Chapter 5

CLASSICAL AND MODERN PHYSICS

It is now necessary to review the impact of quantum theory and relativity theory in order to see if they have any relevance to the "Body Mind" problem. 

First - Quantum theory. In modern physics we have two sets of explanations about the position of a particle, one in terms of classical physics, which is well understood, and the other in terms of quantum theory which is well understood in mathematical terms but which has some features which appear to defy common sense. We will probably have to wait for developments in this area before a complete explanation can be given. We will now consider the time and locality problem faced by modern physics.

THE TIME AND LOCALITY PROBLEM - Classical physics & quantum theory
(Physists familiar with EPR could skip the first part)

At the time when Isaac Newton was laying the foundation of classical physics with his theories of mechanics and gravity and when he split a beam of light into a spectrum using a prism, there was considerable controversy as to whether light was a wave phenomenon or whether it was a stream of particles. Newton believed very strongly that it was a stream of particles. The matter seemed to be finally settled in 1802 when Thomas Young carried out his famous double slit experiment. He illuminated a pair of slits, very close together, with a point source of light. The resulting image was a series of alternating light and dark bands. The conclusion was that this proved light to be wave phenomenon. The waves from one slit interfered with those from the other, resulting in a pattern where the waves alternately canceled or reinforced one another as they went in and out of phase.

In 1873 James Clerk Maxwell published his Treatise on Electricity and Magnetism, uniting the two and explained the nature of light as an electromagnetic wave phenomenon, combining magnetism and electricity. He even went so far as to predict the possibility of creating long wavelength electromagnetic waves using magnets and electric currents in the laboratory. Heinrich Hertz succeeded in doing this in 1888 when he generated Hertzian waves (Radio). At that time it appeared that classical physics was a deterministic system of cause and effect which could in principle explain all natural phenomena. Helmholtz was very emphatic against there being any "Life Force" or "Vitalism" which was outside this system and he held the view that in principle everything was explainable in terms of physical laws if you could only find them. Following the synthesis of urea, by Wohler in 1828 it was not long before a considerable body of organic chemistry became known and therefore it was not unreasonable to expect that life processes could be understood.

The system of classical physics began to unravel in 1887 when Michelson and Morley carried out their famous experiment, though no one realized it at the time. Up to then everyone agreed that light was an undulatory phenomenon and if you had waves you had to have a "Medium" to carry them along. That medium was called the "Ether". Helmholtz was able to explain all of the known properties of light very nicely in mathematical terms on the basis that light consisted of vibrations in the ether. The question then arose as to whether the earth was stationary with respect to the ether. Was it moving one way through the ether at one time and then in the opposite direction six months later? Perhaps the earth as it moved along, carried a considerable body of the ether along with it. Michelson and Morley sought to answer this question by comparing the velocity of light along the direction of the earth's motion with that at a right angle to it. The apparatus was as shown in Figure # 15.

Nowadays the experiment would be performed using a laser as the source of light. A beam of light is split into two by a half silvered mirror. one beam goes straight through in the direction of the earth's motion and the other is sent at right angles to it. The beams are recombined later by the mirrors and the image produced by the two interfering beams is recorded on a photographic plate. As in the Thomas Young experiment you get an interference pattern of alternate light and dark bands. Michelson and Morley mounted their apparatus on a rigid platform which they floated on a bath of mercury. They were then able to rotate the whole apparatus through a right angle without any vibration or distortion. The beam going at right angles to the earth's direction should be unaffected by the earth's travel. The other one, which traveled in line with the earth, ought to be affected thereby. You do need a bit of algebra to demonstrate this but it is quite simple. The analogy is a boat going upstream in a river against the current and then downstream again, this time with the current. Does it take a longer total time for the round trip than it would without a current? Actually it does. With the experiment you ought to get a shift in the interference fringes as you rotate the apparatus, if there is any change in the velocity of light. In actual fact there is no shift whatever in the interference pattern. This is a very sensitive set up for comparing the two velocities because the accuracy goes right down to the time light takes to cover the distance of just half of a wavelength.

At first sight you might think nothing of it. The experiment showed that the speed of light in a vacuum (which they did have) is constant, irrespective of the state of motion of the observer. On second thoughts it is distinctly weird. Imagine that you have an apparatus which will measure the speed of light from a beacon on the earth and you measure this. Then you step into a space ship and whiz away from the earth at a speed just a touch less than the speed of light and measure it again. You would think that the beam from the beacon would have some difficulty in catching you up if you are going so fast, and that it would take considerably longer to reach you than if you were stationary. You would be amazed to find that you measure exactly the same light speed. All sorts of explanations were thought up to explain this, including the idea that you shrunk a bit when you moved very fast as the ether material moved through you. In that case your theoretical "Measuring Rod" shrunk just enough for you to read the same speed. The problem was not solved until 1905 when Albert Einstein published the "Special Theory of Relativity". In this theory he confirmed that the velocity of light was a universal constant but certain other things which were always thought of as invariant were in fact not so, such as the rate of flow of time, mass, and the measurement of distance. The theory of relativity is basically philosophical and no more than simple high school algebra is required to understand its essentials. However it does bring into question some very fundamental concepts.

The next difficulty with classical physics was the problem of black body radiation. It was found to be impossible to explain the amount of heat emitted by a red hot or white hot body at various temperatures and the spectrum produced, on the basis of what was then known. In 1900 Max Planck discovered that he could solve this problem if, instead of heat energy from a red hot object being dispersed as light in a continuous fashion, it was being emitted in small packets of a definite size (Energy) which was related to the wavelength of the light. A similar problem occurred with the photoelectric effect. When ultraviolet light falls on a metallic plate, the plate develops an electric charge. This is due to electrons being ejected from the metal, carrying off both the electric charge and the energy of the radiation. According to the wave theory of light, one would think that the more intense the radiation, the more the energy of the electrons would be. This turns out not to be the case. The energy does not change. What you get is a larger number of electrons at the same energy. What does determine the maximum energy of the electrons is the wavelength of the light. Einstein was able to explain the reason. This was that the energy of light comes in distinct packets of a uniform size (Energy) and that energy depended on the wavelength of the light. This all fitted in with what Max Planck had discovered and the Quantum theory became established. Isaac Newton was right after all. Light is emitted as distinct particles but Helmholtz who believed in the wave theory of light was also right. Light sometimes behaves as particles and sometimes as waves. It has a dual nature. It turns out that electrons have a dual nature also. Sometimes they behave like particles as everyone believed. At other times they behave like waves. They can be diffracted, showing "Optical" interference, which indicates that they also have an undulatory nature. De Broglie produced a theory which postulated that any particle, if it is small enough, has an undulatory nature and a wavelength. In the case of a large object, which is composed of very many small particles, these wavelike effects cancel each other out producing an average so that the object behaves in the way that classical dynamics describes. (Actually large objects do have a wavelength but it is very short.)

Then we have the Heisenberg Uncertainty Principle. Heisenberg showed that it was impossible to determine both the exact position and at the same time the kinetic energy of a small particle such as an electron. Any observation would disturb it. He went further than that. He actually postulated that it never did have a definite position. The argument was that an entity is only real if it is, in principle observable. Einstein persistently clung to the contrary and deterministic view, maintaining that there must be an underlying reality which some physical theory can describe. He invented many thought experiments to try to demonstrate this and argued about them constantly with Neils Bohr, the Danish physicist. Bohr was always able to refute his arguments.

At about this time Max Born and Schrodinger invented the theory of wave mechanics and Dirac elaborated this into a fully developed "Quantum Theory" which can describe the behavior of waves and particles with remarkable accuracy down to a small part of a billionth. This was developed further by Richard Feynman into Quantum Electrodynamics (QED). This is where we stand today. Classical physics describes the behavior of larger bodies very well. Quantum theory also gives the right answers both for the large and for the small, covering the large as a special case. Large scale effects are simply the sum of what is happening to a host of tiny particles. At present we have to accept the weirdness and the philosophical difficulties.

When you look more closely at what is happening in the Michelson and Morley experiment or any experiment involving diffraction you find that a very weird non-locality problem arises when we try to define the position of a particle or a photon in such a set up. See figure #15 (The Michelson and Morley Experiment). Here a beam of light is separated into two parts by using a half silvered mirror. Later on, using mirrors, we bring the two beams together again and we get an interference pattern of alternate stripes of light and dark. The older and conventional explanation of this is that light is a form of waves and these are positive and negative values of electric field traveling through space. The positive and negative fields cancel out in certain places (Between the stripes). The trouble with this is that light sometimes looks like stream of particles. When the light intensity in the experiment is made very low, light arrives very slowly in definite packets (Quanta) all of the same size (Same energy) so that photons arrive only about once a second. (They can be counted by a photon detector which essentially detects discrete particles.) Although we appear to have particles arriving, we still get an interference pattern if we substitute a photographic plate. This means that each photon has to interfere with itself. The time between the arrival of seperate particles is too long for this to be a multiple particle effect. In other words the indivisible photon goes down both routes at the same time and interferes with itself. It seems to be both a particle and a wave at the same time. This defies common sense.

Wave mechanics solves this problem mathematically by saying that an elementary particle such as an electron or a photon has a dual nature, sometimes like a wave and sometimes like a particle. During flight it has a "Wave Function" which describes the probability of it being in various different places at various times, but it isn't actually in any particular place at any particular time. Then we are able to have the wave part of the wave function interfering with itself to tell you the probability of it being in some particular place. Some places turn out to be forbidden and the photon obeys the rules.

According to Heisenberg's Uncertainty Principle a particle or a photon does not have a definite position and velocity at any particular time except when it is actually being observed, i.e. when it is absorbed. When this happens, the theory states that the wave function collapses and at that moment we do have a more defined situation. We then have a well defined energy packet but its position is still indeterminate.

One of the problems with all of this is that you can arrange the Michelson and Morley experiment so that the two parts of the wave function are several yards apart, yet they have to be correlated. Greater distances may be involved. The "Fading" of short wave radio is also an interference phenomenon. When we are considering the phenomenon of "Fading" in a short wave broadcast between London and New York, the tiny photon of radio energy has a wave function which covers three thousand miles. It appears that what is happening to one part of the wave function (i.e, whether it is blocked,) instantly affects another part which is a thousand miles away. This boggles the mind. How can something which is so tiny be so big? It seems that the individual quantum is some kind of unity which can cover thousands of miles and which is not limited by light speed. One view of the theory is that every part of the wave function is in instant communication with every other part, so that it can collapse immediately if an obstruction is encountered. This could be taken to imply transmission in excess of the speed of light which would appear to contradict the general theory of relativity but this is a wrong view. We are dealing with the essential unity of the photon. It does turn out that this apparent communication cannot actually be used in practical communication. It is not to be regarded as an effect which travels at a speed exceeding that of light. This probably means that the theory of relativity is not violated.

To sum up, we find that we can describe all physical phenomena very accurately if we use classical physics for the large and quantum theory for the small, but there are many paradoxes which defy common sense and there is an acute locality problem. There has been much discussion amongst scientists about this problem and about what is called quantum superposition. This includes discussions between Einstein, Podolsky and Rosenberg about thought experiments which are referred to as EPR. There have also been some clever experiments by Wheeler and others which test some of these ideas. It turns out that whenever you devise an experiment which appears that it would defeat the quantum theory, the wave function collapses and the theory stands up.

The essential argument between Bohr and Einstein was about whether a phenomenon described by a physical theory corresponds to a definite reality, and whether you have definite locality (Einstein's View - "God does not play dice with the universe"). He stuck to his belief that an electron was a real thing which had to be in a definite place at all times. Bohr's view which denies this, is referred to as the "Copenhagen Interpretation". He believed in indeterminism and non-locality. Following thought experiments by Bell, some critical experiments were carried out by Aspect, at the University of Paris at Orsay in about 1983, which appear to settle the matter in favor of the Copenhagen interpretation. Recently further advances in electronics have made it possible to interrupt photons in flight using light switches which operate in nanoseconds. In theory one could test the EPR problem by using the Michelson and Morley set up by inserting a very fast light switch into one of the pathways after the point at which the "Decision" has been made regarding the route to be followed by the photon. In practice most of the tests have been made using pairs of "Entangled" particles. Similar EPR problems occur with these. For example - When a gamma ray gives up its energy to create an electron-positron pair, these fly off in opposite directions with equal energy but spins of opposite sign. However neither has a spin of a definite sign while in flight. Spin is randomly assigned, and statistics would apply. The two spins just have to be opposite. This is what is referred to as entanglement. Einstein's argument was that, on the face of it, you could, in theory find out about the state of one particle without disturbing it by measuring the other particle while it was a long way away. It could be too far away to communicate with its twin even at light speed. This might appear to violate the Heisenberg uncertainty principal (Regarding the spins as well as position and momentum). Bohr was able to answer this and the uncertainty principle still stands. Experiments by Nicolus Gisin at the University of Geneva appear to show that correlations between "Entangled" particles do hold over distances of seven miles or so. Correlations at this distance could not carried out by transmission at light speed. They appear to be instantaneous. The Einstein Bohr argument has been settled in favor of the Copenhagen Interpretation". It is probably wrong to imply any kind of communication between particles. A more likely interpretation is that the particle has an essential unity which extends throughout space, even at great distances. We have both indeterminacy and non-locality. It is clear that elementary particles like electrons and protons have very different properties from billiard balls and other lumps of matter with which we are familiar in every day life.

There are many books which explore these problems in depth including the following:-

The New Physics - Paul Davies
The Emperor's new Mind - Roger Penrose
Shadows of the Mind - Roger Penrose
Q is for Quantum - John Gribbin
The Matter Myth - John Gribbin
The Non-Local Universe - Robert Nadeau and Menas Kafatos
Where Does the Weirdness Go? - David Lindley
What Remains To Be Discovered - John Maddox
Taking The Quantum Leap - Fred Alan Wolf

It is quite possible that the mystery of the mind is bound up in some way with quantum theory as has been very forcefully argued by Roger Penrose ("The Emperor's New Mind" and "The Large, The Small And The Human Mind"). He places the quantum effect in some microtubules in nervous structures which are known to exist. It is difficult to see how quantum effects in microtubules could solve the integration problem, because the scale of activity is too small for the performance of the integrative function. He is probably correct to demand an explanation within the realm of physics and that could be within the area of quantum theory. There must be emergent properties of matter or energy which can manifest themselves in complex situations.

THE THEORY OF RELATIVITY
The theory of relativity is not considered to be very relevant to the problems addressed here. However, there is one aspect of relativity which could have a bearing on the locality problem of quantum theory. Einstein proposed that a four dimensional geometry truly represented the real world in which we live. The possibility that the locality problem, which we have with quantum theory could be solved by invoking an extra dimension exists. This only has a very indirect relevance to the integrative problem of the mind. You will find a description of the Theory of Relativity, along with my analysis of its relevance, in the Relativity Theory section of this web site.