Folse

The Early Years

Niels Bohr's theory of complementarity was developed over 70 years ago. He abandoned his model of the atom 1926, and yet it is still the way the atom is illustrated today in textbooks and on the internet. Complementarity never grew into other disciplines of science like biology as Bohr envisioned, and yet it is the underpinning of quantum theory and the way we view reality to this day.

In the introduction, Folse writes:

"Certainly of all the developments in twentieth century physics, none has given rise to more heated debates than the changes in our understanding of science precipitated by the 'quantum revolution'. In this revolution, Niels Bohr's dramatically non-classical theory of the atom proved to be the springboard from which the new atomic theory of the atom drew its momentum. Furthermore, Bohr's contribution was crucial not only because his interpretation of quantum mechanics became the most widely accepted view but also because in his role as educator and spokesman for atomic physics Bohr was very much the patron spirit of the entire quantum revolution. The conceptual framework which he proposed to provide a new viewpoint for understanding the quantum theoretical description of atomic systems became for most of this century the dominant outlook of countless productive experimental and theoretical physicists. He called this new framework complementarity". (Pg. 1)

Bohr invented the word 'complementarity' to convey the meaning of something containing many truths. Interestingly, Buckminster Fuller uses the word 'complement' to describe the outside of a system in his angular topography outlined in Synergetics. I am still not sure if they are talking about the same thing or not, though I suspect that either idea, if it doesn't already contain the other, can certainly be extended to.

Folse begins his book by examining the history of quantum physics. All the usual suspects are there and anyone familiar with quantum theory will feel at home immediately. Bohr's chief rival became Albert Einstein, and over a period of many years, the two engaged in a series of 'thought experiments' designed by Einstein to show the fallacy of Bohr's theory of complementarity.

" The immense influence of Bohr's complementarity viewpoint, as evidenced not the least in the historic debate with Einstein, naturally suggests asking why complementarity has been the subject of such frequent misinterpretations. Several distinct reasons probably contributed to the most important misunderstandings." (Pg. 24)

Many of Bohr's ideas are things we learned in grade school and are so much a part of our thinking that we never even question where those ideas came from. However, as the story goes on, we will see...

" First...Bohr often misused key terms in his arguments. He was not well trained in the vocabulary or the problems of traditional philosophy and thus did not always understand how his assertions would sound to readers who did not share his outlook. Furthermore, partially due to the uniqueness of his position, he often adopted a less than self-evident idiosyncratic expression to refer to a crucial point. Although from youth he was indeed keenly aware of what would normally be called 'philosophical problems', as we shall see in the next chapter, the formative influences which shaped his outlook cannot be said to have included any strong allegiance to a particular philosopher or school of thought." ( Pg. 24-25)

" Second, the nature of Bohr's writings did not lend itself to the presentation of his framework in any systematic detailed fashion. All of his philosophical work involves short essays, generally intended for public delivery to large audiences with diverse backgrounds. His three philosophical books are simply collections of these essays.

" Third, there were historical factors entirely out of Bohr's control that created a climate conducive to misunderstanding complementarity. Not the least of these was the fact that during the period of Bohr's philosophical work, most of those competent to write on the philosophy of physics were committed to some form of 'positivist' philosophy of science...a circumstance which was hardly conducive to the best understanding of complementarity." (Pg. 25)

" The dominance of positivism in philosophy of science also suggests a fourth source of misunderstandings. Bohr certainly believed the atomic system was an independently existing physical reality; he regarded physics as an attempt to gain empirical knowledge about those entities. His point was that we cannot describe these systems like classical physics described planets and billiard balls...because of Bohr's 'partial' agreement with the positivists in opposing classical realism, it is not unlikely that their influence was a factor in his reluctance to explore the ontological consequences of complementarity." (Pg. 25-26)

Many of Bohr's ideas were founded on positivist assumptions as well from what I can tell of my readings. That is certainly to be expected as he was first and foremost a scientist. Bohr strove for clarity and followed many different paths searching for it.

Chapter 2 fills the reader in on Bohr's philosophical background with a biographical sketch. He was born October 7, 1885 in Copenhagen. His family was well represented in the Danish educational circles, his father being a professor of physiology. He had an older brother, Harald, who carved out an international career in mathematics.

Folse writes: " Culturally Denmark stood midway between British and German traditions, allowing in a real sense a fortunate synthesis of British experimental science with the more formal, theoretical approach of the German Universities. In many ways, Bohr's philosophical temperament combined British influences stemming from the Lockean tradition of common sense empiricism with the typically German heritage of Kantian concerns with subjective and objective aspects of language. With respect to his philosophical development, Bohr's Danish heritage allowed him a certain freedom from the overruling 'schools' of idealism and materialism closely identified with various national traditions." (Pg. 32)

This reminds me a great deal of Pirsig's exploration of how Native American culture has permeated the culture of the white Europeans who settled here. Up until 1940, Denmark was a neutral country where the most intelligent minds in the world could meet and discuss static ideas in a Dynamic environment. Its also interesting that even today, the cutting edge research is being done in neutral countries.

The Como Papers

In 1912 Bohr produced a series of 3 papers which outlined his new theory of the atom and applied the postulates of his model to the formation of atomic spectra. Folse writes:

" Bohr's fundamental atomic theory appeared in three parts in 'The Philosophical Magazine' through the summer and fall of 1913. (Pg. 34) ...Through the ten years following his original 1913 papers Bohr continued with the help of his assistants to extend his theory of atomic structure by applying it to the entire periodical table. The last part of this great work was added in 1922. That year marked a fundamental change in the nature of Bohr's activities..." (Pg. 35)

" Bohr who had met with considerable criticism and lack of understanding, had at this time become one to whom all listened with reverence, so that the discussion about the lectures were rather concerned with whether Bohr had meant this or that, than the matter itself..." (Pg. 35)

Bohr was awarded the Nobel Prize in physics in December of 1922. Through the 1920s, he moved into his role as Director of Bohr's Institute at the University of Copenhagen. Complementarity was first revealed to a public audience in September, 1927, at a congress in Como, Italy. Folse writes:

"The delivered paper was far from finished form. Most of the audience were unimpressed, finding Bohr's argumentation far too 'philosophical' and including nothing new in physics..., however, throughout the fall of 1927 and the spring of 1928, the manuscript went through repeated rewritings. Finally it was ready for print by Easter of 1928."

These papers came to be called the Como Papers, and outlined Bohr's complementarity. Einstein's negative reaction was a grave disappointment to Bohr. Bohr made vital contributions to the theory of nuclear fission in 1939. In 1943 he was forced to flee the University of Copenhagen because of Nazi occupation.

After the war, Bohr became a world spokesman for nuclear and atomic physics. Throughout the last 25 years of his life, Bohr pursued the theme of complementarity as an epistemological lesson into a variety of fields. On November 18, 1962, Bohr died in his sleep while taking an afternoon nap.

Folse writes: " Bohr's manner of working was so distinctive that it has received much comment in the memoirs of those who worked with him. Typically, at the beginning of any project, Bohr started with the intention 'to write a little paper on it'. This would be accomplished by his dictating, often in a mixture of English, Danish and German, to a student or co-worker (or, in earlier days to his mother or wife) sentence by sentence the text of the paper to be. Sometimes there were long interruptions either for pondering what was to follow, or because Bohr had thought of something outside the theme which he had to tell me about." (Pg. 40, Oskar Klein- scribe/respondent for the Como Papers.)

As for Bohr's early philosophical influences, Folse writes:

" Thus I would conclude that if any philosopher other than Hoffling is to be given credit for having shaped complementarity, that credit belongs to William James. Through James the influence of Renouvier and Boutreaux, both of whom James greatly admired, could be said to have had a third hand on Bohr's thought, but it is likely that Bohr himself was never aware of this." (Pg. 51)

Chapter 3 is called 'Quantum Theory and the Description of Nature'. Folse explores Bohr's early thinking and the emergence of ideas that would lead to his complementarity. In this chapter, Folse follows Bohr's intellectual course from 1911 through 1927. Folse writes:

" Without exaggeration we may say that the framework of complementarity which Bohr proposed in 1927 was the result of work on atomic theory which he began as early as his doctoral dissertation in 1911...Bohr understood the fundamental task of atomic physics to be accounting for the properties of the chemical elements in terms of atomic structures....Because Bohr's revolutionary atomic theory required a dramatic break with classical theory, it is necessary to pause briefly to review how classical mechanics described the behavior of physical systems."

" As an empirical science, mechanics must of course develop a set of concepts for describing what will be observed in specific circumstances. Since motion is a change of position through time, for a science of mechanics what needs to be observed is only the position of bodies at instants of time, and the subsequent change of these positions through time relative to some reference system. Since the term 'body' refers to those objects whose behavior is described in mechanics, it follows by definition that bodies must possess the properties of position at each instant throughout a temporal duration, as well as the ability to change these positions. A 'physical system' may then be defined as any group (including possibly one) of such bodies." (Pg. 57)

" Mechanically the simplest possible system would be a single body system whose position could be represented as at rest or moving in a straight line at a constant velocity (uniform rectilinear motion) relative to some reference system...But of course mechanics cannot provide descriptions of only single body systems whose motion does not change. Real physical systems consist of more than one body and of bodies not at rest or in uniform rectilinear motion. The cause of departures from such motions is defined as a 'force'."

" Though not visible or impenetrable like material bodies, fields are defined as existing over a spatial region and manifesting a force at each point in that region. Thus in classical electrodynamics light and other forms of electromagnetic radiation can be theoretically represented as a wave disturbance moving in an electromagnetic field, commonly analogized to the motion of waves across the surface of a liquid." (Pg. 58)

" A mechanical description of the interactions between matter and radiation could be expressed in terms of an exchange of energy between bodies and the field...thus within the classical framework, the concepts of 'particle' and 'wave' refer to the theoretical representations through which one describes the behavior of matter and radiation."

This is how we can describe everyday reality. When the microcosm is examined however, the clear distinction between particle and wave no longer exists. It was discovered that both the particle and the wave theory worked equally well in describing the nature of the photon, where our notions of space and time no longer apply.

Folse writes: " Bohr's adaptation of the quantum postulate was completely an ad hoc addition to the classical framework with which it sharply conflicted.

" As long as the system remains closed, if we know the state parameters of each component in the system at some point in time, the 'initial conditions', then the law of mechanics, when applied to the state of the system, permit one to define the state of the system at any future time...The conservation principles for momentum and energy are thus what make possible defining the future states of a system by applying the classical principles to its state at some initial moment." (Pg. 59)

" From 1913 when Bohr published his atomic theory until 1925 when Heisenberg and Schrödinger succeeded in formulating consistent theories, Bohr relentlessly followed his general program of extending his early conception of atomic systems to explain all experimentally observed properties of the chemical atom. However, because of its internal inconsistencies he knew from the start that his theory could not provide the ultimately satisfactory description of atomic systems...and it remained a primary source of criticism for those who continued to regard Bohr's theory as solely a heuristic device for predicting a variety of phenomena, not a description of what really goes on inside atoms." (Pg. 66)

Throughout this period, Bohr stressed himself against taking his model as a literal picture of the atom. Bohr felt that a new framework for describing the atomic system should focus on the fact that quantum description of the interactions taking place at that level must tend to correspond to classical description. This so-called 'correspondence principle' allowed Bohr's theory to be expanded in many ways.

In 1924 Bohr wrote A.A. Michelson: "...it appears possible for a believer in the essential reality of the quantum theory to take a view which may harmonize with the essential reality of the wave conception...[and] it seems possible to connect the discontinuous processes occurring in the atoms with the continuous character of the radiation field in a somewhat more adequate way than hitherto perceived." (Pg. 76)

Harmonizing Quantum Description

During this time Bohr was searching for a way to harmonize the quantum description of the atom with a belief in essential reality of waves-in-a-field representation of radiation. The price to pay for this harmonizing would be the abandonment of strict energy conservation in individual interactions. If abandoning energy conservation was the answer, then the quantum description of the atom as changing its state discontinuously could be understood as a true representation of essential reality.

Comment from Doug Renselle: From what I can tell, energy conservation is a SOM nonstarter. Vacuum Energy (non)Space is so dense that it has enough energy in 1 cubic centimeter to make ~100,000,000,000,000,000,000,000,000,000,000,000,000,000 of our known universes, give or take a few zeroes. If we retain the concept of energy conservation, it, as SOM, must be kept in a small, subsumed portion of our new theory.

Bohr writes in late 1924: " After all, I believe that there may be more truth to the pseudo-mechanical treatment I tried in old times than one might perhaps think. In fact I believe we have here to do with an instructive example of the limitations in ordinary quantum theory rules...which affords an illustration of the necessity of giving up the strict validity of the general principles of conservation of energy and momentum." (Pg. 76)

However, 5 months after this was written, Walter Bothe and Hans Geiger of Germany demonstrated that energy was indeed strictly conserved in individual atomic interactions, thus disproving Bohr's proposal. On the very day he received news of this experiment, Bohr wrote:

"...it seems therefore that there is nothing else to do than to give our revolutionary efforts as honorable a funeral as possible...In fact I think that the possibility of describing these experiments without a radical departure from an ordinary space-and-time description is so remote that we may as well surrender at once and prepare ourselves for a coupling [i.e., an interaction] between the changes of state in distant atoms of the kind involved in the light quantum theory...I am thinking of all kinds of wild symbolic analogies." (Pg. 77)

Comment from Doug Renselle: See remarks above. My interpretation, given today's knowledge, is nonspace (DQ) can add to and subtract from total static (SQ) energy in space. Just prior to the big-bang quantum/Quality event, space was without static (SQ) energy or matter (they are identical by E=mc^2). Just after BB event, space became static (SQ) energy embedded in its parent, the isotropic dynamic energy we call nonspace or DQ. Today, supernovas and black holes, et al., add and subtract respectively to and from space's static (SQ) energy. If I am right, there is no way nonlocal space energy may be conserved. Clearly, it changes over time.

This gives an idea of Bohr's thoughts as he realized that harmony was not achieved because it was impossible to abandon strict energy conservation at the atomic level. First, since energy is conserved, the description of the interaction between matter and radiation could not represent radiation in these phenomena as a continuously changing field. Thus he suddenly took light-quantum theory much more seriously.

Doug Renselle: My description above is cosmological. But if you read Feynman, et al., they speak of virtual particles, tunneling, BECs, etc. Maewan Ho shows us that our muscles are coherent zero-entropy, non-thermalized energy consumers. Clearly, flexing your arm uses DQ/nonspace energy in a coherent process. Probably mind does too.

The other aspects of the classical ideal for a description (space-time) also became suspect. Consequently Bohr began to consider the possibility that theoretical representations of isolated atomic systems through the 'picture' of a system of particles moving on definable trajectories and of radiation in free space as a wave moving through a continuous electromagnetic field could not be understood in a classical sense of systems to be described.

Wave/Particle Dualism

Once Bohr realized that matter/energy conservation could not be given up, he also realized that the dualism of particles and waves would be something his new framework would have to deal with. It was during this time that Bohr had intense, almost daily discussions with a young assistant named Werner Heisenberg.

" ...it comes as no surprise that Heisenberg recalls in their discussions during the spring of 1926, Bohr reluctantly agreed for the first time to completely abandon any attempt to describe the atomic system in terms of 'visualizable' or pseudo-mechanical models. Here 'visualizable' clearly refers to 'space-time description' as classically understood. Nevertheless, it is probable that the parties to this agreement had rather different interpretations of what had been agreed to. On the one hand, Heisenberg apparently read their agreement as Bohr's endorsement for pursuing a purely mathematical theory that would ascribe properties only to observed phenomena resulting from interactions between atomic systems and radiation. On the other hand, Bohr characteristically read this agreement as endorsing a search for a revised understanding of how we use space and time concepts in picturing the behavior of atomic systems. For Heisenberg, this resolve helped to produce first matrix mechanics, then some twenty months later, the uncertainty principle. For Bohr, this agreement marked a major step on the road to complementarity." (Pg. 78)

Heisenberg saw Bohr's doubts about 'visualizable' models as implying that theoretical representations of the atom should proceed without attempting a space-time description of what is actually happening there. Heisenberg felt that the theory should focus on simply predicting results between radiation and atomic systems. Bohr was critical of Heisenberg's disregard for describing the physical aspect of the atom.

" 'I was completely shocked', recalled Heisenberg; 'I got quite furious because I thought I had something real and now they tried to explain it away'. So we had quite a heated discussion but at the end I came out with a slight victory...And I had for the first time the feeling that now I had been able to convince Bohr about something about which we had disagreed." (Pg. 79)

The Uncertainty Principle

In the summer of 1925, Heisenberg succeeded in formulating matrix calculus, the first expression of the 'new' quantum mechanics and a theory that completely eradicated any dependence on space-time descriptions of the atom. This success led Bohr to determine the exact point where the classical descriptive ideal broke down, and ultimately led to his theory of complementarity.

However, the highly abstract nature of matrix calculus seems to bar the way to finding any physical interpretation of the mathematical scheme. Thus Heisenberg's achievement led Bohr to analyze the relationship between the empirical classical system and the meaning of those same concepts within quantum representation of the atom.

When matrix mechanics appeared, both particle and wave representations seemed necessary to describe the full range of phenomena observed in the atomic system. However, if these theoretical representations applied to 'real' objects, then it would seem that these systems must have contradictory properties. Bohr put this inconsistency into the 'dualism' of particles and waves.

In 1927, Heisenberg presented his Uncertainty Principle, and in April of 1927 Heisenberg and Bohr finally reached an agreement. Bohr wrote to Einstein: "Heisenberg has asked that I send you a copy of the proofs he expects of a new article which he hopes will interest you...it has long been recognized how intimately the difficulties of quantum theory are connected with the concepts, or rather the words, which are used in the description of nature and all of which have their origin in classical theory...This situation permitted us by the limitations on our possibility of observations, in order to avoid all contradictions, as Heisenberg stresses...Through his new formulation we are given the possibility to harmonize the demand for conservation of energy with the wave theory of light, while in accord with the nature of description, the different sides of the problem never come into appearance simultaneously." (Pg. 97)

In this letter, Bohr outlines many of his arguments for complementarity which would lead to its birth. Bohr is looking for a "limitation" which would restrict the application of classical physical ideas when applied to quantum theory. At the same time, Bohr maintained that these classical notions must be maintained to describe the physical interactions which the new theory treated as an "interpretation of the experimental material".

Bohr felt that "because if the objects described by quantum mechanics as such waves and particles did in fact have independent reality in the ordinary physical sense, it would be possible to define classical mechanical states to them." (Pg. 111)

Bohr concludes that space/time coordination and causal description are complementary: "The very nature of the quantum theory thus forces us to regard the space-time co-ordination and the claim of causality, the union of which characterizes the classical theories, as complementary but exclusive features of the description, symbolizing the idealization of observation and definition." (Pg. 113)

The argument presented in the Como Papers remained Bohr's approach to complementarity throughout his life. This overview of complementarity is now complete, and you may continue the review by following the links at the bottom. Thanks for reading!

The Framework of Complementarity

Part 2 - Argument for Complementarity
Part 3 - Comments on Complementarity
Part 4 - Complementarity and the Uncertainty Principle
Part 5 - Refinement of Complementarity
Part 6 - Extension of Complementarity
Part 7 - The Nature of Empirical Knowledge
Part 8 - Complementarity and the Metaphysics of Quality

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