The views of Niels Bohr on complementarity are examined, both in physics and in other fields. N. Bohr's opinions on the relationship between physics and biology are discussed in detail. It is shown that, over a number of years, Bohr viewed as complementary the study of organisms as atomic-molecular and as integral systems. Subsequently, owing to the development of molecular biology, Bohr rejected the idea of the complementarity in principle of the stated two types of studies. The current status of the physical theory of biological phenomena is examined, and the role of synergetics in this field is noted. The so-called antireductionism is criticized. It is shown that the views of contemporary eminent theoretical biologists reveal them to be unfamiliar with physics. The very important role of physics in the further development of biology and its practical applications is emphasized.
The views of Niels Bohr on complementarity are examined, both in physics and in other fields. N. Bohr's opinions on the relationship between physics and biology are discussed in detail. It is shown that, over a number of years, Bohr viewed as complementary the study of organisms as atomic-molecular and as integral systems. Subsequently, owing to the development of molecular biology, Bohr rejected the idea of the complementarity in principle of the stated two types of studies. The current status of the physical theory of biological phenomena is examined, and the role of synergetics in this field is noted. The so-called antireductionism is criticized. It is shown that the views of contemporary eminent theoretical biologists reveal them to be unfamiliar with physics. The very important role of physics in the further development of biology and its practical applications is emphasized.
In this study Arun Bala examines the implications that Niels Bohr’s principle of complementarity holds for fields beyond physics. Bohr, one of the founding figures of modern quantum physics, argued that the principle of complementarity he proposed for understanding atomic processes has parallels in psychology, biology, and social science, as well as in Buddhist and Taoist thought. But Bohr failed to offer any explanation for why complementarity might extend beyond physics, and his claims have been widely rejected by scientists as empty speculation. Scientific scepticism has only been reinforced by the naïve enthusiasm of postmodern relativists and New Age intuitionists, who seize upon Bohr’s ideas to justify anti-realist and mystical positions. Arun Bala offers a detailed defence of Bohr’s claim that complementarity has far-reaching implications for the biological and social sciences, as well as for comparative philosophies of science, by explaining Bohr’s parallels as responses to the omnipresence of grown properties in nature.
On August 15, 1932 Niels Bohr gave opening address of International Congress on Therapy held in Copenhagen. Bohr's title was Light and Life, and his purpose was to draw attention to epistemological implications for life sciences of fundamental changes that quantum theory had brought to conception of natural law (Bohr 1933). He thought that these changes, which extend to very idea of nature of scientific explanation, were important not only for a full appreciation of new situation brought to physics by quantum theory. According to Bohr, these developments had also created an entirely new background for viewing problems of biology, especially as concerns our views on position of living organisms in realm of natural science. In particular, Bohr proposed that notion of complementarity, which he had first presented 5 years earlier at International Congress of Physics in Como, relevant also for physiological and psychological aspects of life. Bohr began his address by stating what nowadays stigmatized as reductionist credo, namely that subtle character of riddle of life notwithstanding, any scientific explanation of biological phenomena necessarily must consist of reducing description of more complex phenomena to that of simpler ones. But, Bohr continued, discovery of an essential limitation of mechanical description of natural phenomena, as revealed by recent development of atomic theory, has lent new interest to old problem of how far program of reductive biological explanations can be carried. Bohr then presented a brief historical account of rise of quantum theory in connection with study of light, which he thought is perhaps least complex of all physical phenomena. Yet, it turned out that despite its lack of complexity, phenomenon of light cannot be given a coherent mechanical explanation, inasmuch as from viewpoint of classical physical theories, the quantum of action . . . must be considered as an irrational notion. The spatial continuity of light propagation, on one hand, and atomicity of light effects on other hand, must, therefore, be considered as complementary aspects of one reality, in sense that each expresses an important feature of phenomena of light. Those aspects are complementary, because, although they are conceptually irreconcilable from a mechanical point of view, they can never be shown to be in direct, or empirical, contradiction. The reason for this that any closer analysis of either wave aspect or particle aspect of light demands mutually exclusive observational arrangements.
On August 15, 1932 Niels Bohr gave opening address of International Congress on Therapy held in Copenhagen. Bohr's title was Light and Life, and his purpose was to draw attention to epistemological implications for life sciences of fundamental changes that quantum theory had brought to conception of natural law (Bohr 1933). He thought that these changes, which extend to very idea of nature of scientific explanation, were important not only for a full appreciation of new situation brought to physics by quantum theory. According to Bohr, these developments had also created an entirely new background for viewing problems of biology, especially as concerns our views on position of living organisms in realm of natural science. In particular, Bohr proposed that notion of complementarity, which he had first presented 5 years earlier at International Congress of Physics in Como, relevant also for physiological and psychological aspects of life. Bohr began his address by stating what nowadays stigmatized as reductionist credo, namely that subtle character of riddle of life notwithstanding, any scientific explanation of biological phenomena necessarily must consist of reducing description of more complex phenomena to that of simpler ones. But, Bohr continued, discovery of an essential limitation of mechanical description of natural phenomena, as revealed by recent development of atomic theory, has lent new interest to old problem of how far program of reductive biological explanations can be carried. Bohr then presented a brief historical account of rise of quantum theory in connection with study of light, which he thought is perhaps least complex of all physical phenomena. Yet, it turned out that despite its lack of complexity, phenomenon of light cannot be given a coherent mechanical explanation, inasmuch as from viewpoint of classical physical theories, the quantum of action . . . must be considered as an irrational notion. The spatial continuity of light propagation, on one hand, and atomicity of light effects on other hand, must, therefore, be considered as complementary aspects of one reality, in sense that each expresses an important feature of phenomena of light. Those aspects are complementary, because, although they are conceptually irreconcilable from a mechanical point of view, they can never be shown to be in direct, or empirical, contradiction. The reason for this that any closer analysis of either wave aspect or particle aspect of light demands mutually exclusive observational arrangements.
SUMMARY. — This paper emphasizes the evolution of complementarity, in Niels Bohr's successive formulations of this idea, from 1927 to 1939, despite little, if any change in the definition of the concept with time. In the Como lecture, in 1927, Bohr introduced the idea of « complementary descriptions » in a problematic, polemical way. Against Schrödinger' s interpretation, he stressed the « irrationality » inherent in the quantum postulate. In 1935, Bohr again used complementarity polemically, in his reply to Einstein-Podolsky-Rosen. But far from intending it to convey irrationality this time, he meant to use it instead to prove that quantum mechanics is a complete theory. Finally, I will take up Bohr's attempts to apply complementarity to fundamental problems in biology, psychology, sociology, and so forth. I will argue that the introduction of complementarity outside physics was not motivated by an imperialist ambition of the Copenhagen School, but rather inspired by Bohr's own personal philosophy.
The so-called “orthodox” interpretation of quantum physics attributed to Niels Bohr is commonly regarded as abandoning realism. I have already opposed this view elsewhere (Folse 1985) but partially in response to criticism of my position (Shimony 1985), here I propose to relate Bohr’s realism to recent contributions to the realism debate given by Hacking (1983), Cartwright (1983), and Ellis (1985). Specifically, I argue that Bohr’s complementarity viewpoint requires a causal entity realism. Furthermore, labeling Bohr an anti-realist with respect to theories is misleading because it assumes the correspondence theory of truth that Bohr holds quantum theory forces us to reject. Although there are many realist views, I take the root of realism to be the quest for knowledge about the reality producing the phenomena we experience. It is realism in this sense that Bohr defended and that makes science significant to metaphysics.