Although Bohr's reply to the EPR argument is supposed to be a watershed moment in the development of his philosophy of quantum theory, it is difficult to find a clear statement of the reply's philosophical point. Moreover, some have claimed that the point is simply that Bohr is a radical positivist. In this paper, we show that such claims are unfounded. In particular, we give a mathematically rigorous reconstruction of Bohr's reply to the _original_ EPR argument that (...) clarifies its logical structure, and which shows that it does not rest on questionable philosophical assumptions. Rather, Bohr's reply is dictated by his commitment to provide "classical" and "objective" descriptions of experimental phenomena. (shrink)

Halvorson and Clifton have given a mathematical reconstruction of Bohr’s reply to Einstein, Podolsky and Rosen (EPR), and argued that this reply is dictated by the two requirements of classicality and objectivity for the description of experimental data, by proving consistency between their objectivity requirement and a contextualized version of the EPR reality criterion which had been introduced by Howard in his earlier analysis of Bohr’s reply. In the present paper, we generalize the above consistency (...) theorem, with a rather elementary proof, to a general formulation of EPR states applicable to both non-relativistic quantum mechanics and algebraic quantum field theory; and we clarify the elements of reality in EPR states in terms of Bohr’s requirements of classicality and objectivity, in a general formulation of algebraic quantum theory. (shrink)

Bohr’s reply to Einstein, Podolsky, and Rosen’s argument for the incompleteness of quantum theory is notoriously difficult to unravel. It is so diffcult, in fact, that over 60 years later, there remains important work to be done understanding it. Work by Fine , Beller and Fine , and Beller goes a long way towards correcting earlier misunderstandings of Bohr’s reply. This essay is intended as a contribution to the program of getting to the truth of the (...) matter, both historically and philosophically. In a paper of this length, a full account of Bohr’s reply is impossible, and so I shall focus on one issue where it seems further clarification is required, namely, Bohr’s attempt to illustrate EPR’s argument by means of a thought experiment. In addition, I shall attempt to clarify a few other points which, however minor, have apparently contributed to misunderstandings of Bohr’s position. As the title of this paper suggests, an account of these few points does not constitute an account of Bohr’s reply, but it is an important step in that direction. (shrink)

Ever since the beginning of development of Quantum Mechanics there was a metaphysical division between the “macro” world as described in “everyday language” and the “micro” world described by quantum formalism. A discussion is offered of the need to reunite these arbitrarily divided worlds through an overview of the main interpretations of the formalism. Bohr’s Copenhagen interpretation, as well as the problems it faces due to EPR thought experiment, is presented in greater detail. It is claimed that Bohr’s (...) answers to the said experiment demand more than a restriction of everyday descriptive metaphysics, when describing phenomena at the micro-level. Thus, the special place Bohr’s interpretation takes among other interpretations of the formalism is forfeited. It is also shown that MacKinnon’s more detailed schema aiming to connect the theoretical and everyday language cannot be applied to EPR conclusions and Bohr’s reply to those. MacKinnon’s own modifications of the “everyday language” induced by the mathematical conclusions of Quantum Mechanics are considered too radical and too coarse to take the vacated special place among formalism interpretations. (shrink)

The Heisenberg microscope and its analysis by Weizsäcker are used by Grete Hermann in her 1935 essay on the foundations of quantum mechanics to argue her claims about causality in quantum mechanics. In this chapter, I wish to draw a comparison between Hermann’s use of the Heisenberg microscope and another famous use of a very similar thought experiment : Bohr’s analysis of the suspended single slit in his reply to EPR. I shall argue that Hermann’s use of different (...) aspects of the classical pictures in the treatment of the Heisenberg microscope makes her treatment closer to Bohr’s discussion of the suspended slit than to Heisenberg’s own treatment of the microscope. This suggests that Hermann, who equally gave an extensive analysis of complementarity in her 1935 essay, may be an especially acute interpreter of Bohr’s views. I conclude by looking at Hermann’s approach in the context of more general examples of measurement and at possible limitations of the approach. (shrink)

In my reconstruction of Bohr's reply to the Einstein-Podolsky-Rosen argument, I pointed out that Bohr showed explicitly, within the framework of the complementarity interpretation, how a locally maximal measurement on a subsystem S2 of a composite system S1+S2, consisting of two spatially separated subsystems, can make determinate both a locally maximal Boolean subalgebra for S2 and a locally maximal Boolean subalgebra for S1. As it stands, this response is open to an objection. In this note, I show that meeting (...) the objection requires a modification of the complementarity thesis concerning what propositions can be taken as determinate, or what observables can be raken to have values, in a given measurement context. (shrink)

The present article reports on the finding of the principle behind quantum mechanics. The principle, referred to as genuine fortuitousness, implies that the basic event, a click in a counter, comes without any cause and thus as a discontinuity in spacetime. From this principle, the formalism of quantum mechanics emerges with a radically new content, no longer dealing with things to be measured. Instead, quantum mechanics is recognized as the theory of distributions of uncaused clicks that form patterns laid down (...) by spacetime symmetry and is thereby revealed as a subject of unexpected simplicity and beauty. The departure from usual quantum mechanics is strikingly borne out by the absence of Planck's constant from the theory. The elimination of indeterminate particles as cause for the clicks, which the principle of genuine fortuitousness implies, is analogous to the elimination of the ether implied by the principle of relativity. (shrink)

Translation: Niels BOHR, "Light and Life." Nature, roč. 131, 1933, s. 421–423 (první část), s. 457–459 (druhá část).

This essay shows the difficulties inherent in the very term of ›culture‹ itself, spe- cifically in political and philosophical contexts between 1910 and 1933. Despite the eagerness and the striking idealism of its founders, Logos never offered an under- standing of culture that was able to resist the totalitarian tendencies of its own time. The term ›culture‹ thus continues to contaminate every attempt to formulate the legacy of the Logos project. From today’s perspective, that means recognizing the need to come (...) to terms with the connotations and the implications of such a project as Logos rather than rushing into a naive and simplistic affirmation. Al- though not the first, Klaus Christian Köhnke and Rüdiger Kramme were the most insistent researchers who brought up this painful subject of the modern history of philosophy. (shrink)

This study posits that Bohr failed to defend the completeness of the quantum mechanical description of physical reality against Einstein–Podolsky–Rosen’s paper. Although there are many papers in the literature that focus on Bohr’s argument in his reply to the EPR paper, the purpose of the current paper is not to clarify Bohr’s argument. Instead, I contend that regardless of which interpretation of Bohr’s argument is correct, his defense of the quantum mechanical description of physical reality remained (...) incomplete. For example, a recent trend in studies of Bohr’s work is to suggest he considered the wave-function description to be epistemic. However, such an interpretation cannot be used to defend the completeness of the quantum mechanical description. (shrink)

In 1935, Einstein, Podolsky and Rosen famously published a paper arguing for the incompleteness of quantum mechanics, using the example of two spatially separated but entangled particles. In his almost equally famous reply, Niels Bohr argued against EPR by providing a careful analysis of quantum measurements from the point of view of complementarity. Perhaps oddly, this analysis focuses on the example of a *single* particle passing through a slit. In this paper I argue that the disanalogy between the two (...) examples is only apparent, and does not constitute an obstacle in trying to understand Bohr's views on complementarity. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:CONRAD'S REPLY TO KIERKEGAARD by Jerry S. Clegg Varied answers to a fixed question have often guided interpretations of Conrad's novella, Heart ofDarkness. Who, that question has been, was Conrad's model for the enigmatic colonial official he calls Kurtz? Hannah Arendt has speculated that it was Carl Peters, an early explorer of east Africa.1 Norman Sherry has picked Arthur Hodister, a Belgian officer, as his candidate.2 Ian Watt (...) has likewise suggested historical figures: Henry M. Stanley and King Leopold of Belgium.3 Since all these men had a reputation for cruelty, those thinking that Conrad had them in mind when describing Kurtz have stressed the political message of his story; for them it is basically an indictment of colonialism. Stephen Reid has argued for a mythic model. Kurtz, he holds, was meant to be seen as one of the man-gods of Frazer's Golden Bough—a primitive king who is obliged to maintain his political position by engaging in certain bestial rites.4 Kenneth Bruffee has recendy cast Kurtz as Conrad's version of Byron's Childe Harold, arguing that the eventualjudgment on him by the character Marlow represents the effort of a squire-narrator to free himself from the pernicious influence of his knight-hero.5 For Bruffee Heart of Darkness is the prototype of a genre oftwentieth-century literature thatrejects the values ofaristocratic romance in favor of democratic norms. There may be truth in all these associations of Kurtz with known colonizers, mythical kings, and fictional knights, but they share a pair of deficiencies. They do not clarify the argument of Heart ofDarkness and so do not dojustice to its copious philosophical content. They also 280 Jerrys. Clegg281 fail to note those features ofKurtz that identify his model most precisely. The prototype of Conrad's famous character is biblical. He is a modern version of Abraham, and the work most intimately related to Heart of Darkness is Kierkegaard's panegyric on Abraham: Fear and Trembling. Conrad's story is, in fact, an addendum to Fear and Trembling written from the point of view of a poet-narrator—Marlow—who has accepted some, but not all, of the tenets of Kierkegaard's own poet-narrator, Johannes de Silentio. It is Marlow's quarrel with de Silentio that explains the structure of Heart ofDarkness, that constitutes its deepest message, and that tells the reader who the model for Kurtz was. An appreciation of that quarrel also helps clarify other matters. It makes plain, for example, the symbolism of light and dark that Conrad uses as an accompaniment to his argument.6 Heart of Darkness is, unarguably, a meditation on several subjects. It is about the Belgian Congo under the administration of King Leopold. It is also about European colonialism in general. It may be about other matters as well. Its primary subject, however, is the relationship of the religious to the ethical and the aesthetic. Since for Conrad the ethical and the aesthetic were allied, this subject may be best cast as the relationship ofreligion to art. It is introduced at the very start ofthe novella. Conrad's primary narrator there offers a theme for his seafaring friend, Marlow, to meditate on aloud: the great English knights-errant of the sea who, like "jewels flashing in the night of time," have born the torch of civilization into the mystery of an unknown earth.7 As this theme is announced, what was a mournful gloom that had hung over London becomes a lurid glare under the stars, and Marlow begins to talk of these, and still other, kinds of light and their relationship to the dark. The primary narrator has already identified what the dark stands for: time. Marlow does not challenge that equation. He only asks who, and with the aid of what kind of light, effectively combats "the night of time." During his meditation he considers four answers to his question, three of which are of primary importance. Certain "redeeming facts," illustrated by the restraint shown by hungry cannibals, quietly dazzle with reassurance, and so what mightbe called the person ofethical conduct— when stripped bare of pretense and the opaque "cloak of time... (shrink)

Soviet attitude towards Bohr reflects changes in the ideological approach to science. During the last period before Stalin's death danov proclaimed the campaign against Western influence in Soviet philosophy and science. Nevertheless the physicist M. A. Markov tried to introduce complementarity as a materialistic interpretation of quantum-mechanics in 1948. He was officially condemned. This was followed by a period (1948-54) during which heavy attacks were made against the Copenhagen school. In 1958, after a personal exchange of thoughts with Bohr, academician (...) Fock declared complementarity and probability to be irreversible steps towards a new insight into physical reality, at the same time correcting some of Bohr's epistemological conceptions. (shrink)

In a paper published in this Journal, Hans Radder argues that a detailed analysis of the degenerating phase of Bohr's programme reveals the basic incorrectness of Lakatos' own reconstruction of this period. Furthermore the corrected version shows the impossibility to account for the development in Lakatosian concepts. In this reply I try to point out that a slight modification of Lakatos' reconstruction is sufficient for reconciling the theory with the historical data. It is not Lakatos's theory itself that causes (...) the problems, but Radder's way of its application. (shrink)

Linsky’s central point is correct; Kripke’s distinction between rigid and nonrigid designators can be extended in a straightforward way from singular terms to general terms. In both cases, for an expression to rigidly designate its extension is for it to designate the same extension with respect to every possible world-state (in which it has an extension at all). On this account, simple natural kind terms like water, gold, electricity, blue, and tiger – as well as ordinary general terms like bachelor, (...) philosopher, automobile and triangle – designate the same extension with respect to each world-state. As I see it, however, the two differ importantly in the metaphysics of their designata. Whereas a term like bachelor designates a property that may be distinguished from other properties that are necessarily coextensive with it, natural kinds differ from one another only if there are possible world-states in which some of their instances are different. Intuitively this seems plausible; it is hard to imagine two distinct species of animal, two distinct substances, or two distinct colors which have precisely the same instances in every possible world-state. This is important for my linguistic model. Consider, for example, the color blue (which I take to be a natural kind). Color science tells us that the object-color blue is determined.. (shrink)

Abstractabstract:In a recent issue of the Journal of the History of Philosophy, Matt Bower argues forcefully against A. D. Smith's interpretation of Husserl as a disjunctivist. But I argue in this discussion note that the disjunctive reading of Husserl remains plausible. For it seems Husserl was committed to the idea that perceptions essentially have singular contents, while hallucinations do not.

Brian Garrett (Analysis (2012), 293–5) comments on McCall's paper (Analysis (2011), 501–6). McCall had claimed that since the truth of true empirical propositions supervenes on, and depends upon, empirical fact, what God knows and does not know also depends upon being, i.e. upon facts. Consequently God's foreknowing what I freely decide to do depends upon what I freely do. Garrett objects that the dependence of truth on being seems to play no essential role in McCall's argument. McCall replies that his (...) argument is an up-to-date version of Luis de Molina's 16th century reconciliation of freewill with omniscience, in which the dependence of God's knowledge on what humans do is crucial. (shrink)

Some form of utilitarian approach can be discerned as underlying much current medical ethical decision-making. Criticisms of the practical effects of such an approach are not parried by asserting the fundamental strengths of utilitarianism as theory.

We report on the simultaneous determination of complementary wave and particle aspects of light in a double-slit type “welcher-weg” experiment beyond the limitations set by Bohr’s Principle of Complementarity. Applying classical logic, we verify the presence of sharp interference in the single photon regime, while reliably maintaining the information about the particular pinhole through which each individual photon had passed. This experiment poses interesting questions on the validity of Complementarity in cases where measurements techniques that avoid Heisenberg’s uncertainty principle (...) and quantum entanglement are employed. We further argue that the application of classical concepts of waves and particles as embodied in Complementarity leads to a logical inconsistency in the interpretation of this experiment. (shrink)

In my response, I initially defend my preference for classical Critical Theory, emphasizing its continued relevance in capitalist modernity, stressing that the epistemological approach does not imply dogmatism with regards to scientific theory or Historical Materialism, just as it does not imply closure with regards to political democracy. When it comes to the dialectics of the classics, I also defend an epistemological approach, arguing that the dialectics aiming for truth implies critique and negativity. However, confronted with the duality of transcendental (...) ideas and historical relativity, I express my confidence in human intuition. Following Hegel, determinate negation must sublate the intuitively conceived universality to a new conception that contains the result of the negation. Finally, I do not see how the conceptual aporias of general economy can be solved by the current political degrowth project. Still, politics is what we need more of, namely social democracy. (shrink)

Libertarians oppose coercion and champion a free-market society. Are these two commitments, as libertarians claim, wholly consistent with one another, or is there, by contrast, a tension between them? This paper defends the latter view. Replying to an article by Gordon Barnes, the paper casts doubts on the success of an argument aimed at establishing that, while coercion is justice-disrupting, all non-coercive but forced transactions that occur in a free market are justice-preserving.