the Houses of Parliament, opposed by George Canning (later prime minister), who claimed that bull-baiting "inspired courage and produced a nobleness of sentiment and elevation of mind....Putting a stop to bull-baiting was legislating against the spirit and genius of almost every country and age." However, in 1821 Dick Martin, MP for Galway, forced through a bill to protect horses and cattle against ill treatment. It was the first law of its kind in any country. In 1824 the Society for the Prevention of Cruelty to Animals was formed at the unfortunately named Old Slaughter Coffee House in London. The publication in 1859 of Darwin's Origin of Species seemed to strengthen the relationship between humans and animals and support the animal-defense argument. In 1876 the Victoria Street Society against Vivisection was formed with Lord Shaftesbury as chairman. The same year a bill was passed to prevent the vivisection of dogs, cats, mules, horses and asses. By the late nineteenth century the animal-defense movement had spread throughout the Western world and given birth to hundreds of local groups known as Humane Societies, in spite of the fact that the name more properly belonged to earlier humanitarian work of an entirely different nature.
The Royal Hu...
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