Yalçın Koç the Philosopher Physicist

I took classes from Yalçın Koç when I attended Boğaziçi University in Istanbul. He looked and acted very differently from all the other professors. He cut a distinguished figure on campus with his athletic build and a long red beard reminiscent of the 19′th century European philosophers. I knew that he was a famous mountain climber but I learned recently that he was a skilled carpenter and fisherman as well. He is known for his integrity in personal and academic life. He challenged the scientific dogmas. His was a lonely struggle against the establishment. In some sense his findings of the logical inconsistencies of Bell’s and Wigner’s arguments refuting local hidden variable theories of Quantum Mechanics were quixotic.

His insights on the “spin singlet state” are extremely important. The physics of the “spin singlet state” is key to the next paradigm shift in physics. We are approaching that tipping point and I predict a totally new understanding of elementary particle physics and cosmology will emerge in the next few decades.

Academic Life

He was born in 1950. He graduated from Middle East Technical University (Ankara) Physics Department in 1973 and started his Ph.D. studies at Istanbul University in 1974. He was a middle school mathematics teacher in the 1974-75 school year. He started teaching at Boğaziçi University in 1977 and received his Ph.D. in Philosophy from Istanbul University in 1978.

He became an associate professor at Boğaziçi University in 1982 and a full professor in 1988. He served as the head of the Philosophy Department, the dean of Science and Humanities and the director of Social Studies Institute at Boğaziçi University.

He was a visiting professor at the University of Pittsburgh in the 1978-79 academic year. He was in the faculty of Philosophy Department at Princeton University in 1983. He also served as a visiting professor at Boston University and at the International Centre for Theoretical Physics (ICTP) at Trieste.


His philosophy classes on Kant and Plato were legendary at Boğaziçi University. Other than Quantum Mechanics and the philosophy of Quantum Mechanics he was also considered a world expert in Kant, Plato, Frege and Freud. I took logic and metaphysics classes from him.

Resistance from Physics Establishment

A.Y. Özemre, in his book “Geçmiş Zaman Olur ki” talks about his friendship with Yalçın Koç and gives some background information about the drama that accompanied the publication of Koç’s latest papers. According to A.Y. Özemre, by 1988 Yalçın Koç had reached the conclusions which are summarized in his own words in the next section. He showed that Bell’s Inequalities were inconclusive. Since Bell’s Inequalities are the key supports of the Copenhagen Interpretation of Quantum Mechanics a resistance grew against Koç’s results. He presented these results at a workshop at the Ettore Majorana Center in the summer of 1989. His contributing papers, however, were removed from the conference proceedings.

According to A.Y. Özemre, Yalçın Koç accepted J.S. Bell’s invitation for coffee before his presentation. Bell asked him to withdraw his papers. Koç refused. Bell left the table abruptly in a rude manner and he was not present during Koç’s presentation. When Koç tried to publish these papers at Physics Letters which was his home since the beginning of his career, Physics Letters refused to publish them even though they gladly published his previous papers. Few years later the papers were finally accepted by Il Nouvo Cimento and published in 1992 and 1993. The abstracts of these papers can be seen in the “Selected Papers” section of this article.

Latest Paper

Yalçın Koç, “Implications of the Geometry of Quantum Mechanical Perfect Correlation Functions Concerning `Bell Theorem Without Inequalities’“, Turkish Studies in the History and Philosophy of Science, 59-68, Springer (2005), G. Irzık & G. Güzeldere (eds)

The introduction in this paper summarizes Koç’s key contributions.

“By analyzing a system of three or more correlated spin-1/2 particles, Greenberger, Horne, Shimony and Zeilinger claim that `the EPR program contradicts quantum mechanics even for the cases of perfect correlations. Greenberger et al. state that `this incompatibility with quantum mechanics is stronger than the one previously revealed for two-particle systems by Bell’s inequality, where no contradiction arises at the level of perfect correlations’ and conclude that their argument provides a proof of `Bell’s theorem without resorting to an ineqality’.

Bell’s arguments (Bell, 1964 and Bell, 1971 ) against local hidden variable theories proceed by means of inequalities; it is noted in (Koc,1992) that in these arguments Bell does not consider the geometrical (or, algebraic) properties of the quantum mechanical correlation function (for a system of spin-1/2 particles in the singlet state). It is shown in (Koc,1992) that due to the geometry (or, algebraic properties) of the quantum mechanical correlation function, Bell’s arguments in (Bell, 1964 and Bell, 1971 ) are inconclusive. In addition to this it is asserted in (Koc, 1993) that Wigner’s argument (Wigner, 1970) against local hidden variable theories is similarly inconclusive because of the geometrical (or, algebraic) properties of the quantum mechanical probability functions (for a system of spin-1/2 particles in the singlet state).”

Selected Papers

  • Yalçın Koç, “A non-completeness argument for quantum mechanics (analysis of the EPR paper)“,  Physics Letters A, Volume 79, Issue 1, p. 9-12 (1980)   Abstract: This paper aims at a clarification of the interrelations of the fundamental ideas in the EPR paper [2]. Through a logical analysis of the completeness condition and the physical reality criterion, we show how the premises of the EPR argument are obtained and explicate in what sense the conclusion that quantum mechanics is a non-complete theory follows.
  • Yalçın Koç, “A critical analysis of N. Bohr’s reply to the EPR argument“, Physics Letters A, Volume 81, Issue 8, p. 436-440. (1981)   Abstract: N. Bohr’s counter-argument to EPR assumes that the complementarity principle imposes a limitation on the types of predictions permissible in quantum theory, similar to the limitation imposed on the types of measurements by the Heisenberg uncertainty relation. Since this assumption has no quantum-theoretical justification, the EPR argument cannot be refuted on the basis of the complementarity principle.
  • Yalçın Koç, “A critical analysis of N. Bohr’s reply to the EPR argument revisited”, Physics Letters A, Volume 86, Issue 4, p. 217-220 (1981)  Abstract: It is shown that Koç’s argument does not claim an inconsistency with the wave packet reduction in Bohr’s reply to the EPR paper, as claimed by Madsen. Therefore, Madsen’s criticism is irrelevant to Koç’s argument.
  • Yalçın Koç, “Reconstruction of the past and inadequacy of the correspondence principle in quantum theory“, Physics Letters A, Volume 83, Issue 4, p. 151-154 (1981) , Abstract: A thought-experiment which was suggested by Einstein et al. is analyzed. It is shown that the time-energy uncertainty relation is incompatible with the time-localization of a macroscopic phenomenon. Based on this incompatibility, it is argued that the correspondence principle is inadequate.
  • Yalçın Koç, “Retrodiction of the transferred momentum in measurement and nonlocal determinism in quantum theory”, Physics Letters A, Volume 86, Issue 8, p. 401-404. (1981)   Abstract: According to quantum mechanics, the change in a measured variable, following a measurement of it, cannot be obtained. In the present paper, a thought-experiment is developed in which the change can be obtained by means of an extension of quantum mechanics. It is, then, claimed that quantum mechanics permits nonlocal determinism through state reduction, in terms of its extension.
  • Yalçın Koç, “Some remarks on the `no-interaction’ assumption in the Einstein-Podolsky-Rosen argument“,  Physics Letters A, Volume 90, Issue 9, p. 451-454. (1982)   Abstract: The “no-interaction” assumption of the Einstein-Podolsky-Rosen argument is analyzed. It is shown that this assumption can be explicitly embedded in the logical scheme of the EPR argument.
  • Yalçın Koç, “Reply to Lynch”, Physics Letters A, Volume 95, Issue 3-4, p. 133-134. (1983)   Abstract: Lynch’s alternate analysis of Koç’s thought-experiment is consistent with quantum mechanics. However, Lynch’s analysis does not resolve the paradox which is implied by Koç’s thought-experiment.
  • Yalçın Koç, “Local Expectation Value Function and Bell’s Inequalities”, Il Nouvo Cimento, 107B, p:961-971 (1992)   Abstract: A local hidden-variable theory is possible in view of quantum mechanics only if it satisfies bilinearity, symmetry and rotational invariance. If, however, a local hidden-variable theory satisfies all these algebraic properties, then Bell’s inequalities are not theorems of this theory. Therefore, violation of Bell’s inequalities by quantum mechanics is inconsequential for locality.
  • Yalçın Koç, “Wigner Inequality, Quantum-Mechanical Probability Functions and Hidden Variable Theories”, Il Nouvo Cimento, 108B, p:1115-1126 (1993)   Abstract: We investigate the algebraic properties of the quantum-mechanical singlet state probability functions and the algebraic conditions which these functions satisfy. We, then, argue that violation of Wigner’s inequality by quantum mechanics is not significant in deriving conclusions about locally realistic hidden-variable theories, in particular, and local realism, in general.

Selected Papers in Turkish

  • Yalçın Koç; “Kuantum Felsefesi” Tübitak Bilim ve Teknik dergisi, Sayı: 326, sayfa (22-29) Ocak-1995.
  • Yalçın Koç; “Kuantum Mekaniği Felsefesine Kısa Bir Bakış (1)”, Çağdaş Fizik, Bilimsel ve Mesleki Dergi, Sayı: 12, Kasım 1981.
  • Yalçın Koç; “Kuantum Mekaniği Felsefesine Bir Bakış (2)”, Çağdaş Fizik, Bilimsel ve Mesleki Dergi, Sayı: 13, Mayıs 1982.

Sudden Retirement

After the publication of his Il Nouvo Cimento papers in 1992 and 1993 he suddenly stopped academic studies and teaching and retired from the academic life and went into seclusion. He bought a small farm house on the Aegean cost. He now makes a living growing olives.

Most Recent Book

In his academic retirement Yalçın Koç published a book in Turkish titled “Anadolu Mayası: Türk kimliği üzerine bir inceleme”.  There is an interview in Turkish with Yalçın Koç that introduces the concepts discussed in the book. From my reading of the interview, I see signs of his transformation into a Sufi dervish.  Maybe he always had these leanings but he never mentioned them when he was my teacher. In the interview and in the introduction of his book he talks about the Unity of Being concept which is the main philosophical position of spirituality. This is how he introduces the book in Turkish: “Anadolu mayasının esası, cümle varlığın birliği ve kardeşliğidir. Toplum fikrini, ferdi bireyin de esası olan bu nokta itibariyle ele aldık. Bu meyanda dilin mahiyetini inceledik ve maya itibariyle Türkçe’nin önemini anlattık.” . I interpret this introduction as follows: while the essence of social unity is the Unity of Being (all creation is one and we are all brothers and sisters), in the case of difficult blending of  ethnic groups in Anatolia the Turkish language can be the strongest unifying factor.


About Suresh Emre

I have worked as a physicist at the Fermi National Accelerator Laboratory and the Superconducting Super Collider Laboratory. I am a volunteer for the Renaissance Universal movement. My main goal is to inspire the reader to engage in Self-discovery and expansion of consciousness.
This entry was posted in philosophy, physics and tagged , , , , , , . Bookmark the permalink.