I do not recall having met an educated person who claims to know less about contemporary physics than I do. Nevertheless, it has been my contention that as physicians living in the early part of the second half of the twentieth century we have very strong obligations to understand as much as we can of the world we live in. Perhaps if this could be done on a large scale events might be bent somewhat to wise purposes rather than just letting them happen. The introduction of the uncertainty principle, for which Heisenberg received the Nobel Prize, may be of some comfort in its oversimplified form as applied to research in biology. As I understand it, his essential belief is that by the very act of measuring a variable factor is introduced which disqualifies the evidence by virtue of altering the thing measured. Certainly, in clinical investigation and in biology
I do not recall having met an educated person who claims to know less about contemporary physics than I do. Nevertheless, it has been my contention that as physicians living in the early part of the second half of the twentieth century we have very strong obligations to understand as much as we can of the world we live in. Perhaps if this could be done on a large scale events might be bent somewhat to wise purposes rather than just letting them happen. The introduction of the uncertainty principle, for which Heisenberg received the Nobel Prize, may be of some comfort in its oversimplified form as applied to research in biology. As I understand it, his essential belief is that by the very act of measuring a variable factor is introduced which disqualifies the evidence by virtue of altering the thing measured. Certainly, in clinical investigation and in biology
The role of the observer in biologic research is complicated but not bizarre: he or she simply observes, describes, interprets, maybe once in a while emits a hoarse shout, but that is that; the act of observing does not alter fundamental aspects of the things observed, or anyway isn't supposed to.It is very different in modern physics. The uncertainty principle doesn't mean that the observer necessarily destroys the precise momentum, or shifts the particle, in the act of observing, although these things happen. It is a more profound effect. The observer and his apparatus create the reality to be . . .
In a recent number of Blackfriars (July, 1949) Dr A. W. Gledhill has discussed very competently some aspects of the statistical method as used in modern physics. He has tried to show there ‘that modern physical theory does not contradict the principle of causality’. Having made a study of this subject over quite a number of years, the writer, while agreeing with some of Dr Gledhill’s conclusions, feels nevertheless that there are a few points which have not been covered as adequately as the importance of the subject for modern philosophy seems to warrant. In order to understand the controversy about the validity or non-validity of the principle of causality, which has been initiated by Heisenberg’s uncertainty principle, it is necessary to realise, first of all, that when a physicist speaks about causality, he usually does not mean the same thing as a scholastic philosopher. In scholastic philosophy one distinguishes different kinds of causes, such as the material, the efficient, the final, as well as the formal and exemplary causes. The classical physicist, on the other hand, since the time of Galileo, admits only efficient causes. Let us therefore give a brief sketch of the development of this concept of scientific causality and show the reasons for this limitation. The purpose of a scientific theory is the prediction of events among the natural objects which form the field of enquiry of the particular science concerned. Evidently, the more certain the prediction, the better the theory on which it is based.
We have now concluded our summary of the findings of modern physics, and may turn to consider how these findings affect the practical problems of philosophy and of everyday life. But let us first recapitulate the conclusions we have reached in our scientific discussion. Recapitulation Because we are human beings and not mere animals, we try to discover as much as we can about the world in which our lives are cast. We have seen that there is only one method of gaining such knowledge—the method of science, which consists in a direct questioning of nature by observation and experiment. The first thing we learn from such questioning is that the world is rational; its happenings are not determined by caprice but by law. There exists what we have called a ‘pattern of events’, and the primary aim of physical science is the discovery of this pattern. This, as we have seen, will be capable of description only in mathematical terms. The new quantum theory explained in the preceding chapter has provided a mathematical description of the pattern of events which is believed to be complete and perfect. For it enables us—in principle at least—to predict every possible phenomenon of physics, and not one of its predictions has so far proved to be wrong. In a sense, then, we might say that theoretical physics has achieved the main purpose of its being, and that nothing remains but to work out the details.
In 1903 the physicist Albert Michelson made an astonishing pronouncement. Confident of the advances made by the great physicists of the Victorian era, such as Lord Kelvin, James Clark Maxwell and Thomas Edison, he declared that ‘the most important fundamental laws and facts of physical science have all been discovered, and these are now so firmly established that the possibility of their ever being supplemented in consequence of new discoveries is exceedingly remote’.1 In so doing he followed what appeared to be a long-established tradition that eminent physicists should make bold and far-reaching statements on the nature of the universe and its physical laws.2 Unfortunately, Michelson’s timing could not be worse as early twentieth-century physicists were about to make a string of discoveries that would fundamentally alter our perceptions of the universe. The world as Michelson understood it was about to be turned on its head by the work of three men: Max Planck, Albert Einstein and Ernest Rutherford. The first, Planck, was a respected German physicist who had done work on entropy, but had done little to distinguish himself. Then in 1900 he developed his ‘quantum theory’ which posited that energy did not flow as a stream or wave as had been imagined before, but rather was carried by packets or quanta. This seemingly simple, yet deceptively complex, thesis was to have a profound effect upon our understanding of the physical universe. Planck’s thesis proved to be the foundation for the modern discipline of quantum physics, a discipline that first came to the attention of the wider public when in 1905 a young Swiss patents clerk called Albert Einstein wrote five papers for the Annalen der Physik. Three of these papers are widely accepted to be among the best in the history of physics and examined photoelectric effects by applying Planck’s new quantum theory, Brownian Motion and a ‘Special Theory of Relativity’. As Bill Bryson notes in his Short History of Nearly Everything, ‘the first won its author a Nobel Prize and explained the nature of light (and also helped make television possible among other things). The Second provided proof that atoms do indeed exist – a fact that had surprisingly, been in some dispute. The third merely changed the world’.3 Thus within two years of Michelson’s pronouncement much of our understanding of the physical universe had been turned on its head by this new development; but for Michelson worse was to follow. In 1895, a young South African named Ernest Rutherford had won a scholarship to the world famous Cavendish Laboratory at the University of Cambridge. By 1911, Rutherford had become obsessed with the nature of atoms, the basic building blocks that form the constituent parts of the universe. That year he proposed his ‘theory of atomic nuclei’, which suggested that all the positive charge and most of the mass of an atom must be contained in a tiny nucleus at the atom’s centre, with the negatively charged electrons ‘in orbit’ about this nucleus. To prove his thesis Rutherford had to ‘split’ the atom to prove that he could release matter from this nucleus, something which he finally succeeded in doing in 1919 when he showed that by firing alpha-particles into nitrogen gas a small amount of hydrogen could be produced. In so doing he also established that energy could be released from the nucleus of an atom, thereby proving an essential part of Albert Einstein’s Special Theory of Relativity: the unification of energy and mass, usually represented by the famous equation E=mc2.4 With Rutherford providing the link between quantum theory and nuclear physics the Newtonian view of the universe, which was at the heart of Michelson’s beliefs, had been rewritten in less that 20 years.
The turn of the XXth century witnessed a revolution in physics comparable to Isaac Newton’s discovery of the universal laws of mechanics and of gravitation three centuries earlier. The world required to be described in novel terms, as the immutable, deterministic view of our familiar universe had given way to a new world picture, one which featured chance, flux, and an incessant upsurge of waves of matter. Such a worldview was so radically new and counterintuitive that it gave rise to strong debates, to the effect that Albert Einstein himself tried to oppose it on the grounds that “God does not play dice”. In spite of the intense debates that accompanied its emergence, quantum mechanics quickly proved an incredibly efficacious new tool to understand and to predict a wide array of new phenomena. It was so successful that in no time it broke free from the environment of research labs to become part of daily life, making it possible, for example, to understand why some materials were conductors, while others were insulators. Along with it, came, too, the discovery of transistors, on which much of modern electronics rests. It also led to understand how novel materials known as superconductors allow the transport of electricity with no loss, thus paving the way for new developments in the fields of medical imagery or energy distribution. Other aspects of the quantum theory led to the development of atomic clocks of astounding accuracy, which would be wrong by no more than fifteen seconds, had they been set at the beginning of the universe. A hundred years later, at the turn of the XXIst century, Quantum mechanics has lost none of its astounding power. Contemporary research has undertaken the task of exploring its less immediately perceptible aspects. Groundbreaking developments have ensued, such as the teleportation of grains of light or the possibility, once predicted by the great physicist Richard Feynman, to build, one day, novel computers which, unlike the ones we are familiar with today, will be able to process innumerable numbers of operations in parallel. The Wright Colloquium will be for us the occasion to explore, in the company of five internationallyknown specialists in the field, some of the fascinating aspects of quantum mechanics. We will appraise how efficiently quantum physics can describe our world, and confront its limitation when it is faced with the infinitely small (in relation to recent experiments carried out at the CERN) as with the incommensurably large scale of sidereal spaces. We will appreciate the extent to which quantum physics already has impacted our everyday lives, and evoke the way in which novel fields such as quantum computers and quantum information will entail profound changes in the future. The quantum adventure has only just begun! Monday 15 November 2010 - 18h30 Jochen Mannhart Center for Electronic Correlations and Magnetism, University of Augsburg, Germany Quantum Physics on the Scale of Daily Life Tuesday 16 November 2010 - 18h30 Wolfgang Ketterle Nobel Laureate 2001 (Physics), Department of Physics, Massachusetts Institute of Technology, Cambridge, U.S.A. When freezing cold is not cold enough New forms of matter close to absolute zero temperature Wednesday 17 November 2010 - 18h30 David Gross Nobel Laureate 2004 (Physics), Kavli Institute for Theoretical Physics, University of California, Santa-Barbara, U.S.A. Quantum Mechanics of the Very, Very Small and the Very, Very Large Thursday 18 November 2010 - 18h30 Alain Aspect CNRS senior scientist and Professor Institut d'Optique and Ecole Polytechnique Palaiseau, France. From Einstein’s intuition to quantum bits: a new quantum age? Vendredi 19 novembre 2010 - 18h30 Rainer Blatt Institute of Quantum Optics and Quantum Information, Austrian Academy of Sciences and University of Innsbruck, Austria The Quantum Way of Doing Computations