Nr 01 . 8 janvier 2010
Table des matières
L’auteur présente son point de vue personnel, selon lequel le problème de l’unification de la relativité générale et des théories quantiques réside dans leur grande différence de caractère. La relativité est une théorie classique offrant une description littérale de la réalité alors que toutes les théories quantiques sont abstraites et n’offrent qu’un moyen de faire des prédictions. L’auteur considère que le temps pourrait être le problème le plus important et examine la proposition de Julian Barbour, selon lequel il n’existe pas. Il se livre à une conjecture spéculative relative à la notion de causalité non standard introduite pour la première fois par John G. Cramer, puis propose une extension de cette idée, en montrant comment elle pourrait conduire à une unification, à une meilleure compréhension du cerveau et du Big Bang.
The author presents his personal involvement with cosmology as a scientific artist. He gives an autobiographical summary of his life, starting from his childhood interests in astronomy and constructivism through to his abandoning a possible career in physics to become a kinetic artist. He describes in details his work with kinetic sculpture, in particular, his many sculptures based on waves, the Timeless Universe and Abstract Cosmology Installations. This last work was shown at the Reina Sofia Museum, in Madrid in 2008 as part of the Souls and Machines Exhibition.
The author presents his personal view that the problem of unification of general relativity and quantum theories lies in their very different character. Relativity is a classical theory that provides a literal description of reality, whereas as all quantum theories are abstract and provide only a means of making predictions. The author identifies time as perhaps the single most important problem and discusses Julian Barbour’s proposal that in does not exist. The author presents a speculative conjecture concerning non standard causality first introduced by John G Cramer and then proposes his own extension to this idea, showing how it might lead to unification, a better understanding of the mind and the Big Bang.
Scientists and artists are I believe more similar than people realise. They are both passionate about their work and prepared to work extraordinarily hard in pursuit of an idea. These ideas do not exist in a vacuum; they exist in relation to an existing body of work. Some individuals will add to that body of work but for those that are most daring their own work will challenge and may seek to overthrow our most basic ideas.
My own first inclination was to become a cosmologist. At that time I was a precocious teenager and cosmology was undergoing a transformation, as a great debate within the subject was to see the Big Bang theory rise to ascendancy and become the new orthodoxy. The evidence gathered in favour of the Big Bang was strong and its contender Steady State had clearly lost. I was horrified, as it looked to me like the ugliest and most illogical of ideas had won. I knew that if I was to become a cosmologist I would I have to do battle with the new champion. A singe day was to change my life and I moved away from the subject. It was while an undergraduate studying physics and mathematics that I visited a great exhibition of kinetics at the Hayward Gallery in London in 1970. The show was brilliant and of all the great work I saw there, the art of Nicholas Schoffer I found most inspiring of all. I changed direction and became an artist but I never lost interest in cosmology and continue to watch with keen interest from the sidelines.
More than a generation later the Big Bang still rules the roost but it has never fully resolved those logical problems. It is based on ideas that appear impossible to ever substantiate by experiment. Worse still there is no agreed physical theory that can explain the extraordinary conditions that must have existed in the first instance of the universe. The Big Bang has forced physicists to search harder and harder to find a theory that can describe that mysterious moment of creation and the brief period afterwards known as the Planck Epoch. To do this they must unify general relativity and quantum mechanics. Physicists have shown immense determination and imagination in tackling the problem and in the process invented some formidable new mathematics, but there is no sign of them finding the long sort after unification.
During the decades physicists have worked on the problem of unification, astronomers have added two further enigmas to the list, dark matter and dark energy. Even if physicists are successful in their goal of unifying general relativity with quantum theory, there is no knowing if this new understanding will include dark matter and energy. The goal of unification of all physical knowledge may well remain beyond reach and philosophically I am quite at ease with the idea that we can never find an ultimate theory. I find the idea of finding such a final theory disturbing.
I have been slow in returning to this subject and along the way picked up pieces of the puzzle. These include my own art work and my puzzlement and frustrations with some ideas in physics. My background is first I studied physics, and subsequently art. Initially I pursued my art without reference to physics but in recent years I have found the two coming together and myself thinking more about the same problems in physics that fascinated me in my youth. Here I make a most immodest proposal: a partial resolution.
I propose the key lies with time. The English physicist Julian Barbour takes the view that time does not exist. His idea reaches beyond scientific cosmology; it has philosophical, experiential and psychological qualities. I suspect the problem maybe deeper still and that neither time or space or spacetime exist. They are all products of some deeper ‘stuff’ that underlies reality, but eludes our comprehension. I will explore one possible consequence of this: I will show that the widely held view that if we allow the future to influence the present; this must lead to logical contradiction to be a fallacy. By applying certain constraints on this influence; the future can influence the present in an entirely logically consistent way. What I cannot show is a definite physical mechanism of how this influence might work. Before embarking on this speculation I shall begin by describing some of my artwork and how this relates to the question of unification.
My Work: I am a Scientific Artist
My earliest interest in life was outer space, growing up as a child at the beginning of the space age, the first exciting piece of news I remember understanding was that the Russians had launched Sputnik. This stimulated my childhood interest in space. Space travel and the idea of exploring space fascinated me. From a young age I was intrigued by how things work and had a gift for constructing and making. I dreamt of building my own space ship and I showed great ingenuity in my play, making endless fantasy spaceships and other projects. The materials I used could be almost anything: apart from toys I found value in parts salvaged from family thrown off broken clocks, radios, any other electrical gadget or something with moving parts. I reassembled them into my own « inventions ». Whether playing indoors with small bits and pieces that I collected in cardboard boxes or out in our large garden playing with a collection of pipes and planks and remains of materials left by builders and other workmen, I was always busy assembling them into something I would have called a « contraption ». In these unusual play activities lay the personal discovery of something like constructivism.
I was an instinctive sculptor but I did not yet realize it. A game does not serve a practical purpose. It exists and engages the mind of the child. Neither does art, it exists in its own right. It is there to engage the minds of all who care about it; it does not have to serve another purpose. Very early on I discovered this trait in myself. While all around people were doing things for some reason that had been provided to them, I always found the reasons for myself and took a very independent path in what I did and thought. I was never an intentional rebel yet I found myself the one who did things differently.
Today I create kinetic art, art that changes with time, but there are no beginnings, no middles and no endings. There is a flow in which it all just exists. Each instant is not frozen; it contains the quality of flow. It is alive with the ever changing patterns and waves. The sculptures are moving, transparent, luminous and feel weightless.
I conceived the idea of light sculpture in the early 80s. At the time I had already been making things that could be described as light sculptures for ten years but I had not until then begun to conceptualize my activity. At that time various forms of 3D imaging had been developed as technical experiments in media. Perhaps the best known is holography. A hologram has the appearance of a magic window. You look through the window and see a scene complete with a perfect sense of depth, but there are some restrictions. Colour rendering is poor or non-existent and the choice of subject matter is limited as it is difficult to render objects except from pre-existing forms. Everything is still, there can be no motion, or at best a very limited range of stylized poses the scene can jump through. As a technical discovery, it caused considerable excitement, but as an artistic means of expression, it was soon recognised to be of limited value and became relegated to the status of a novelty. Another approach to 3D was through the use of stereoscopic imaging. This is much older and has existed since shortly after the invention of photography. By presenting the left and right eye with separate images each showing a view of a scene exactly as if the your eyes had been present at the time the photos are taken, our brains when presented with the pair of images can interpret them as if they were looking directly at the real scene, but there are some problems with this technique. Our eyes are used to refocusing on objects at different distances so that our impression of the scene shows us everything clearly even though we can only focus at one range at a time. In a stereo image, everything is presented at an arbitrary focal distance. The result can cause eye strain or destroy the impression of depth provided by the stereo, none the less the results are more adaptable than holography and it has found a niche as part of spectacular IMAX presentations, where the audience is asked to wear special glasses to view a 3D movie. Again it has failed to elicit wide interest as a serious artistic media, although it is currently in vogue amongst maker of special effects movies.
I asked myself: what are the distinguishing qualities that would define a truly satisfying 3D imaging system? I decided the first consideration was the way you view the subject should be exactly as if it were a real object. It should be visible with no frame or window that restricts viewing angles. It should stand free and be possible to walk all around it, view it from afar or move in close. These actions seem obvious but are the basic physical necessities that make it possible to contemplate a work like a sculpture. It is through the physical, visual and mental process that we can appreciate a work of art most thoroughly. All these technical media were restricting our freedom in ways that inhibit a truly free emotional response to the subject. This freedom to view the subject as if it were real is, I believe, the vital quality that was missing. There were several other less obvious things that I wanted to achieve and in so doing I happily went down a path that was no longer a search for a technical media with wide application, but instead became a very personal search for a new media with which to express myself. Thus was born the route of light sculpture.
Those other things were to do with the qualities of the work. Now quality can be used to mean good or bad, this is not the meaning I intend (although of course I would hope my work would be good). I mean quality like light or dark, like smooth or rough. I wanted to achieve works that had the feeling that they were made not of physical material, but made of light. They should feel immaterial and weightless. They needed to be transparent, so that we could see right through them and see every part from every direction, with nothing hidden. They should be luminous and be seen in an otherwise dark environment. I found that by focusing on these very particular goals, far from being a restriction, it was a liberation as it opened up ways of working I might never have considered.
The Wave Equations
Early on in my research, I made an important discovery that was to be the foundation for many later works. I discovered an interest in waves and vibrations and a particular way that they could be visualized. Waves come in many forms but what perhaps makes them so intriguing is that the many forms share so many properties. When you sense a wave, it contains something universal that it shares with other waves. I started my research in the 80s when new dynamical theories came to prominence known generally under the title Chaos. Now Chaos theory has numerous fields and areas of application. The most famous is perhaps the Mandelbrot Set. This is a beautifully complex mathematical form, but it does not teach us everything we need to know as it is static and Chaos is chiefly a theory about change. Perhaps the Butterfly Effect is the most well known idea that well embodies the idea of Chaos. It says the smallest and most unknowable of inputs can lead to the largest most drastic consequences. In the main the most interesting discoveries of Chaos Theory are to do with the emergence of new forms of pattern and order and are not really chaotic. Lynn Margulis is most famous in this field with her contributions to understanding the origin of life.
What I discovered was a realm of waveforms that could be modulated between the more familiar harmonic forms and these new chaotic forms. I have given them different names at different times but in the first place these waves I explored were waves on a string and so it was natural to think about their connection to string theory. My waves are literally made with string. My original goal had been to build a miniature form of skipping rope powered by two model motors at each end. To my delight when I first switched on my gadget, it exhibited not one simple harmonic form but a host of varied forms. These forms are fascinating to look at and can be enhanced by a variety of methods of lighting them.[Figure 2]
In part these forms can be understood using the conventional theory of harmonics but it is their chaotic properties that give them their most distinctive character. In the first place I built small desktop sized sculptures that exhibited these beautiful forms. These were illuminated with chromastrobic light, light that changes colour faster than the eye can see. The colours are still visible when illuminating rapidly moving objects, different parts of the vibrating form will be lit in different colours depending on their phase relationship. Gradually I experimented with building larger and larger pieces until they grew to monumental size as much as 12 metres high.[Figure 3]
Today I continue to work with waves and am currently involved with a program to develop more sophisticated chromastrobic light. The lights I am using now are the latest high power LEDs, arranged in groups of red, green and blue; they can produce any colour by varying their relative intensity. I am working toward having complete control of the exact colour at a very high frequency that is synchronized with the wave forms. In this way I can bring out distinctive subsections of the wave related to a particular phase in a different colour. Currently we can divide the phase of the waves into eight regions of variable length and assign an individual colour to each of these, varying the colours freely over time. I have been assisted in this work by Louis Norwood, a young and enthusiastic electronics engineer.
Comparing string theory with the strings in my work, the most radical difference is not the scale or the dimensionality, huge those differences are, it is that string theory deals with vibrations that are very pure harmonics. The physicists’ strings behave like the strings of a musical instrument and do not undergo vibrations with large amplitudes and complex movements. I am sure physicists are for the most part are unaware of my discoveries and it would not sit comfortably within their framework. For string theorists, exploring the higher dimensionality is the primary challenge, the waves in string theory are straight forward. Although a number of mathematically minded people have given consideration to a theoretical analysis of the behaviour of the strings in my sculpture, no one has produced a convincing description.[Figure 4]
Discovering the chaotic behaviour of string waves was pure serendipity. More recently I have consciously chosen to include a scientific theme in my work. The most complete and perfected installation I have created to date, Timeless Universe, was inspired by the work of Julian Barbour. His book, The End of Time, became the starting point. Inspired by his work but seeking to contextualize it within the wider human search for a cosmology, I chose texts from many other cultures along with signs, mathematical symbols and equations, combining them into a flow of images that were projected onto a collection kinetic light sculptures.
The installation was created at the Sala Parpallo, a gallery in Valencia. I am much indebted to the staff and in particular my curator Angela Molina for making this possible. The gallery is housed in a five hundred years old building and was, as it turned out, particularly well suited. Originally a nunnery, part of the building was sold to the city council some years ago. The main exhibition space was originally the refectory. It is a tunnel shaped room with an arched ceiling around thirty five metres long and six metres tall and wide. At my suggestion they agreed to seal all the windows and repaint the room entirely black and provide a fitted black carpet. It took on a cave like quality of extreme darkness. The space was divided into three sections. Visitors entered from one end and found themselves drawn deeper and deeper in. The first area showed a collection of wave based sculptures, the second a collection of other spinning kinetics, but it was the last area that occupied almost half the total space where I created a new collection of works that together formed the Timeless Universe installation. They were lit with video projectors but because visitors were not viewing screens but a collection of kinetics, many did not realise how they were lit at all. The impression was of luminous glowing forms suspended in a dark space. Each form possessed a high speed component whirring at a velocity that blurred the details of construction. The material out of which they are made appears to be light, it is transparent and does not look like ordinary solid matter at all. Onto these transparent forms are projected slowly changing images.[Figure 5]
The images are generated in real time with code I have written. Early on in my career I dabbled with code writing. I remember the first rush of this most clearly from my days as an art student. Our college at that time did not possess a single computer, but I jumped at a chance to go up to London on a special short course to learn about computer art. In the space of a few days I grasped the elements of a simple language that’s allowed its user to generate designs printed on tractor feed paper using only the standard ASCI symbols. Unlike a standard console, the specialised language allowed the user to define rules for what characters shall be printed at a particular location on the page where the locations are treated as members of a matrix. I rapidly started to write codes that embodied the principle of growth and expressed it as communities of ‘O’ and ‘X’ and other simple signs. I returned to my regular college carrying a sheaf of tractor feed as thick as a phone directory.
This was to be an isolated taste. I must have been on that course in the mid 70s, just a short while before the advent of personal computers, and when PCs did appear, I was not an early adopter as I judged that what was possible on those models still lacked the visual richness that could be achieved by analogue means. It was not until the 90s that I returned to computing and finally found again my love of writing code. This time, with a colour monitor instead of a tractor feed printer my excitement really took off. I learnt the programming language Delphi. I have tried other languages, but I find this language is very well suited to my needs. It is powerful, creating fast executable code far superior to anything I could achieve with Java or Visual Basic and easier to learn than C++. Over the years I have learnt how to write commands to OpenGL and developed a virtual world of my own that I can populate with virtual kinetic sculptures that subsequently I can project onto my actual kinetics. This has allowed me to bring together my interests in kinetics, a media based on moving parts, with computing in my own distinctive hybrid.
For Timeless Universe, the crucial extra ingredient I knew would be the choice of a suitable collection of « textures ». To a 3D programmer a texture is an image that is used to paint onto a 3D form. The process of painting can be intentionally faithful to the original to image. Construct a box and paint it with suitable photos of a house viewed from each side and it takes on a life like quality. Alternatively we can play tricks with the texture. It can be programmatically distorted so as to make it more or less unrecognizable. At some point around five years ago I created a program I called Cubism, as it possessed a comparable visual feel to the movement in painting and used techniques with modifying textures to explore the boundaries between recognizable and unrecognizable. This I decided would be perfect for Timeless Universe as it well captures our sense of intellectual struggle to comprehend ideas in a visual way. I selected images, many of them from rather dry mathematical sources and transposed them to be part of this kinetic world.[Figure 6][Figure 7]
The large installation, Abstract Cosmology, I created for the Reina Sofia in 2008 was entirely new but again explored a realm between recognizable and unrecognizable. I chose as my subject matter a stream of images that relates closely to the earlier piece and continues to explore my interest in non standard causality. I shall have more to say about this at the end of the essay.
The Problem in Physics
I will begin by trying to describe why I think it is so hard to combine relativity and quantum mechanics. Physicists describe relativity, both special and general, as classical theories. All science that precedes quantum theory is considered to be classical. The big break in thinking that comes with the quantum is largely associated with the introduction of uncertainty but while that is one way to understand the difference between these two realms, there is another perhaps much more important difference. Classical science attempts to build a complete description of reality. In principle a sufficiently thorough knowledge of the world combined with the right theories should allow us to know everything. What is missing from our observations can be inferred from theory. Of course quantum mechanical uncertainty we know now makes this impossible but there is something else different about the classical way of thinking. In classical physics we understand that the scientific concepts actually exist: for example a gravitational or magnetic field is really present and we can measure it. While Einstein replaced the gravitational field with the concept of curvature of spacetime, this curvature is every bit as real and measurable. In quantum mechanics and all later ideas, there is no claim that the ideas under discussion necessarily exist at all. Ideas can become abstract. A quantum state is a purely mathematical entity, it has no physical substance and could not have, as far as we can tell, and yet the state becomes a powerful way to make predictions.
The transformation from a realistic way of thinking to an abstract one is central to how physics changed during the 20th century. While some of the most profound discoveries, for example atoms and their nuclei definitely exist, things become less clear when discussing individual particles or quanta. They exist when we observe them but what is happening between observations remains unknown. By moving to an abstract approach it liberated physicists to think in ways that would have been impossible before: suddenly mathematics was no longer slaved to being a literal description of the world. Any idea, however strange was possible. Relativity when considered in this light seems quite ordinary and old fashioned, and yet at the time Einstein first conceived it, not only was it revolutionary but carried with it deep enigmas that were to trouble Einstein. Much of this tends to be overlooked in the description of the subject because it all seems such a minor point compared with the difficulties that came later.
Einstein worried about spacetime. To see why, consider this. He had shown that how we determine time is dependent on our frame of reference. For observers moving in different frames, not only are their clocks changing at different rates, but their judgement of when events occur simultaneously changes. In a Newtonian world there is only one shared moment that is now, the only time that actually exists. But Einstein found that this is not the case at all. Einstein realised that his theory is saying that this thing we call « now » depends entirely on how you are moving relative to the world around you. And since different observers are each moving in their own frame of reference, then all these « nows » must co-exist. The only consistent way to understand spacetime is to say that it all exists, the past, the present and the future, everything. This troubled him but it is the correct way to think of relativity. It is an entirely static theory of existence where everything resides in a block of spacetime and if we are to accept its literal truth, then not only does the past continue to exist but the future fully exists and is pre – determined. Uncertainty must be an illusion, and its appearance in quantum mechanics the consequence of some still to be discovered limitations in our knowledge. As a piece of classical thinking this cannot be faulted. We must take literally the existence of the physical ideas. But today physicists do not consider spacetime to be a real physical thing. It, like all other ideas in physics, is seen to be a mathematical idea. Einstein lost the battle but did he lose the war? It turns out to be extremely difficult to entirely expunge this classical way of thinking. To bring about a final peace treaty, and find unification, we need to resolve the underlying conflict in ways of thinking.
Time is one of those deep problems, and if it could be understood better, it might make it easier to achieve unification. I now return to Barbour’s suggestion that it does not exist. Barbour’s proposal accepts the co-existence notion that Einstein was forced to confront but casts it into a new entity: a configuration space. In trying to understand what that is, I begin as Barbour does with considering the triangle. Imagine a collection of triangles. We are only interested in their geometric properties but we could imagine them as actual physical objects, say like parts of a jig saw collected in a bag. This bag full of triangles is a physical representation of a « configuration space ».
More abstractly we can now imagine using Cartesian coordinates, x, y and z to represent the lengths of the sides of the triangles. Pick a point in space and its coordinates then tell us the particular triangle this point represents. So our easy to imagine 3 dimensional space can be used as a way of representing all possible triangles. A triangle close to the origin is small. A triangle far from the origin but close to one axis has one small side. An equilateral triangle must lie along a line equidistant from all three axes and satisfy the equations: x = y = z.
Now if we want to construct a configuration space to represent all possible quadrilaterals, we would have to add an extra dimension. One extra dimension will be enough if they are all shapes that can be cut from a flat material but if we further allowed them to be four points in 3D space, then the situation gets more complex again. I will not continue but you will gather that Barbour’s idea requires more and more dimensions. The configuration space becomes impossible to visualise but continues to be simple to express mathematically. The shape however complex in each case is represented as a single point in that configuration space. A configuration space for the shape of the universe then becomes a hypothetical entity that has extra dimensions to indicate the positions of every particle in the entire universe. It has to have at least 3 times as many dimensions as particles in the universe at a minimum. More if we want to assign properties to the particles. While it might seem like a horrific extra complication to replace our familiar idea of reality with this infinitely dimensional entity, to Barbour it offers elegant simplicity because now the entire universe is a single point in this greater whole. To be more accurate I should say the entire universe at any particular moment.
Configuration space can be imagined then as home to a collection of points, all of which are different moments, or « nows », as Barbour prefers call them. The space is huge: large enough to accommodate all the variety of possible configurations as implied by quantum mechanics. We are no longer limited to a single future. Barbour has done a great deal of work on showing that his concept is consistent in principle with physics as we know it, both general relativity and quantum mechanics but what else does it tell us? I asked him whether time travel was possible or precognition. He was dismissive of such ideas and insisted that although his idea encompassed the idea of all possible states of space and time coexisting, it did not imply any extra interconnectedness between those states. This I found unsatisfying.
One of the other great unsolved enigmas is the problem of non locality. Two quanta, once entangled, remain interconnected even when they are moved arbitrarily far apart in space and time. Non locality I have always suspected implies that neither space nor time is fundamental. Distance is as much of an illusion as time. Barbour’s proposal does not address this problem, nor does it allow for any of the more exotic ‘science fictional’ possibilities I asked about. In short despite being mathematically and philosophically strange, it describes a world that still behaves in a normal, perhaps one might say semi classical way.
To other physicists this is potentially a plus. Although they work in the realms of abstract and strange mathematical ideas, for those idea to be useful they have to make predictions that are consistent with the world as we know it in the main. Physics advances almost entirely through very subtle changes in our expectations. Mostly a new theory will predict exactly the same as an old theory but in some very specific circumstance it should make a different prediction and that then becomes the crucial test, as for example when Einstein predicted that the sun would bend light and Eddington confirmed this prediction during a solar eclipse in 1919.
For a physicist today to invent a new idea, the first thing he must do is develop it to the point that he can subject it to some kind of test. Observational tests that would provide proof are the hardest to find and in the age of String Theory have become distant goals. Instead the physicist must look for more abstract and general ideas as a guide. Is his idea self consistent? Is it consistent with the known laws of physics most of the time? This process of critical assessment means that every creative mathematical idea is subsequently subject to a very harsh process of evaluation. There are far more mathematical possibilities that are more or less certainly wrong than any that are likely to succeed. The situation has become far worse than the proverbial needle in a haystack. The price to pay for going into the realm of abstract thinking is that it has thrown up such a wealth of hypothetical universes.
One of the critical processes that could be applied to test a new theory is to consider how causality operates. It has long been known that physics as it stands now does not contain a clear arrow of time at the fundamental level. This is something of a mystery as although it cannot be deduced from currently known first principles the community of physicists are mostly in agreement that any form of time travel must be impossible. For that reason any new idea that would imply this possibility is likely to be given short order and consigned to the bin. Perhaps physicists are being over hasty in dismissing a class of possible theories as a result of the expectation that this is good test of its probity.
In 2006, John G Cramer, of Washington State University announced that time travel of information might be possible and entirely consistent with standard quantum mechanics. His announcement was met by a chorus of scepticism by other physicists and he failed to receive any official funding to test his idea. He did receive some funds from private donors but did not succeed in his initial attempts with the limited resources he had available to him and the idea rapidly fizzled out, failing even to achieve the notoriety of great failures such as cold fusion. I discussed the idea with a number of physicists and in most detail with Renaud Parentani of the University Paris-Sud. There seems little doubt that Cramer’s specific proposal was almost certainly wrong but the underlying idea was not without merit. It arises from the symmetrical nature of time as expressed in quantum mechanics. The Schrödinger equation evolves over time but with no clear indicator of what direction should be labelled forwards and backwards in time. Schrodinger’s equation specifically contains both a ‘t’ and a ‘-t’ component and Cramer had in 1986 proposed an interpretation of quantum mechanics where information was exchanged in both directions through time but his initial idea did not contain a way to observe this process. While many physicists see no reason to expect causality to ever operate backwards, there is no 100% clear proof of why it should not. Yakir Aharanov of Tel Aviv University and the University of South Carolina is another who continues to explore the time symmetric nature of quantum mechanics.
Sir Roger Penrose of Oxford University has argued that the human mind cannot be explained using the known laws of physics. His conjecture is detailed and technical and rests upon an extension of the ideas developed by Alan Turing with his Universal Turing Machine. He discusses problems that are non computable, specifically certain hard problems in mathematics but by implication I would argue that no computer, however powerful, will be capable of imagination and creativity, since these are also non computable. They are very distinctly human special qualities. The brain maybe thought of as a thinking machine but it cannot be understood by comparison with a computer. Penrose expresses the view that quantum mechanics must be wrong but gives no indication of how changes to physical law could lead to a deeper understanding of mind.
My experience tells me that precognition is real. I wonder: could creative people have some mental pathway giving them flashes of insight through contact with the future? I suspect I am not alone in having this feeling. Perhaps creative people have a greater sensitivity to what does not yet exist? An ability to anticipate that does not work in a rational way? The human mind, even the mind of a mathematician, is not always entirely reasonable. My own speculation leads me to wonder whether precognition could be the missing ingredient that allows us too understand mind. I propose we need to change our understanding of causality. Cramer I believe is right but his scope of focus does not take in this human aspect. Bringing together Cramer’s speculation with Penrose’s conjecture, I propose a deeper understanding of the human mind can emerge from changes in physics specifically relating to the structure of causality. Those same changes would have profound implications for the unification program. There is at least a remote possibility that one single breakthrough might lead to major developments in understanding in these two apparently unconnected fields of study.
I shall briefly explore the implications of precognition and a hypothetical time machine for information. I shall show that, subject to certain constraints, their existence does not lead to logical contradiction. Let us make the assumption that as far as any one observer is concerned there is something that shall be called future. The future we can be less sure of than the past or present and I will represent the general situation in figure 1 where I conjecture some connection from the future to the present.[Figure 8]
I propose that we divide the future into two realms, deterministic and non deterministic as shown in Figure 2. As an example of deterministic, consider the paths of the planets. They are almost perfect examples of the power of classical physics to make precise predictions where quantum mechanical uncertainty plays no part at all. The delta function is used in quantum mechanics to represent a situation where there is no uncertainty. There is only one thing that can happen and that is expressed by saying out of all the hypothetical possible futures, only one fine line contains a non zero and indeed certain probability of happening. In the example I have sited it is the paths of the planets. If we imagine some hypothetical time machine for information, what would this be? Let us say we discover waves that precede an event. Then rather than doing calculations to predict the position of the planets, we could use a new form of telescope to look for the planets future locations. This is just one aspect of the future that is certain.[Figure 9]
Another is almost certainly earthquakes. We have every reason to expect that they can be fully described by classical physics. Currently they cannot be predicted but in principle it should be possible and one day this goal will be achieved through further conventional developments in geophysics. Alternatively using our hypothetical « future wave » detectors we might directly observe future earthquakes. This idea may sound bizarre and highly unlikely but the transmission of information backwards through when it relates to future events that are themselves certain cannot lead to any logical contradiction.
Now consider the converse situation represented by the right half of diagram, the non deterministic future. This would apply presumably not only to quantum mechanics but in all situations where humans could influence the future. If say I was to telephone myself in the future using these hypothetical « future waves », I would expect that my future is not predetermined. I can react to events in an unpredictable way and if we now try to represent « me » using our quantum mechanical way of thinking the prediction is the future consists of a state or mixtures of states in which I am doing many things. If these future waves exist at all, they would be coming back from all these different ‘me’s and the message would be a mixture producing at most some kind of interference pattern: a scrambled and undecipherable signal.
The hybrid nature of physics provides a filter or constraint, the hypothetical future waves can be transmitted by all processes but we could only detect intelligible signals where the future was deterministic.
In writing about my installation, Abstract Cosmology, I have suggested that this kind of retro-causal thinking would be appropriate for understanding the Big Bang. Cosmologists face a choice: the older dating back to the discovery of the Big Bang is that the universe appears from nothing. This presents deep problems both philosophically and mathematically to explain how all came into existence « ex nihil« . The more recent approach is to suggest that there is meaning in asking what happened before the Big Bang and a number of different speculative ideas are under serious consideration. The problem with all of them will be finding evidence. Currently moving into the lead is the multiverse, the idea of an eternal inflation spawning an infinite number of universes, each with their own distinctive and different physical law. While this idea is certainly very interesting, it is deeply problematic.
I propose that we might be able to construct a cosmology with one universe if we allow the future to influence the past. This sort of « boot strap thinking » would certainly be rejected using conventional measures to test the validity of a theory. I believe causality in certain circumstances operates from future to past. The future, the present and the past are tied together in a subtle interdependence. The effects of the future on the past are mostly elusive and hard to detect. But at the moment of creation, in the absence of any other influence and with nothing preceding it, retrocausality predominates. This remains for now an abstract idea. It needs careful study. I hope I will inspire mathematicians and physicists to reflect.
I am at the moment writing as the lone voice of a scientific artist. I propose a radical new initiative in the unification of general relativity with quantum theory. I wait to see what the future holds and if anything of my idea makes it into the mainstream of scientific thinking.
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Paul Friedlander, « Outside Time », [Plastik] : Être ici et là : La relativité générale et la physique quantique #01 [en ligne], mis en ligne le 8 janvier 2010, consulté le 31 janvier 2023. URL : https://plastik.univ-paris1.fr/outside-time/ ISSN ISSN 2101-0323