In Physics we trust

by Tarun Biswas

The outsider inside

Let me start by annoying anthropologists. I shall comment on human nature without ever reading a book on anthropology -- It seems that the social instinct of the human being makes it want to belong to a group. Now, as a group member an individual is expected to conform to a set of rules and in no way challenge them or even question their self-consistency. However, an outsider to a specific group can challenge its rules quite freely. So, we humans spend a major portion of our intellectual energy challenging the rules of each other's groups. Some examples of groups are those of -- Christians, capitalists, Indians, Moslems, Englishmen, communists, chemists, anthropologists, democrats and so on. The enthusiastic reader may wish to classify these groups according to their nature -- religious, national, academic and so on. Such a reader, by now, might also have guessed from my style of writing (or my affiliation) that I belong to the group of physicists.

I also belong to that subgroup of physicists that take their divine right as outsiders of religious groups very seriously. This is the above mentioned right to challenge the rules of all groups other than one's own. So a significant fraction of my intellectual energy has been spent in challenging religious thoughts and uncovering their inconsistencies. In fact, this role of the outsider has so fascinated me that I have gone beyond just the religious groups. I have challenged capitalists, communists, psychologists, anthropologists, democrats and many others. The fascination has eventually grown to the point where I have been driven to blasphemy by violating the primary rule -- Thou shalt not challenge thy own group. This annoys physicists to no end. I am like their trained pit bull that has turned on its master. To explain my own deviant behavior, I have even psychoanalyzed myself -- only to annoy psychoanalysts.

In the following I shall present a taste of that forbidden fruit that I have picked as the universal outsider and in particular as the "outsider inside" the world of physicists. At least for me, this fruit has led to confusion as it has brought to light strong similarities between physics and my original target of criticism -- religion.

Physics and religion -- similarities and differences

Human beings have always wanted to have some control over their own future. This translates to having control over their environment which is often referred to as nature. In controlling nature, one needs to achieve the following goals which we shall refer to as the GC (goals for control).

  1. Explain observed natural events.
  2. Predict natural events before they occur.
  3. Manipulate conditions to change the future course of natural events in desirable directions.

The beginnings of both science and religion are in the realization of the GC. But their methods are very different -- or at least that is what history would have us believe (now I have annoyed historians as well!). The present methodology used by my own kind of scientists, namely physicists, has remarkable resemblances to that of most religions. But let me first consider the popularly stated methods of religion and science. From here on, I shall restrict my comparisons to only one of the sciences -- namely physics. This is because, in physics, the GC are stated most precisely and are also most likely to be forgotten. Most of my examples will be from particle physics as it is my field of specialization and also because it challenges the basic principles of physics more than other fields of specialization.

In religion, the first item of the GC is taken very seriously. In fact, religion explains everything in nature. It postulates the existence of a God that created everything and makes everything happen the way it does. So there is one postulate that is enormously complex but the explanations are very simple. Such an approach scuttles the other two items of the GC because it does not provide any methods of prediction or control of nature.

The physics approach, on the other hand, attempts to explain very little. However, it provides better means of prediction and control. In fact, in physics, the term "explain" has a meaning critically different from that in religion. A physical explanation is not complete unless it provides some degree of predictive power and control. This requires physics to have several simple postulates which provide complex explanations. The simplicity of the postulates allows prediction and control. Although the number of postulates is large, constant attempts are made to reduce their number through unification. Interestingly, it is noticed that such attempts at unification of postulates, in general, make them more complex and reduce their predictive power. This can be seen to be a move closer to religion!

A serious weakness of physics is being slowly revealed in current days. It is in the tacit assumption that complex natural phenomena can be disentangled and looked upon as a "sum" of several simple phenomena. Physicists call this the assumption of linearity. Most physical phenomena studied in physics, until now, were linear. Such a bias was probably due to an inability to understand nonlinear phenomena. There ought to be no shame in admitting this weakness. Nonetheless, physicists, very often, deny it and attempt to explain inherently nonlinear phenomena using results of linear theories. The explanation of astronomical objects called binary stars is an example. Einstein's theory of general relativity and its experimental tests have conclusively shown gravity to be a nonlinear phenomenon. However, general relativity itself is not complete enough to explain binary star behavior. This has encouraged a bumper crop of dubious theories that claim to explain binary stars while they ignore most effects of nonlinearities. Such theories provide no new predictive power or control and hence their explanations are mostly religious in nature. This and other examples of religious explanations in physics will be discussed in greater detail later.

At this point, it is important to point out that a popularly accepted distinction between physics and religion does not truly exist. Unlike religion, physics is considered not to be based on faith. Evidence to the contrary is seen in the postulates of physics. The postulates themselves are not directly a matter of faith as they are tested experimentally. But there is significant faith involved in believing these postulates to be correct at all places and at all times. For example, the laws of gravity have been tested only for a handful of astronomical objects and some man-made objects. However, if one were to claim that an unpowered spaceship could be sent into a triangular orbit around the Sun, physicists would bet their lives against it. This is a matter of faith in the inherent predictability of nature.

Self-consistency of religion

One standard critisicm of religions is their lack of logical self-consistency. A popular example is in the principle of the omnipotence of God. It results in situations where a statement and its negation are both false. An example is the statement -- God can create a rock that He Himself cannot break. Such problems in religion occur due to a need to ascribe humanly desirable qualities (like omnipotence and omnipresence) to God. This forces a religion to have more than one postulate which leads to the problem of postulates contradicting each other.

A simple way of avoiding such contradictions is to make sure there is only one religious postulate --- There exists one God who does everything. This circumvents questions about God's abilities which might be contradictory. The explanatory power of such a postulate can sometimes be surprising. For example, I can press the switch in my office to turn on the lights. Then I may argue that it was my decision to turn on the lights and hence God couldn't have done it. In fact, if I had not pressed the switch the lights wouldn't have turned on. This I demonstrate by not pressing the switch. But the religious argument would be that it was God who made me press the switch and when I do not press the switch, it is once again God who forces me not to! Although all religions have the flavor of such a single postulate approach, none of them (to my knowledge) strictly adhere to it.

The heirarchy in the church of physics

If the similarities in the goals and methods of physics and religion are not surprising enough, one could look at the similarities in their structuring of authority.

Great physicists like Newton and Einstein have the status of saints because their ideas have withstood the test of time. Most physicists do not dare question the authority of such figureheads.

The high priests of physics, like those of religion, are usually not known that well by name. However, they wield enormous power over the followers. They decide what experiments and theories in physics are "important". They themselves are not seen very often. But they lead large subgroups of physicists that are sometimes lovingly called "bandwagons".

Lower level priests are in charge of transmitting the messages of high priests to the general following. This is usually done through invited papers at large religious gatherings called "conferences". Priests of this level also control and censor the thoughts of the masses by refereeing articles in journals.

Members of the masses that aspire to becoming priests, must follow the thoughts of the high priests. So they attend as many conferences as they can. To prove allegiance, they present contributed papers at conferences and try to publish articles in refereed journals. If their thoughts are not appropriate, other physicists ignore their contributed papers and lower priests stop the publication of their articles. However, such drastic measures are usually not necessary. Most physicists realize the sinful nature of their thoughts when the referee's report says, "This is not of sufficient general interest". Sometimes more serious infractions might receive remarks like, "This is altogether wrong". A reason or proof of the error is seldom required.

Saint Newton

Although Newton has been found to be wrong in some respects, he is responsible for clearly defining the goals of physics. In his second law of motion lies the primary philosophy of physics -- prediction through differential equations. The assumption is that if the "state" of a natural system of objects is known completely at one instant of time it can be predicted for all other times. In Newton's second law the "state" of the system refers to all positions and momenta (related to velocities) of all point objects in the system (larger objects can always be treated as collections of infinite point objects). It is true that the modern and more precise laws of physics come from quantum theories that point out that Newton's concept of the "state" of a system can never be precisely specified. However, the general idea of prediction of "states" at all times from the knowledge of the "state" at one instant of time is still present in quantum theories. The quantum "states" have a different and more complicated physical meaning.

Due to this Newtonian philosophy of prediction, physicists, for a long time, have been coming up with differential equations related to such prediction. As a result, such equations have become very important in mathematics. They are commonly referred to as the "initial value problems". Most physicists, consciously or subconsciously, are faithful to this philosophy of predictability. The philosophically oriented physicist will often justify this faith by the fact that nature seems to have always corroborated it. But the unfaithful might be quick to point out that physics experiments focus only on the predictable through the requirement of repeatability. Hence, it is no big surprise that they never report unpredictable events!

In spite of the doubts of the unfaithful, we physicists (including yours truly) worship Newton. However, sometimes our respect for him does render us blind. When Huygens proved light to have a wave nature, physicists ignored him. This was simply because Newton was thought to be against such a concept. It was immaterial that Huygens could actually prove his conviction. Besides, it is not even clear that Newton himself was that strongly against it. Physics students, to this day, do the "Newton's rings" experiment which is considered to be conclusive evidence for the wave nature of light! This illustrates another similarity of physics to religion --- The followers believe in the prophet's word more than the prophet himself does.

Newton's long shadow hindered Einstein as well. Einstein's theory of relativity is still considered to be very difficult. This is mostly because the early training of physicists solidifies the Newtonian concept of absolute time and Euclidean space. The original bias against the theory persisted so long (in spite of strong experimental evidence) that Einstein did not receive the Nobel prize for it.

Saint Einstein

Einstein is a latter day saint. After the initial opposition from Newton worshippers, he has now been accepted as a saint himself. From a philosophical point of view Einstein's work was not as significant as Newton's. Nonetheless, it was a tremendous conceptual leap. Relativity taught physicists a lesson in humility at a time when they had started claiming complete knowledge of nature as a whole. It was probably this shattering of ego that partly prevented the prompt acceptance of the theory.

Now that Einstein is a saint, physicists have stopped questioning him altogether. The general theory of relativity is still incomplete in many respects. First, it can predict the motion of only small test masses. The theory, not being linear, does not allow simple extrapolation from small test masses to large ones. Second, it cannot incorporate nongravitational forces. Third, its predictions depend strongly on the topology of space-time, and it cannot predict this topology. Fourth, it is not clear about what kind of mass is a source of gravity. The energy of the gravitational field has an equivalent mass which does not seem to be included as a source for the field. This is seen from the Schwarzchild solution which is an empty space solution but still has the gravitational field energy mass. However, from an experimental point of view, it is not clear how one could separate the masses that are sources of gravity from the mass of the gravitational field itself. This had, quite clearly, bothered Einstein as he had considered the loosely defined "ponderable mass" to be the source of gravity. Present day relativists spend very little time worrying about this problem.

Finally, physicists seem to have forgotten that the experimental tests of general relativity test only a very weak gravity form of it. As the very first tests, these were very good. However, the lack of any further experimental evidence in seventy years is mildly embarassing. At this stage, I am likely to be mobbed by physicists who will claim many such experiments have actually been done. However, on closer scrutiny, it is found that these later experiments provide very little by way of new tests of general relativity. For example, the pulsar timing experiments prove the existence of quadrupole radiation from binary stars. Even if this radiation is actually gravitational, it could be predicted by almost any theory of gravity that satisfies only the special theory of relativity. Very often the situation is further complicated by the introduction of the so called post-Newtonian approximations of general relativity. These approximations are definitely not approximations of general relativity. They introduce independent concepts to allow effects of nongravitational interactions. The resulting theories may not even be self-consistent.

Religious theories

Next I shall show that for a long time physics has not been as close to religion as it is today. Earlier, I had distinguished religious explanations from scientific ones. A scientific explanation is supposed to provide some predictive power and control. These extra aspects of a scientific explanation are quickly dwindling from modern physical theories.

Einstein's general theory of relativity is a fascinatingly powerful theory of gravity. It provides both predictive power and control (even though these means of control are mostly outside of human reach). However, like most theories, it has limitations. One such limitation is its inability to predict the motion of extended objects with large internal nongravitational forces. All attempts at extending the theory in a self-consistent manner to include such systems have failed. In such a situation, it is appropriate to try solving the problem in small increments. The result is a set of theories that are called the post-Newtonian approximations (PNA). It is to be noted that these theories are not merely approximations of general relativity. There exists no approximation procedure that will lead to a PNA from general relativity. This, of course, is expected as the PNA's indirectly deal with nongravitational forces and general relativity cannot. The next step should be to test if such theories can explain anything that trivial extensions of Newtonian gravity cannot. So far, there exist no such tests. To make things worse, it is not even clear if these theories are self-consistent. In such a situation one would expect proponents of these theories to either abandon them or fix their problems. On the contrary, such theories are vehemently promoted as conclusive.

Since the beginning of this century, the process of fixing theoretical inconsistencies has led physicists from classical mechanics to quantum mechanics and finally to quantum field theory. The first quantum field theory was quantum electrodynamics (QED) and it described the interaction of electrons and photons. It enjoyed dramatic experimental success. These were the days of glory for physicists. Armed with the success of QED, physicists decided to explain strong interactions (for example the interaction between protons and neutrons) with a similar theory. It did not work. Then it was experimentally found that strongly interacting particles like protons and neutrons have a substructure. The constituents were called quarks. A new theory of quarks, patterned after QED, was then proposed. This was called quantum chromodynamics (QCD). Mathematically, this theory is beautiful but conceptually a nightmare. The success of QED was based on the mathematical method called perturbation expansion, the working of which depends critically on the vanishing of the interaction when the particles are taken far apart. For quarks, the interaction is experimentally known to grow without bound when they are taken apart. Despite this, it might have been fruitful to work on this theory for a while. It has now been almost three decades since this theory was proposed. Nothing experimental has yet been predicted by this theory that couldn't also be explained by relatively trivial theories. However, the belief in the theory has gotten progressively stronger. At the present time any article that contradicts this theory or proposes an alternate one gets rejected by journal referees. Then it is claimed that QCD is the only viable theory of strong interactions and that it has been experimentally verified beyond doubt. This makes QCD a masterpiece among religious theories.

The evangelists

In most religions there are periodic appearances of prophets who extricate followers from philosophical confusions. After every such appearance, there is a period of clearer thinking among the followers. But with the passage of time confusion reappears and another prophet becomes necessary. This pattern is seen in physics as well. Some of our prophets are Newton, Boltzmann, Maxwell, Planck, Einstein and many others. At present we are overdue for a prophet.

In religion, the sign for a prophet being overdue is the appearance of evangelists that try to cash in on the existing confusion. This sign is showing very clearly in the present day physics community. Influential physicists are surrounding themselves with followers and calling themselves research groups. The topics of "research" of such groups have little to do with the investigation of the unknown. The purpose is to rake in public funding. In fact, the instruction books for applicants of public funding (e.g. those of the National Science Foundation (NSF)) require that an applicant have a concrete idea of what he/she expects the results of his/her "research" to be. In the days of clearer thinking one might have wondered why any research is needed when the results are so well-known! But today we do not ask such questions and the evangelists continue their fund gathering for trivial projects. The results of such projects are often suitably "dressed up" to look like great successes. Why do NSF and other public funding organizations allow such highway robbery? They believe physicists to be so smart that no one other than themselves can judge the quality of their work. As a result, in this game of gathering public funding, mutual back-scratching clubs are formed. Besides, public money is nobody's money and hence, nobody need care if it is wasted.

Some years back the ultimate evangelists had appeared. They wanted to build this mammoth particle accelerator called the Superconducting Super Collider (SSC) using public money. Note the repeated use of the term "super". This art of using terms like "super" or "ultra" has been borrowed from the advertizers of more useful products like detergents. The people convinced of the usefulness of this project were mostly the ones who were likely to receive a paycheck from it. As a result, these evangelists were campaigning to convince everyone that some fraction of that ten billion dollar SSC budget was likely to come their way. Different parts of the monster were to be built in different states, so state political representatives would vote for it. Physicists of every denomination were being promised jobs on this project to get their support. But would this project do anything for physics? Would it do anything more than create temporary and unproductive jobs? I am still waiting for our next prophet to forcefully ask such questions. He/she will, most likely, be crucified for it. Luckily, at least for now, confused political maneuvering accompanied by legitimate public outrage has terminated this project.

In search of a prophet

Given my scientific background, I refuse to believe that a prophet has divine origin. It is more "natural" to believe that an ordinary mortal is forced into prophethood by existing conditions. At present the conditions seem just right in the world of physics for the appearance of our next prophet. Some of the more relevant conditions are as follows.

Hence, I shall conclude with a hopeful note. The appearance of the next physics prophet (or prophets) is imminent. Let us be ready for it.

Looking for references?

As the reader may have noticed, no references are quoted in this article. This is not to say that my ideas are unique and cover uncharted territory. But quoting references would defeat a fundamental purpose of the article. Here I am trying to stress that the search for truth should not be hampered by any authoritarian influence. Hence, the authenticity of my statements cannot be proved or disproved by merely quoting authorities.