The evolution of the complementarity meme in quantum physics

A brief history of the evolution of the

“complementarity” meme in quantum physics

Christopher B. Germann (2019)

It was a pivotal turning point for physics when Nils Bohr first introduced his formulation of

the idea of complementarity to his numerous colleagues. This historical event took place at the

International Congress of Physics in September 1927 in Como, Italy and the world’s most em-

inent physicists were in the audience: Max Born, Enrico Fermi, John von Neumann, Wolfgang

Pauli, Max Planck, Werner Heisenberg, Eugene Wigner, Louis de Broglie, to name just a few.

However, Albert Einstein was noticeably absent for some unbeknown reason (Holton, 1970).

The idea of complementarity fundamentally transformed physics. One of the crucial points

Bohr emphasised concerned “the impossibility of any sharp separation between the behaviour

of atomic objects and the interaction with the measuring instruments which serve to define the

conditions under which the phenomena appear” (Bohr, 1961).

In a theme issue of the journal DIALECTICA edited by Wolfgang Pauli and published in 1948

compiles various seminal papers on complementarity by eminent physicists. Bohr also contrib-

uted an article to this special issue entitled “On the notions of causality and complementarity”

(Bohr, 1948) in which he discusses the dialectic complementarity mode of description and the

impossibility to objectively separate “between behaviour of the atomic objects and their inter-

action with the measuring instruments defining the conditions under which the phenomena

appear.”

(Bohr, 1948, p.312).

Interestingly, Bohr was a cousin of the famous Danish psychologist Edgar Rubin who is famous

for his eponymous Rubin’s Vase (Rubin, 1915), see Figure 3. This ambiguous visual stimulus

is today still widely used in research on bistable perception in psychology and neuroscience

(e.g., Hasson, Hendler, Bashat, & Malach, 2001; Qiu et al., 2009; Wang et al., 2017). Interest-

ingly from a history of science point of view, it was Rubin who introduced Bohr to the concept

of complementarity. Both were members of the club “Ekliptika” (see Figure 4). Rubin in turn

adopted the idea from the writings of the late William James who wrote about complementarity

in Chapter 8 in his timeless classic “Principles of Psychology” (James, 1890). While Rubin

focused on perceptual complementarity, Bohr was primarily concerned with epistemological

complementarity (Pind, 2014) and much of his later writings were concerned with this topic.

Hence, from this historical vantage point, the quantum cognition paradigm is bringing the

meme of complementarity (which originated in psychology and spread to change the funda-

mentals of physics) back to its roots.

Figure 1. Rubin’s Vase: A bistable percept as a visual example of complementarity-coupling

between foreground and background.

In an interview

with Thomas Kuhn

which took place in 1962, Bohr stated:

I was a close friend of Rubin, and, therefore, I read actually the work of William

James. William James is really wonderful in the way that he makes it clear—I think I read the

book, or a paragraph, called —. No, what is that called?—It is called ‘‘The Stream of

Thoughts,’’ where he in a most clear manner shows that it is quite impossible to analyse things

in terms of—I don’t know what one calls them, not atoms. I mean simply, if you have some

things…they are so connected that if you try to separate them from each other, it just has noth-

ing to do with the actual situation. I think that we shall really go into these things, and I know

something about William James. That is coming first up now. And that was because I spoke to

people about other things, and then Rubin advised me to read something of William James,

and I thought he was most wonderful.”

The significance of complementarity beyond the domain of physics has been discussed in

greater detail by Atmanspacher, Römer, & Walach (2002). The complementarity principle is

closely related to the concepts of entanglement, superposition, noncommutativity, and the stip-

ulated collapse of the wave-function. In fact, “quantum noncommutativity can be regarded as

a mathematical expression of the complementarity principle” (Plotnitsky, 2016).

The full transcript of the interview is available on the homepage of the American Institute of Physics under the

following URL: https://www.aip.org/history-programs/niels-bohr-library/oral-histories/4517-5

Interestingly, Thomas Kuhn made use of ambiguous visual stimuli in his own work to demonstrate the percep-

tual change that accompanies a paradigm-shift. He used the “duck-rabbit” (a bistable figure created by the psy-

chophysicist Joseph Jastrow and popularised by Ludwig Wittgenstein), as a visual metaphor to illustrate that a

paradigm-shift can cause the cogniser to perceive the same information in a completely different way (see Ap-

pendix A7 for an example and a discussion). The complementarity principle was thus utilised in the context of

the perception of seemingly incompatible scientific paradigms. That is, it illustrates the Kuhnian concept of in-

commensurability which is of great relevance for the discussion of the perceived dichotomy between mind and

matter. Moreover, the inability to entertain multiple viewpoints simultaneously is of great pertinence for discus-

sion of interdisciplinarity, e.g., psychology and physics (mind/matter) can be regarded as complementary.

Figure 2. Photograph of Niels Bohr and Edgar Rubin as members of the club “Ekliptika” (Royal

Library of Denmark).

From left to right: Harald Bohr, Poul Nørlund, Edgar Rubin, Niels Bohr and Niels-Erik Nør-

lund (Royal Library, Copenhagen

When Bohr received the prestigious Danish “Order of the Elephant” (a distinction normally

reserved for royalty) he emphasised the importance of the complementarity principle. Bohr

choose to wear the ancient Chinese Yin & Yang symbol ☯ on his coat of arms together with

the Latin slogan “Contraria sunt complementa” (opposites are complementary), see Figure 5.

The resemblance between the Yin and Yang symbol and the ambiguous figures studied by

Rubin is remarkable. Moreover, various interdisciplinary scholars maintain that nonduality be-

tween mind and matter (psyche vs. physis, percipient vs. perceived, observer vs. observed,

inner vs. outer, etc. pp.) is a fundamental pillar of Advaita Vedānta, Mahayana/Madhyamaka

Buddhism, and Neo-Platonism (e.g., Plotinus), inter alia.

Associated URL of the file in the digital Royal Library of Denmark: http://www.kb.dk/im-

ages/billed/2010/okt/billeder/object73704/da/

Figure 3. Escutcheon worn by Niels Bohr during the award of the “Order of the Elephant”.

In 1947 Bohr was awarded with the “Order of the Elephant” (Elefantordenen), Demarks

highest-ranked accolade. Bohr chose a “coat of arms” which was embroidered with the Bud-

dhistic Yin & Yang symbol on order to emphasise the centrality of nonduality and comple-

mentarity

in his work on quantum physics. Chinese Buddhism is an offshoot of early Hindu-

ism, the womb of the ancient nondual philosophical school of Advaita Vedānta

which is

based on a highly sophisticated and extensive logic system (Gabbay & Guenthner, 2014;

Nicholson, 2007).

Interestingly from both a visual science and physics point of view, when light interacts with the eye the wave-

particle duality resolves, that is, observation collapses the superpositional state into a determinate eigenvalue. In

this context, Einstein wrote the following on the complementarity of physical descriptions: “It seems as though

we must use sometimes the one theory and sometimes the other, while at times we may use either. We are faced

with a new kind of difficulty. We have two contradictory pictures of reality; separately neither of them fully ex-

plains the phenomena of light, but together they do.” (Einstein & Infeld, 1938, p. 278)

According to Advaita Vedānta, consciousness and material reality do not exist in separation. This schism, is an

illusion or Māyā (Bhattacharji, 1970; Dabee, 2017). That is, the subject/object divide is also part of Māyā or

“mere appearance”. Beyond the perceived duality is what quantum physicist John Hagelin calls “the unified

field” or “string field”– pure abstract self-awareness which forms the nondual basis for all of existence, material

and immaterial (Hagelin & Hagelin, 1981).

Nils Bohr writes:

“Altogether, the approach towards the problem of explanation that is embodied in the notion

of complementarity suggests itself in our position as conscious beings and recalls forcefully

the teaching of ancient thinkers that, in the search for a harmonious attitude towards life, it

must never be forgotten that we ourselves are both actors and spectators in the drama of

existence.”

(Bohr, 1950, p.54).

Applied to the dichotomy between science and mysticism described by William James (see

introduction), the complementarity principle entails that that the seemingly polar oppiste “sci-

ence versus mysticism” are not mutually exclusive but both necessary to complete the circle

of human understanding (Hofmann, 1994).

References

Atmanspacher, H., Römer, H., & Walach, H. (2002). Weak Quantum Theory:

Complementarity and Entanglement in Physics and Beyond. Foundations of Physics,

32(3), 379–406. https://doi.org/10.1023/A:1014809312397

Bohr, N. (1961). Essays 1958-1962 on Atomic Physics and human knowledge. The

Philosophical writings of Niels Bohr.

Dabee, R. (2017). Māyā - Avidyā in Advaita : Historical Importance and Philosophical

Relevance. Holistic Vision and Integral Living, VIII(May), 87–104.

Einstein, A., & Infeld, L. (1938). The Evolution of Physics. The Cambridge Library of

Modern Science. https://doi.org/10.1119/1.1987055

Gabbay, D. M., & Guenthner, F. (2014). Handbook of philosophical logic. Handbook of

Philosophical Logic (Vol. 17). https://doi.org/10.1007/978-94-007-6600-6

Hagelin, J., & Hagelin, J. S. (1981). Is Consciousness the Unified Field ? A Field Theorist ’ s

Perspective. Nuclear Physics.

Hasson, U., Hendler, T., Bashat, D. Ben, & Malach, R. (2001). Vase or Face? A Neural

Correlate of Shape-Selective Grouping Processes in the Human Brain. Journal of

Cognitive Neuroscience, 13(6), 744–753. https://doi.org/10.1162/08989290152541412

Hofmann, A. (1994). Naturwissenschaft & mystische Welterfahrung. Pieper’s

Medienexperimente.

Holton, G. (1970). The roots of complementarity. Daedalus, 117(3), 151–197. Retrieved

from http://www.jstor.org/stable/10.2307/20023980

James, W. (1890). The principles of psychology. New York Holt, 1, 697.

https://doi.org/10.1037/10538-000

Nicholson, A. J. (2007). Reconciling dualism and non-dualism: Three arguments in

Vijñānabhiksu’s Bhedābheda Vedānta. Journal of Indian Philosophy, 35(4), 371–403.

https://doi.org/10.1007/s10781-007-9016-6

Pind, J. L. (2014). Edgar Rubin and Psychology in Denmark. https://doi.org/10.1007/978-3-

319-01062-5

Plotnitsky, A. (2016). Bohr, Heisenberg, Schrödinger, and the Principles of Quantum

Mechanics. In The Principles of Quantum Theory, From Planck’s Quanta to the Higgs

Boson (pp. 51–106). Cham: Springer International Publishing.

https://doi.org/10.1007/978-3-319-32068-7_2

Qiu, J., Wei, D., Li, H., Yu, C., Wang, T., & Zhang, Q. (2009). The vase-face illusion seen by

the brain: An event-related brain potentials study. International Journal of

Psychophysiology, 74(1), 69–73. https://doi.org/10.1016/j.ijpsycho.2009.07.006

Rubin, E. (1915). Synsoplevede figurer: studier i psykologisk analyse. Første Del.

Copenhagen: Gyldendalske Boghandel, Nordisk Forlag.

Wang, X., Sang, N., Hao, L., Zhang, Y., Bi, T., & Qiu, J. (2017). Category selectivity of

human visual cortex in perception of Rubin Face-Vase illusion. Frontiers in Psychology,

8(SEP). https://doi.org/10.3389/fpsyg.2017.01543

A brief history of the evolution of the “complementarity” meme in quantum physics Christopher B. Germann (2019) It was a pivotal turning point for physics when Nils Bohr first introduced his formulation of the idea of complementarity to his numerous colleagues. This historical event took place at the International Congress of Physics in September 1927 in Como, Italy and the world’s most em-inent physicists were in the audience: Max Born, Enrico Fermi, John von Neumann, Wolfgang Pauli, Max Planck, Werner Heisenberg, Eugene Wigner, Louis de Broglie, to name just a few. However, Albert Einstein was noticeably absent for some unbeknown reason (Holton, 1970). The idea of complementarity fundamentally transformed physics. One of the crucial points Bohr emphasised concerned “the impossibility of any sharp separation between the behaviour of atomic objects and the interaction with the measuring instruments which serve to define the conditions under which the phenomena appear” (Bohr, 1961). In a theme issue of the journal DIALECTICA edited by Wolfgang Pauli and published in 1948 compiles various seminal papers on complementarity by eminent physicists. Bohr also contrib-uted an article to this special issue entitled “On the notions of causality and complementarity” (Bohr, 1948) in which he discusses the dialectic complementarity mode of description and the impossibility to objectively separate “between behaviour of the atomic objects and their inter-action with the measuring instruments defining the conditions under which the phenomena appear.” (Bohr, 1948, p.312). Interestingly, Bohr was a cousin of the famous Danish psychologist Edgar Rubin who is famous for his eponymous Rubin’s Vase (Rubin, 1915), see Figure 3. This ambiguous visual stimulus is today still widely used in research on bistable perception in psychology and neuroscience (e.g., Hasson, Hendler, Bashat, & Malach, 2001; Qiu et al., 2009; Wang et al., 2017). Interest-ingly from a history of science point of view, it was Rubin who introduced Bohr to the concept of complementarity. Both were members of the club “Ekliptika” (see Figure 4). Rubin in turn adopted the idea from the writings of the late William James who wrote about complementarity in Chapter 8 in his timeless classic “Principles of Psychology” (James, 1890). While Rubin focused on perceptual complementarity, Bohr was primarily concerned with epistemological complementarity (Pind, 2014) and much of his later writings were concerned with this topic. Hence, from this historical vantage point, the quantum cognition paradigm is bringing the meme of complementarity (which originated in psychology and spread to change the funda-mentals of physics) back to its roots. Bildergebnis für rubins vase Figure 1. Rubin’s Vase: A bistable percept as a visual example of complementarity-coupling between foreground and background. In an interview1 with Thomas Kuhn2 which took place in 1962, Bohr stated: 1 The full transcript of the interview is available on the homepage of the American Institute of Physics under the following URL: https://www.aip.org/history-programs/niels-bohr-library/oral-histories/4517-5 2 Interestingly, Thomas Kuhn made use of ambiguous visual stimuli in his own work to demonstrate the percep-tual change that accompanies a paradigm-shift. He used the “duck-rabbit” (a bistable figure created by the psy-chophysicist Joseph Jastrow and popularised by Ludwig Wittgenstein), as a visual metaphor to illustrate that a paradigm-shift can cause the cogniser to perceive the same information in a completely different way (see Ap-pendix A7 for an example and a discussion). The complementarity principle was thus utilised in the context of the perception of seemingly incompatible scientific paradigms. That is, it illustrates the Kuhnian concept of in-commensurability which is of great relevance for the discussion of the perceived dichotomy between mind and matter. Moreover, the inability to entertain multiple viewpoints simultaneously is of great pertinence for discus-sion of interdisciplinarity, e.g., psychology and physics (mind/matter) can be regarded as complementary. I was a close friend of Rubin, and, therefore, I read actually the work of William James. William James is really wonderful in the way that he makes it clear—I think I read the book, or a paragraph, called —. No, what is that called?—It is called ‘‘The Stream of Thoughts,’’ where he in a most clear manner shows that it is quite impossible to analyse things in terms of—I don’t know what one calls them, not atoms. I mean simply, if you have some things…they are so connected that if you try to separate them from each other, it just has noth-ing to do with the actual situation. I think that we shall really go into these things, and I know something about William James. That is coming first up now. And that was because I spoke to people about other things, and then Rubin advised me to read something of William James, and I thought he was most wonderful.” The significance of complementarity beyond the domain of physics has been discussed in greater detail by Atmanspacher, Römer, & Walach (2002). The complementarity principle is closely related to the concepts of entanglement, superposition, noncommutativity, and the stip-ulated collapse of the wave-function. In fact, “quantum noncommutativity can be regarded as a mathematical expression of the complementarity principle” (Plotnitsky, 2016). C:\Users\cgermann\Downloads\ke009883.jpg Figure 2. Photograph of Niels Bohr and Edgar Rubin as members of the club “Ekliptika” (Royal Library of Denmark). From left to right: Harald Bohr, Poul Nørlund, Edgar Rubin, Niels Bohr and Niels-Erik Nør-lund (Royal Library, Copenhagen3). 3 Associated URL of the file in the digital Royal Library of Denmark: http://www.kb.dk/im-ages/billed/2010/okt/billeder/object73704/da/ When Bohr received the prestigious Danish “Order of the Elephant” (a distinction normally reserved for royalty) he emphasised the importance of the complementarity principle. Bohr choose to wear the ancient Chinese Yin & Yang symbol . on his coat of arms together with the Latin slogan “Contraria sunt complementa” (opposites are complementary), see Figure 5. The resemblance between the Yin and Yang symbol and the ambiguous figures studied by Rubin is remarkable. Moreover, various interdisciplinary scholars maintain that nonduality be-tween mind and matter (psyche vs. physis, percipient vs. perceived, observer vs. observed, inner vs. outer, etc. pp.) is a fundamental pillar of Advaita Vedanta, Mahayana/Madhyamaka Buddhism, and Neo-Platonism (e.g., Plotinus), inter alia. https://upload.wikimedia.org/wikipedia/commons/7/75/Niels_David_Henrik_Bohr_-_Coat_of_arms_in_Frederiksborg_Castle_Church.jpg \\scandle.plymouth.ac.uk\cgermann\phd thesis working versions\coat_of_arms_of_niels_bohr_svg.png Figure 3. Escutcheon worn by Niels Bohr during the award of the “Order of the Elephant”. In 1947 Bohr was awarded with the “Order of the Elephant” (Elefantordenen), Demarks highest-ranked accolade. Bohr chose a “coat of arms” which was embroidered with the Bud-dhistic Yin & Yang symbol on order to emphasise the centrality of nonduality and comple-mentarity4 in his work on quantum physics. Chinese Buddhism is an offshoot of early Hindu-ism, the womb of the ancient nondual philosophical school of Advaita Vedanta5 which is based on a highly sophisticated and extensive logic system (Gabbay & Guenthner, 2014; Nicholson, 2007). 4 Interestingly from both a visual science and physics point of view, when light interacts with the eye the wave-particle duality resolves, that is, observation collapses the superpositional state into a determinate eigenvalue. In this context, Einstein wrote the following on the complementarity of physical descriptions: “It seems as though we must use sometimes the one theory and sometimes the other, while at times we may use either. We are faced with a new kind of difficulty. We have two contradictory pictures of reality; separately neither of them fully ex-plains the phenomena of light, but together they do.” (Einstein & Infeld, 1938, p. 278) 5According to Advaita Vedanta, consciousness and material reality do not exist in separation. This schism, is an illusion or Maya (Bhattacharji, 1970; Dabee, 2017). That is, the subject/object divide is also part of Maya or “mere appearance”. Beyond the perceived duality is what quantum physicist John Hagelin calls “the unified field” or “string field”– pure abstract self-awareness which forms the nondual basis for all of existence, material and immaterial (Hagelin & Hagelin, 1981). Nils Bohr writes: “Altogether, the approach towards the problem of explanation that is embodied in the notion of complementarity suggests itself in our position as conscious beings and recalls forcefully the teaching of ancient thinkers that, in the search for a harmonious attitude towards life, it must never be forgotten that we ourselves are both actors and spectators in the drama of existence.” (Bohr, 1950, p.54). Applied to the dichotomy between science and mysticism described by William James (see introduction), the complementarity principle entails that that the seemingly polar oppiste “sci-ence versus mysticism” are not mutually exclusive but both necessary to complete the circle of human understanding (Hofmann, 1994). References Atmanspacher, H., Römer, H., & Walach, H. (2002). Weak Quantum Theory: Complementarity and Entanglement in Physics and Beyond. Foundations of Physics, 32(3), 379–406. https://doi.org/10.1023/A:1014809312397 Bohr, N. (1961). Essays 1958-1962 on Atomic Physics and human knowledge. The Philosophical writings of Niels Bohr. Dabee, R. (2017). Maya - Avidya in Advaita.: Historical Importance and Philosophical Relevance. Holistic Vision and Integral Living, VIII(May), 87–104. Einstein, A., & Infeld, L. (1938). The Evolution of Physics. The Cambridge Library of Modern Science. https://doi.org/10.1119/1.1987055 Gabbay, D. M., & Guenthner, F. (2014). Handbook of philosophical logic. Handbook of Philosophical Logic (Vol. 17). https://doi.org/10.1007/978-94-007-6600-6 Hagelin, J., & Hagelin, J. S. (1981). Is Consciousness the Unified Field.? A Field Theorist ’ s Perspective. Nuclear Physics. Hasson, U., Hendler, T., Bashat, D. Ben, & Malach, R. (2001). Vase or Face? A Neural Correlate of Shape-Selective Grouping Processes in the Human Brain. Journal of Cognitive Neuroscience, 13(6), 744–753. https://doi.org/10.1162/08989290152541412 Hofmann, A. (1994). Naturwissenschaft & mystische Welterfahrung. Pieper’s Medienexperimente. Holton, G. (1970). The roots of complementarity. Daedalus, 117(3), 151–197. Retrieved from http://www.jstor.org/stable/10.2307/20023980 James, W. (1890). The principles of psychology. New York Holt, 1, 697. https://doi.org/10.1037/10538-000 Nicholson, A. J. (2007). Reconciling dualism and non-dualism: Three arguments in Vijñanabhiksu’s Bhedabheda Vedanta. Journal of Indian Philosophy, 35(4), 371–403. https://doi.org/10.1007/s10781-007-9016-6 Pind, J. L. (2014). Edgar Rubin and Psychology in Denmark. https://doi.org/10.1007/978-3-319-01062-5 Plotnitsky, A. (2016). Bohr, Heisenberg, Schrödinger, and the Principles of Quantum Mechanics. In The Principles of Quantum Theory, From Planck’s Quanta to the Higgs Boson (pp. 51–106). Cham: Springer International Publishing. https://doi.org/10.1007/978-3-319-32068-7_2 Qiu, J., Wei, D., Li, H., Yu, C., Wang, T., & Zhang, Q. (2009). The vase-face illusion seen by the brain: An event-related brain potentials study. International Journal of Psychophysiology, 74(1), 69–73. https://doi.org/10.1016/j.ijpsycho.2009.07.006 Rubin, E. (1915). Synsoplevede figurer: studier i psykologisk analyse. Første Del. Copenhagen: Gyldendalske Boghandel, Nordisk Forlag. Wang, X., Sang, N., Hao, L., Zhang, Y., Bi, T., & Qiu, J. (2017). Category selectivity of human visual cortex in perception of Rubin Face-Vase illusion. Frontiers in Psychology, 8(SEP). https://doi.org/10.3389/fpsyg.2017.01543