Abstract Niels Bohr is standardly read as an instrumentalist or a cautious anti-realist. By way of a rational reconstruction, I argue that his philosophy of experiment advances a transcendental account of the conditions under which physical properties can count as objective at all. On this view, complementarity constrains the forms of description through which physical properties become determinate and communicable. Existing transcendental readings stop at this point; I argue that his philosophy of experiment contains the resources to go further. Objectivity is not merely constituted by such conditions but physically enacted through the observer’s choice of experimental context. This means moving beyond representational and observer-independent forms of realism and adopting a participatory realism in which objectivity is reconceived as the intersubjective stability across observers who experiment (and thus experience) within a shared mode of possible experience. The slogan ‘to be is to measure’ is not defended as an ontological thesis but as shorthand for the claim that physical properties become determinate only within experimental contexts that embodied observers of a particular class enact and share.
Abstract Niels Bohr is standardly read as an instrumentalist or a cautious anti-realist. By way of a rational reconstruction, I argue that his philosophy of experiment advances a transcendental account of the conditions under which physical properties can count as objective at all. On this view, complementarity constrains the forms of description through which physical properties become determinate and communicable. Existing transcendental readings stop at this point; I argue that his philosophy of experiment contains the resources to go further. Objectivity is not merely constituted by such conditions but physically enacted through the observer’s choice of experimental context. This means moving beyond representational and observer-independent forms of realism and adopting a participatory realism in which objectivity is reconceived as the intersubjective stability across observers who experiment (and thus experience) within a shared mode of possible experience. The slogan ‘to be is to measure’ is not defended as an ontological thesis but as shorthand for the claim that physical properties become determinate only within experimental contexts that embodied observers of a particular class enact and share.
Quantum mechanics reconfigures classical assumptions about objectivity by showing that physical description cannot be separated from the processes through which phenomena become intelligible. While Niels Bohr is often read as an instrumentalist or cautious anti-realist, this paper argues instead that his account of measurement advances a transcendental analysis of the conditions under which physical properties can count as objective at all. On this reading, complementarity is not a limit on access to an underlying reality, but a constraint on the forms of description through which physical properties become determinate and communicable. Drawing on a neo-Kantian perspective, I argue that objectivity in quantum theory is neither representational nor observer-independent but is realised through participatory conditions that anchor physical meaning within shared spatio-temporal and causal frameworks. The slogan ‘to be is to measure’ is defended as shorthand for the claim that objective physical properties are not revealed as pre-existing features of nature but arise only within experimental contexts that disclose them as intelligible objects within a shared mode of possible experience.
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.
Now that Bohr's philosophy of quantum physics has been surveyed in detail, it is time to provide a general description of his philosophy that illuminates the details. The question which I wish to address, then is: what is the general philosophy, or philosophical point of view, that underlies Bohr's philosophy of physics? Can his philosophy be neatly categorised in terms of any well known philosophical position? Apropos his philosophy of physics in particular, the question of primary interest is: to what extent, if any, is Bohr's philosophy of physics realist? No simple answer to this question can be given: indeed, certain realist and non-realist components are subtly interwoven in his philosophy, and to unravel them we shall need a fairly refined conception of what constitutes a realist interpretation of physics. Realism in the interpretation of physics The basis of realism is the view that statements of a certain class predicate properties of real objects, the truth-values of these statements being determined by reality as it is independently of how it appears to us to be. This notion is captured in the following characterisation of what constitutes the adoption of a realist interpretation of a physical theory.
Niels Bohr, considered one of the fathers of quantum mechanics, formulated a complex interpretation \nof quantum mechanics that guided his understanding of quantum experiments. The contemporary dispute \nbetween realism and anti-realism, the two main approaches to the interpretation of quantum mechanics, \nis often based on different attitudes towards or even readings of Bohr. We propose that a better \nunderstanding of Bohr’s philosophical thought can contribute to the contemporary reconciliation of \nthese opposing philosophical views and thus to a better understanding of the quantum world. Unfortunately, \nin many contemporary interpretations, Bohr’s philosophical approach to quantum mechanics \nhas been misunderstood, re-interpreted or labelled as ambiguous. This is mostly due to the dispersion \nof Bohr’s complex and unique interpretation through different texts, never united in a single systematically \nconceptualized work. To comprehensively explain Bohr’s philosophical approach and his main \nphilosophical concepts, we consider the many similarities between Bohr’s and Husserl’s philosophical \napproach to science. Husserl developed his philosophical standpoint in a cultural context similar to \nBohr’s and shared Bohr’s objects of philosophical consideration as well as his approach to these objects. \nParallel reading of Bohr’s and Husserl’s texts reveals the closeness between Bohr’s ontological realism— \nepistemological anti-realism standpoint and Husserl’s phenomenological standpoint. This explains \ntheir similar views on the relationship between mathematical language, scientific method and Nature. \nWhile Bohr’s use of the term phenomenon is not equal to Husserl’s, Husserl’s rigorous philosophical \nexplanation of the term helps us to better understand Bohr’s use. Furthermore, the parallel reading \nfacilitates better understanding of one of Bohr’s main philosophical theses, often labelled as ambiguous \nand interpreted in different ways, that it is necessary to use classical concepts to describe quantum phenomena. \nWe claim that the thesis is connected with the advance of epistemological reconsideration of \nscience at the time of Bohr’s writing. Thus, Bohr considers some parts of argumentation as self-evident, \nwhile they are not evident to the contemporary reader. Husserl’s analysis of the relationship between science and the life-world offers a much-needed background for a comprehensive understanding of \nBohr’s thesis. The insight into the similarities between Bohr’s and Husserl’s philosophical approach \nto science and scientific phenomena enables a philosophically rigorous reading of Bohr’s texts; it can \neliminate some of the disagreements between realists and anti-realists and provide a firmer philosophical \nground for a dialog between them.
Niels Bohr, the founding father of modern atomic physics and quantum theory, was as original a philosopher as he was a physicist. This study explores several dimensions of Bohr's vision: the formulation of quantum theory and the problems associated with its interpretation, the notions of complementarity and correspondence, the debates with Einstein about objectivity and realism, and his sense of the infinite harmony of nature. The author's chief attention is given to Bohr's epistemological lesson, the conviction that all our description of nature is dependent on the words we use and the ways we can unambiguously use them. Against those who would view Bohr as a vague positivist, the author argues here that Bohr is best understood as using transcendental arguments and shaping a kind of descriptive metaphysics in his defence of our abilities to offer a description of the world we live in.
This thesis is an examination of the measurement problem from within the Copenhagen interpretation of quantum mechanics where I take issue with von Neumann’s theory of measurement which argues for the subjective collapse of the wave function by a conscious observer. I argue that von Neumann’s postulate of collapse has led to several intractable philosophical and conceptual problems in its account of quantum measurement. I argue that these problems arise from von Neumann’s misreading of Bohr’s complementarity regarding the relationship between subject and object as distinct metaphysical entities. Instead, I offer a new way of defining the subject-object relation based on Don Howard’s reading of Bohr’s complementarity as subject-object nonseparability (SON). I argue that the SON principle has the potential of placing Copenhagen on more solid philosophical footing by viewing the subject-object relationship not as a causal relation, but as a relation of ontological dependence to avoid the idea of collapse altogether.