Experiments involving delayed-choice entanglement swapping seem to suggest that particles can become entangled after they’ve already been detected. This astonishing result is taken by some to undermine realism about entanglement. In this paper, I argue that one can offer a fully realist explanation of delayed-choice entanglement swapping by countenancing timelike entanglement relations. I argue that such an explanation—radical though it may be—isn’t incoherent and doesn’t invite paradox. I compare this approach (...) to the antirealist alternative and a more deflationary realist strategy defended by Egg, each of which face certain challenges. The upshot is that we should take seriously the possibility of timelike entanglement and seek to develop a framework for quantum theory which allows for it. (shrink)

Delayed-choice experiments in quantum mechanics are often taken to undermine a realistic interpretation of the quantum state. More specifically, Healey has recently argued that the phenomenon of delayed-choice entanglement swapping is incompatible with the view that entanglement is a physical relation between quantum systems. This paper argues against these claims. It first reviews two paradigmatic delayed-choice experiments and analyzes their metaphysical implications. It then applies the results of this analysis to the (...) case of entanglement swapping, showing that such experiments pose no threat to realism about entanglement. (shrink)

Building on Peres’ idea of “Delayed-choice for entanglement swapping” we show that even the degree to which quantum systems were entangled can be defined after they have been registered and may even not exist any more. This does not arise as a paradox if the quantum state is viewed as just a representative of information. Moreover such a view gives a natural quantification of the complementarity between the measure of information about the input state for teleportation (...) and the amount of entanglement of the resulting swapped entangled state. (shrink)

Experiments demonstrating entanglement swapping have been alleged to challenge realism about entanglement. Seevinck claims that entangle- ment “cannot be considered ontologically robust” while Healey claims that entanglement swapping “undermines the idea that ascribing an entangled state to quantum systems is a way of representing some new, non-classical, physical relation between them.” My aim in this paper is to show that realism is not threatened by the possibility of entanglement swapping, but rather, it should (...) be informed by the phenomenon. I argue—expanding the argument of Timpson and Brown —that ordinary entanglement swapping cases present no new challenges for the realist. With respect to the delayed-choice variant discussed by Healey, I claim that there are two options available to the realist: deny these are cases of genuine swapping ) or allow for existence of entanglement between timelike separated regions. This latter option, while radical, is not incoherent and has been suggested in quite different contexts. While I stop short of claiming that the realist must take this option, doing so allows one to avoid certain costs associated with Egg’s “orthodox” account. I conclude by noting several important implication of entanglement swapping for how one thinks of entanglement generally. (shrink)

A quantum state represents neither properties of a physical system nor anyone’s knowledge of its properties. The important question is not what quantum states represent but how they are used—as informational bridges. Knowing about some physical situations, an agent may assign a quantum state to form expectations about other possible physical situations. Quantum states are objective: only expectations based on correct state assignments are generally reliable. If a quantum state represents anything, it is the objective probabilistic relations between its backing (...) conditions and its advice conditions. This paper offers an account of quantum states and their function as informational bridges, in quantum teleportation and elsewhere. (shrink)

Delayed-choice erasure is investigated in two-photon two-slit experiments that are generalizations of the micromaser experiment of Scully et al. (Nature 351:111–116, 1991). Applying quantum mechanics to the localization detector, it is shown that erasure with delayed choice in the sense of Scully, has an analogous structure as simple erasure. The description goes beyond probabilities. The EPR-type disentanglement, consisting in two mutually incompatible distant measurements, is used as a general framework in both parts of this study. Two (...) simple coherence cases are shown to emerge naturally, and they are precisely the two experiments of Scully et al. The treatment seems to require the relative-reality-of-unitarily-evolving-state (RRUES) approach. Besides insight in the experiments, this study has also the goal of insight in quantum mechanics. The question is if the latter can be more than just a “book-keeping device” for calculating probabilities as Scully et al. modestly and cautiously claim. (shrink)

It was pointed out in the first part of this study (Herbut in Found. Phys. 38:1046–1064, 2008) that EPR-type entanglement is defined by the possibility of performing any of two mutually incompatible distant, i.e., direct-interaction-free, measurements. They go together under the term ‘EPR-type disentanglement’. In this second part, quantum-mechanical insight is gained in the real random delayed-choice erasure experiment of Kim et al. (Phys. Rev. Lett. 84:1–5, 2000) by a relative-reality-of-unitarily-evolving-state (RRUES) approach (explained in the first part). (...) Finally, it is shown that this remarkable experiment, which performs, by random choice, two incompatible measurements at the same time, is actually an EPR-type disentanglement experiment, closely related to the micromaser experiment discussed in the first part. (shrink)

A 2015 experiment by Hanson and Delft colleagues provided further confirmation that the quantum world violates the Bell inequalities, being the first Bell test to close two known experimental loopholes simultaneously. The experiment was also taken to provide new evidence of ‘spooky action at a distance’. Here we argue for caution about the latter claim. The Delft experiment relies on entanglement swapping, and our main claim is that this geometry introduces an additional loophole in the argument from violation (...) of the Bell inequalities to action at a distance: the apparent action at a distance may be an artifact of ‘collider bias’. In the absence of retrocausality, the sensitivity of such experiments to this ‘Collider Loophole’ depends on the temporal relation between the entanglement swapping measurement C and the two measurements A and B between which we seek to infer a causal connection. CL looms large if the C is in the future of A and B, but not if C is in the past. The Delft experiment itself is the intermediate case, in which the separation is spacelike. We argue that this leaves it vulnerable to CL, unable to establish conclusively that it avoids it. (shrink)

We propose the Prototime Interpretation of quantum mechanics, which claims that quantum entanglement occurs in a "prototemporal" realm which underlies spacetime. Our paper is tentative and exploratory. The argument form is inference to the best explanation. We claim that the Prototime Interpretation (PI) is worthy of further consideration as a superior explanation for perplexing quantum phenomena such as delayed choice, superposition, the wave-particle duality and nonlocality. In Section One, we introduce the Prototime Interpretation. Section Two identifies its (...) advantages. Section Three discusses several implications of the view, such as its deterministic nature and relation to the simulation hypothesis. (shrink)

We describe a new class of experiments designed to probe the foundations of quantum mechanics. Using quantum controlling devices, we show how to attain a freedom in temporal ordering of the control and detection of various phenomena. We consider wave–particle duality in the context of quantum-controlled and the entanglement-assisted delayed-choice experiments. Then we discuss a quantum-controlled CHSH experiment and measurement of photon’s transversal position and momentum in a single set-up.

It is pointed out that a slight variation on the Wheeler Delayed Choice Experiment presents the same challenge to orthodox quantum mechanics as Maudlin-type contingent absorber experiments present to the Transactional Interpretation. Therefore, the latter cannot be used as a basis for refutation of TI.

In a recent paper (Zwirn in Phys Essays 30: 3, 2017), I argued against backward in time effects used by several authors to explain delayed choice experiments. I gave an explanation showing that there is no physical influence propagating from the present to the past and modifying the state of the system at a time previous to the measurement. However, though the solution is straightforward in the case of delayed choice experiments involving only one particle, it (...) is subtler in the case of experiments involving two entangled particles because they give rise to EPR-like situations. Considering that a measurement is not an actual change of the physical state of a system and is relative to the observer allows to understand that there is neither backward in time effects nor instantaneous collapse of the second system when the first one is measured, as is often postulated. This allows also to get rid of any non-locality (Zwirn in Found Phys 50:1–26, 2020). In this paper, I want to go further into the consequences of this way of considering the measurement, that I have called Convivial Solipsism, and show that even if, in the usual sense, there is no physical effect of the present or of the future on the past, we must nevertheless consider that the observer’s past is sometimes not entirely determined and that it becomes determined only when certain measurements are done latter. This apparent contradiction disappears if one understand that each observer builds, through her own measurements, her own world (that I call the phenomenal world in Convivial Solipsism) which is different from what we are used to consider as the common world shared by everybody. (shrink)

This paper explains the delayed choice quantum eraser of Kim et al. in terms of the transactional interpretation of quantum mechanics by Cramer. It is kept deliberately mathematically simple to help explain the transactional technique. The emphasis is on a clear understanding of how the instantaneous “collapse” of the wave function due to a measurement at a specific time and place may be reinterpreted as a relativistically well-defined collapse over the entire path of the photon and over the (...) entire transit time from slit to detector. This is made possible by the use of a retarded offer wave, which is thought to travel from the slits to the detector and an advanced counter wave traveling backward in time from the detector to the slits. The point here is to make clear how simple the transactional picture is and how much more intuitive the collapse of the wave function becomes if viewed in this way. Also, any confusion about possible retro-causal signaling is put to rest. A delayed choice quantum eraser does not require any sort of backward in time communication. This paper makes the point that it is preferable to use the TI over the usual Copenhagen interpretation for a more intuitive understanding of the quantum eraser delayed choice experiment. Both methods give exactly the same end results and can be used interchangeably. (shrink)

There is a fallacy that is often involved in the interpretation of quantum experiments involving a certain type of separation such as the: double-slit experiments, which-way interferometer experiments, polarization analyzer experiments, Stern-Gerlach experiments, and quantum eraser experiments. The fallacy leads not only to flawed textbook accounts of these experiments but to flawed inferences about retrocausality in the context of delayed choice versions of separation experiments.

The concept of retroactive apparent occurrence, the main ingredient of Wheeler's delayed-choice thought experiments, is systematically incorporated into the quantum theory of measurement (in the framework of the recent review of Busch, Lahti, and Mittelstaedt). Besides, the (general) notion of individual-system measurement is introduced, and, due to it, premeasurement is defined by a truly minimal condition. Finally, retroactive apparent occurrence is made use of to derive apparent objectification in measurement. The derivation is discussed in the framework of the (...) quantum mechanical approach to the objectification problem. (shrink)

It is demonstrated that ‘quantum eraser’ experiments do not erase any information. Nor do they demonstrate ‘temporal nonlocality’ in their ‘delayed choice’ form, beyond standard EPR correlations. It is shown that the erroneous erasure claims arise from assuming that the improper mixed state of the signal photon physically prefers either the ‘which way’ or ‘both ways’ basis, when no such preference is warranted. The latter point is illustrated through comparison of the QE spatial state space with the spin-1/2 (...) space of particles in the EPR-spin experiment. (shrink)

Recently, Bohr’s complementarity principle was assessed in setups involving delayed choices. These works argued in favor of a reformulation of the aforementioned principle so as to account for situations in which a quantum system would simultaneously behave as wave and particle. Here we defend a framework that, supported by well-known experimental results and consistent with the decoherence paradigm, allows us to interpret complementarity in terms of correlations between the system and an informer. Our proposal offers formal definition and operational (...) interpretation for the dual behavior in terms of both nonlocal resources and the couple work-information. Most importantly, our results provide a generalized information-based trade-off for the wave–particle duality and a causal interpretation for delayed-choice experiments. (shrink)

The prominent characteristic of a delayed-choice effect is to make the choice between complementary types of phenomena after the relevant interaction between the system and measuring instrument has already come to an end. In this paper, we first represent a detailed comparative analysis of some early delayed-choice propositions and also most of the experimentally performed delayed-choice proposals in a coherent and unified quantum mechanical formulation. Taking into the account the represented quantum mechanical descriptions (...) and also the rules of probability theory, we discuss that there are two fundamentally different descriptions concerning the physical mechanism of the delayed-choice between the complementary types of phenomena in these experiments. In this regard, we finally conclude that the delayed-choice experiments can be classified into two main groups where the temporal aspect of each group is characterized differently within their probabilistic descriptions. (shrink)

In this essay, I argue that genuine responsibility and ethical self-understanding are possible without narrative—or, at least, that narrative is not always sufficient. In §2, I introduce and clarify a distinction between our ontological subjectivity and everyday practical identity—one made famous by Heidegger and Sartre. On the basis of this distinction, in §3 I argue that narrative is unable to ground ethical choice and decision. For, although acting in light of practical identities is something we do, it cannot wholly (...) capture what it is to be who we are. Irrespective of whatever worldly projects and identities we press into, something about our subjectivity always remains unchanged. Narrative identity, which trades merely on practical identity, thus obscures this ontological dimension of life wherein human action, decision, choice, and responsibility truly originate. By way of conclusion, in §4, I briefly examine depictions of the narrative life found within the authorships of Dostoevsky, Kierkegaard, and Voltaire, illustrating how self-narrative at times invites self-deception and annuls responsibility. A life of genuine responsibility demands more than what the most candid and best intentioned of self-narratives can supply us. Living the good life, I shall intimate, is thus not something that involves mere narrative. It depends, rather, on inwardness. (shrink)

We treat here three apparently uncorrelated topics from the point of view of dense measurement: The EPR paradox, the teleportation process, and Wheeler's delayed-choice experiment (DCE). We begin with the DCE and show, using its unique nature and the histories formalism, that use may ascertain and fix the notion of dense measurement (the Zeno effect). We show here by including the experimenter (observer) as an inherent part of the physical system and using the Aharonov–Vardi notion of dense measurement (...) along a path, that knowledge of certain properties of the incoming system (after a measurement) is equivalent to dense measurement. We reach the same conclusion by discussing the teleportation process, and the EPR paradox from, the same point of view. (shrink)

In the present paper we expand upon ideas published some time ago in connection with which path detectors based on the micromaser. Frequently questions arise concerning the time ordering of detection and eraser events. We here show, by a detailed and careful analysis of a quantum eraser experimental setup, that the experimenter can choose to ascertain particle-like which path information or wavelike interference information even after the atom has hit the screen.

Options are often presented incidentally in a sequence, but does serial position impact choice after delay, and if so, how? We address this question in a consequential real-world choice domain. Using 25 years of citation data, and a unique identification strategy, we examine the relationship between article order and citation count. Results indicate that mere serial position affects the prominence that research achieves: Earlier-listed articles receive more citations. Furthermore, our identification strategy allows us to cast doubt on alternative (...) explanations and instead indicate that the effect is driven by psychological processes of attention and memory. These findings deepen the understanding of how presentation order impacts choice, suggest that subtle presentation factors can bias an important scientific metric, and shed light on how psychological processes shape collective outcomes. (shrink)

An essential feature of the quantum mechanical formalism, entanglement is widely thought to imply nonlocality or nonseparability as a puzzling trait of our ‘quantum world’. The notion of entanglement is reviewed and the question is addressed of whether invoking nonlocal influences, or perhaps time-reversed causation, is warranted in such ‘applications’ as quantum teleportation and entanglement swapping.

The paper deals with Forward exchange contracts and Swap exchange contracts, These two types of contracts are among the most prominent types of financial derivative contracts that arose after the collapse of the Bretton Woods system in 1971 or the so-called Nixon shock, where the convertibility of the dollar into gold was stoped, which led to turmoil in the exchange rates of the currencies of many countries and the emergence of the need to stabilize the exchange rate Currencies in transactions (...) where the delivery of the two exchanges is delayed. This research has studied forward exchange contracts and swap exchange contracts in four sections. The first section defines the Forward exchange contract, which is a contract in which the two parties commit to exchange a specified amount of foreign currencies on a forward date, at a price agreed upon in advance. The elements and elements that must be mentioned in this contract, such as the seller and buyer, the size of the contract, the date of delivery and the forward exchange rate, were mentioned in this section, with an illustrative example of the mechanism of conducting this contract. In addition to addressing the differences between forward exchange contracts and future exchange contracts, the characteristics of forward exchange contracts and the purposes of those dealing with them from hedging and speculation are mentioned in this section. The second section has been devoted to the definition of swap exchange contracts, it is for the two parties to the contract to agree that one of them buys from the other a specific amount of a currency in exchange for a specific amount of another currency and at the current exchange rate, provided that the two exchanges are delivered immediately, and in the same contract, the two parties agree to make a forward reverse exchange contract, at a price determined within Contract, and to clarify the picture of swap exchange contracts, an example has been given to illustrate the mechanism for conducting this type of contract. In the third section, the views of contemporaries scholars regarding the İslamic law of the forward exchange contract were discussed, where the opinion of the objectors was mentioned at all and the evidence they inferred from it. And then the opinion of those who advocate the permissibility of forward exchange contracts that are in the form of a dating that is not binding on both parties together, provided that there is nothing in the dating that indicates that it is a contract of sale and provided that a new contract is delivered independent of the dating. Then I discussed the opinion and evidence of the impediments in four points, and I concluded that the most correct opinion at the first is the impermissibility of the forward exchange contract in the form such as the traditional banks do it because of the deception it contains. But I recanted and permitted this type of contract in two cases, the first: the case of need with the absence of an alternative, and the second: the case that transaction is not binding dating for both parties and on some terms. Some contemporary scholars suggested conducting buying and selling operations in the same currency as an alternative to forward exchange contracts, and some of them suggested that Islamic banks should have a common unit of account to settle accounts between the parties to commercial transactions. But in my opinion two solutions are often not feasible. As for the fourth section, I dealt with the opinions of contemporary scholars in the swap exchange contract. it seems likely to me that swap currency exchange contracts are nothing but a usurious loan that is prohibited by Sharia. Because when examining the mechanism of conducting this type of contract, it turns out that one of the parties lent the other an amount in one currency in exchange for the other lending him an amount in another currency under the name of the spot exchange contract. Since one of the two parties requires the other to increase what he lent - if the exchange rate of the Forward exchange contract is different from the Spot exchange rate, which is predominant - under the name of the Forward exchange contract, then this process is nothing but a usurious loan. I supported the proposal to exchange loans in different currencies as a İslamic alternative to transaction contracts, provided that there is no preference for one party over another, and there is no usurious increase. And in order to solve the problem of the high rate of currency inflation of one of the two loans more than the other, the researcher suggested adding the inflation rate to the two loans when they are performed. (shrink)

Experimental studies suggest that individuals exhibit more risk aversion in choices among prospects when the payment and resolution of uncertainty are immediate relative to when it is delayed. This leads to preference reversals that cannot be attributed to discounting. When data suggest that utility is time-independent, probability weighting functions, such as those used to model prospect theory preferences, can accommodate such reversals. We propose a simple descriptive model with a two-parameter probability weighting function where one of these parameters depends (...) on the time at which a prospect is resolved. The time-dependent parameter is responsible for the curvature of the probability weighting function and is regarded as an index of sensitivity towards changes in probabilities. We provide conditions that characterize increased sensitivity towards more distant probabilities; this can account for the observed relatively less risk aversion towards delayed prospects. In our framework, the discount function is unrestricted, such that the model is compatible with empirical findings of non-constant discounting. In a simple application to bargaining we illustrate when it is advantageous for an individual to advance or delay the bargaining resolution time if an opponent displays increased sensitivity towards probability changes with delay. (shrink)

The concepts of choice, negation, and infinity are considered jointly. The link is the quantity of information interpreted as the quantity of choices measured in units of elementary choice: a bit is an elementary choice between two equally probable alternatives. “Negation” supposes a choice between it and confirmation. Thus quantity of information can be also interpreted as quantity of negations. The disjunctive choice between confirmation and negation as to infinity can be chosen or not in (...) turn: This corresponds to set-theory or intuitionist approach to the foundation of mathematics and to Peano or Heyting arithmetic. Quantum mechanics can be reformulated in terms of information introducing the concept and quantity of quantum information. A qubit can be equivalently interpreted as that generalization of “bit” where the choice is among an infinite set or series of alternatives. The complex Hilbert space can be represented as both series of qubits and value of quantum information. The complex Hilbert space is that generalization of Peano arithmetic where any natural number is substituted by a qubit. “Negation”, “choice”, and “infinity” can be inherently linked to each other both in the foundation of mathematics and quantum mechanics by the meditation of “information” and “quantum information”. (shrink)

Previous research has shown that subliminally presented stimuli accelerate or delay responses afforded by supraliminally presented stimuli. Our experiments extend these findings by showing that unconscious stimuli even affect free choices between responses. Thus, actions that are phenomenally experienced as freely chosen are influenced without the actor becoming aware of the manipulation. However, the unconscious influence is limited to a response bias, as participants chose the primed response only in up to 60% of the trials. LRP data in free (...) class='Hi'>choice trials indicate that the prime was not ineffective in trials in which participants chose the non-primed response as then it delayed performance of the incongruently primed response. (shrink)

This essay proposes to examine minority literature, and the scandals often associated with it, as a function of economy and choice. Rather than weighing the political strategies of identity and representation available to minority literature, this approach aims to dissect the ways its circulation is conditioned both by the modern liberal principle of self-ownership and by the flexible conversion of value among different economies characteristic of late capitalist forms of recognition. The entanglement of these spheres of value becomes (...) explicit in the moment of choice inherent to scandal, where the political or philosophical questions of minority identity are reduced to a matter of expenditure. Using the insights of Amartya Sen and Jean Baudrillard on the prerogative of choice in the constitution of capitalist subjects, I argue that it can offer a more comprehensive account of the political valence of minority literature, and its scandals, than the hermeneutics of representation. (shrink)

People often feel that a period of time becomes longer when it is described in more detail or cut into more segments, which is known as the time unpacking effect. The current study aims to unveil how time unpacking manipulation impacts intertemporal decision making and whether the gain-loss valence of choices moderates such impacts. We recruited 87 college students and randomly assigned them to the experimental conditions to complete a series of intertemporal choice tasks. The subjective values of the (...) delayed choices were calculated for each participant and then analyzed. The results showed that participants perceived longer time delays and higher subjective values on the delayed gains in the time unpacking conditions than in the time packing conditions. These results suggest that time unpacking manipulation not only impacts time perception but also other factors, which in turn, influence the valuation of delayed outcomes and thereby intertemporal choices. The results are discussed in comparison to previous studies to highlight the complexity of the mechanism underlying the effect of time unpacking on intertemporal decision making. (shrink)

Disorders of Consciousness (DoCs) raise difficult and complex questions about the value of life for persons with impaired consciousness, the rights of persons unable to make medical decisions, and our social, medical, and ethical obligations to patients whose personhood has frequently been challenged and neglected. Recent neuroscientific discoveries have led to enhanced understanding of the heterogeneity of these disorders, and focused renewed attention on the medical and ethical problem of misdiagnosis. -/- This book examines the entanglement of epistemic and (...) ethical uncertainty in DoCs and other medical contexts, and how they interact to create both epistemic and ethical risks. Philosopher and bioethicist L. Syd M Johnson pulls together multiple threads in this work: the ontological mysteries of consciousness, medical uncertainty about unconsciousness, ableist bias, withdrawal of treatment in neurointensive care, and the rarely questioned view that consciousness is essential to personhood and moral status. Johnson challenges longstanding bioethical dogmas about DoC patients, and argues for an ethics of uncertainty for contexts where there is a need for decisive action in the presence of unavoidable uncertainty. The ethics of uncertainty refocuses ethical inquiry concerning persons with DoCs, placing less emphasis on their contested personhood, and more on inductive risk and uncertainty, on respect for autonomy, and especially on epistemic justice. With applications to various decisional contexts where uncertainty and ethical risk interact, this ethical approach enables surrogate decision makers facing fraught and risky choices to fulfill their obligations as moral and epistemic agents. (shrink)

I use a theorem from machine learning, called the “No Free Lunch” theorem to support the claim that non-epistemic values are essential to theory choice. I argue that NFL entails that predictive accuracy is insufficient to favor a given theory over others, and that NFL challenges our ability to give a purely epistemic justification for using other traditional epistemic virtues in theory choice. In addition, I argue that the natural way to overcome NFL’s challenge is to use non-epistemic (...) values. If my argument holds, non-epistemic values are entangled in theory choice regardless of human limitations and regardless of the subject matter. Thereby, my argument overcomes objections to the main lines of argument revealing the role of values in theory choice. At the end of the paper, I argue that, contrary to common conception, the epistemic challenge arising from NFL is distinct from Hume’s problem of induction and other forms of underdetermination. (shrink)

Delay discounting is a common phenomenon in daily life, which refers to the subjective value of a future reward decreasing as a function of time. Previous studies have identified several cortical regions involved in delay discounting, but the neural network constructed by the cortical regions of delay discounting is less clear. In this study, we employed resting-state functional magnetic resonance imaging (RS-fMRI) to measure the spontaneous neural activity in a large sample of healthy young adults and used the Monetary (...) class='Hi'>Choice Questionnaire to directly measure participants’ level of delay discounting. To identify the neural network of delay discounting at rest, we used an individual difference approach to explore brain regions whose spontaneous activities were related to delay discounting across the whole brain. Then, these brain regions served as seeds to identify the neural network of delay discounting. We found that the fractional amplitude of low-frequency fluctuations (fALFF) of the left insula were positively correlated to delay discounting. More importantly, its connectivity to the anterior cingulate cortex was read out for participants’ behavioral performance in the task of delay discounting. In short, our study provides empirical evidence that insula-anterior cingulate cortex connectivity may serve as a part of the neural network for delay discounting. (shrink)

Schrödinger averred that entanglement is the characteristic trait of quantum mechanics. The first part of this paper is simultaneously an exploration of Schrödinger’s claim and an investigation into the distinction between mere entanglement and genuine quantum entanglement. The typical discussion of these matters in the philosophical literature neglects the structure of the algebra of observables, implicitly assuming a tensor product structure of the simple Type I factor algebras used in ordinary Quantum Mechanics . This limitation is overcome (...) by adopting the algebraic approach to quantum physics, which allows a uniform treatment of ordinary QM, relativistic quantum field theory, and quantum statistical mechanics. The algebraic apparatus helps to distinguish several different criteria of quantum entanglement and to prove results about the relation of quantum entanglement to two additional ways of characterizing the classical versus quantum divide, viz. abelian versus non-abelian algebras of observables, and the ability versus inability to interrogate the system without disturbing it. Schrödinger’s claim is reassessed in the light of this discussion. The second part of the paper deals with the relativity-to-ambiguity threat: the entanglement of a state on a system algebra is entanglement of the state relative to a decomposition of the system algebra into subsystem algebras; a state may be entangled with respect to one decomposition but not another; hence, unless there is some principled way to choose a decomposition, entanglement is a radically ambiguous notion. The problem is illustrated in terms a Realist versus Pragmatist debate, the former claiming that the decomposition must correspond to real as opposed to virtual subsystems, while the latter claims that the real versus virtual distinction is bogus and that practical considerations can steer the choice of decomposition. This debate is applied to the fraught problem of measuring entanglement for indistinguishable particles. The paper ends with some remarks about claims in the philosophical literature that entanglement undermines the separability or independence of subsystems while promoting holism. (shrink)

Biotechnological advance is speeding the development of drugs. The approval processes for new drugs will inevitably involve a regulatory agency in making political-economic and scientific choices. Interests of specific patients and the public in general are to be considered, and enormous stakes are involved for companies concerned. A medical regulatory authority must be at once insulated from and responsive to many different mixes of singular and general interests and pressures. Access to new drugs can be spurred by the press of (...) patient advocacy groups, but if there are well organized groups to monitor the testing and approval process for such as AIDS or cancer drugs there is often no similar group to represent patient needs. If there is no organized patient advocacy group, compassionate responsibility by a medical regulatory authority is indeed called for. Delay in the approval of new drugs for fighting severe blood infections raises the question of how to insure the compassionate responsibility of a regulatory authority. (shrink)

South Africa has an abortion law which codifies the broad themes of reproductive rights set out in the Constitution of South Africa, other laws and national guidelines. Certain wording of the conditions in the Choice Act for abortion after 20 weeks' gestation, are open to interpretation, being ‘severe malformation of the fetus’ and ‘risk of injury to the fetus’. From 24 weeks onwards, abortion is carried out by feticide/induced fetal cardiac asystole (‘IFCA’) and subsequent induction of labour in South (...) Africa. Some maternal‐fetal units have developed guidelines to assist clinicians and patients in decision‐making around eligibility for abortion after 20 weeks' gestation, given the broad terms in the law. We consider the guideline used by an institution in the Western Cape for abortion after 23 weeks and 6 days gestation, in terms of its alignment with the law on reproductive rights and its compliance with fair and transparent procedures. We also note its effect on respect for patients and on staff professionalism. (shrink)

We propose partial measurements as a conceptual tool to understand how to operate with counterfactual claims in quantum physics. Indeed, unlike standard von Neumann measurements, partial measurements can be reversed probabilistically. We first analyze the consequences of this rather unusual feature for the principle of superposition, for the complementarity principle, and for the issue of hidden variables. Then we move on to exploring non-local contexts, by reformulating the EPR paradox, the quantum teleportation experiment, and the entanglement-swapping protocol for (...) the situation in which one uses partial measurements followed by their stochastic reversal. This leads to a number of counter-intuitive results, which are shown to be resolved if we give up the idea of attributing reality to the wavefunction of a single quantum system. (shrink)