Ioannis G. Ntagkas

We introduce a realist, unextravagant interpretation of quantum theory that builds on the existing physical structure of the theory and allows experiments to have definite outcomes but leaves the theory’s basic dynamical content essentially intact. Much as classical systems have specific states that evolve along definite trajectories through configuration spaces, the traditional formulation of quantum theory permits assuming that closed quantum systems have specific states that evolve unitarily along definite trajectories through Hilbert spaces, and our interpretation extends this intuitive picture of states and Hilbert-space trajectories to the more realistic case of open quantum systems despite the generic development of entanglement. We provide independent justification for the partial-trace operation for density matrices, reformulate wave-function collapse in terms of an underlying interpolating dynamics, derive the Born rule from deeper principles, resolve several open questions regarding ontological stability and dynamics, address a number of familiar no-go theorems, and argue that our interpretation is ultimately compatible with Lorentz invariance. Along the way, we also investigate a number of unexplored features of quantum theory, including an interesting geometrical structure—which we call subsystem space—that we believe merits further study. We conclude with a summary, a list of criteria for future work on quantum foundations, and further research directions. We include an appendix that briefly reviews the traditional Copenhagen interpretation and the measurement problem of quantum theory, as well as the instrumentalist approach and a collection of foundational theorems not otherwise discussed in the main text.

Wigner's quantum-mechanical classification of particle-types in terms of irreducible representations of the Poincaré group has a classical analogue, which we extend in this paper. We study the compactness properties of the resulting phase spaces at fixed energy, and show that in order for a classical massless particle to be physically sensible, its phase space must feature a classical-particle counterpart of electromagnetic gauge invariance. By examining the connection between massless and massive particles in the massless limit, we also derive a classical-particle version of the Higgs mechanism.

We address a long-standing debate over whether classical magnetic forces can do work, ultimately answering the question in the affirmative. In detail, we couple a classical particle with intrinsic spin and elementary dipole moments to the electromagnetic field, derive the appropriate generalization of the Lorentz force law, show that the particle's dipole moments must be collinear with its spin axis, and argue that the magnetic field does mechanical work on the particle's elementary magnetic dipole moment. As consistency checks, we calculate the overall system's energy-momentum and angular momentum, and show that their local conservation equations lead to the same force law and therefore the same conclusions about magnetic forces and work. We also compute the system's Belinfante-Rosenfeld energy-momentum tensor.

Abraham Robinson is well-known as the inventor of nonstandard analysis, which uses nonstandard models to give the notions of infinitesimal and infinitely large magnitudes a precise interpretation. Less discussed, although subtle and original–if ultimately flawed–is Robinson's work in the philosophy of mathematics. The foundational position he inherited from David Hilbert undermines not only the use of nonstandard analysis, but also Robinson's considerable corpus of pre-logic contributions to the field in such diverse areas as differential equations and aeronautics. This tension emerges from Robinson's disbelief in the existence of infinite totalities (any mention of them is ‘literally meaningless’) and the fact that much of his work involves them. I argue that he treats infinitary avenues of mathematics as useful tools to avoid this difficulty, but that this is not successful to the extent that these tools must be justified by a conservative extension from finitary mathematics. While Robinson provides a compelling and unorthodox pragmatic justification for the role of formal systems in mathematical practice despite their apparent infinitary presuppositions, he deflates mainstream mathematics to a collection of games that occasionally produces meaningful results. This amounts to giving up on a commitment to reconciling his finitism with his mathematical practice.

Several approaches to developing a theory of quantum gravity suggest that spacetime—as described by general relativity—is not fundamental. Instead, spacetime is supposed to be explained by reference to the relations between more fundamental entities, analogous to `atoms' of spacetime, which themselves are not (fully) spatiotemporal. Such a case may be understood as emergence of \textit{content}: a `hierarchical' case of emergence, where spacetime emerges at a `higher', or less-fundamental, level than its `lower-level' non-spatiotempral basis. But quantum gravity cosmology also presents us with the possibility of emergence of \textit{context}: where spacetime emerges from some `prior' non-spatiotemporal state (replacing the Big Bang), due to particular conditions in the early universe. I present a general conception of emergence which is plausibly able to accommodate both pictures. This is a positive conception that does not rely on a failure of reduction or explanation in any sense (indeed, reduction is a necessary feature of quantum gravity, and is useful in understanding emergence in this case). I also consider the possibility that the distinction between content- and context- based explanations is blurred, or usefully `collapsed', in the case of spacetime emergence.

Utilitarianism is the view according to which the only basic requirement of morality is to maximize net aggregate welfare. This position has implications for the ethics of creating and rearing children. Most discussions of these implications focus either on the ethics of procreation and in particular on how many and whom it is right to create, or on whether utilitarianism permits the kind of partiality that child rearing requires. Despite its importance to creating and raising children, there are, by contrast, few sustained discussions of the implications of utilitarian views of welfare for the matter of what makes a child’s life go well. This paper attempts to remedy this deficiency. It has four sections. Section one discusses the purpose of a theory of welfare and its adequacy conditions. Section two evaluates what prominent utilitarian theories of welfare imply about what makes a child’s life go well. Section three provides a sketch of a view about what is prudentially valuable for children. Section four sums things up

Likelihoodism is the view that the degree of evidential support should be analysed and measured in terms of likelihoods alone. The paper considers and responds to a popular criticism that a likelihoodist framework is too restrictive to guide belief. First, I show that the most detailed and rigorous version of this criticism, as put forward by Gandenberger (2016), is unsuccessful. Second, I provide a positive argument that a broadly likelihoodist framework can accommodate guidance for comparative belief, even when objectively well-grounded prior probabilities are not available. As I show, the shift from non-relational to comparative probabilities opens up a new space for addressing the belief guidance problem for likelihoodism.

Subjective Bayesianism is the current orthodoxy in confirmation theory. In broad outline, this view claims a) that confirmation is a relation of positive relevance, viz., that a piece of evidence confirms a theory if it increases its probability; b) that this relation of confirmation is captured by Bayes’s theorem; c) that, hence, the only factors relevant to confirmation of a theory are its prior probability, the likelihood of the evidence given the theory and the probability of the evidence; d) that the specification of the prior probability of a theory is a purely subjective matter; e) that the only constraint on an assignment of prior probabilities to several theories should be that they obey the axioms of the probability calculus; f) that, hence, the reasonableness of a belief does not depend on its content; nor, ultimately, on whether the belief is made reasonable by the evidence; and g) that degrees of belief are probabilities and that belief is always a matter of degree. This theory has had many successes. Old tangles, like the ravens paradox or the grue problem, are resolved. New tangles, like the problem of old evidence, have been, to some extent, resolved. But there is still a pervasive dissatisfaction with subjective Bayesianism. This dissatisfaction concerns all of the theses to above, but it is centred mostly around the point that subjective Bayesianism is too subjective to offer an adequate theory of confirmation and of rational belief. Yet, up until recently this dissatisfaction had not borne fruits in a fully developed alternative theory of confirmation. Perhaps, only Deborah Mayo’s error-statistical approach was a fully developed alternative, but this too faced considerable problems, one central among them being that she takes all probabilities to be relative frequencies. One thing is sure. Probability theory should place a central role in a theory of confirmation. But how are we to interpret probabilities if we want to avoid the subjective element of Bayesianism and the objective element of the error-statistical approach?

In recent years, there has been a growing interest in epistemic agency among philosophers. This development is in part owing to a growing interest in mental agency and epistemic normativity, along with associated concepts such as epistemic responsibility and the relationship between epistemic rationality and practical rationality. Most authors have focused solely on our agency exercised in the process of acquiring or forming beliefs in response to reasons. But some have examined temporally extended procedural epistemic agency, in particular our agency exercised in the process of inquiry. In this article, I argue for an account of procedural epistemic normativity grounded in a conception of the constitutive aim of inquiry. In doing so I will examine how an account of the constitutive aim of inquiry may both differ from and be like accounts of the constitutive aim of belief and the constitutive aim of intentional action. I propose that the constitutive aim of inquiry is understanding and that the aim of understanding may provide us with the norms of inquiry.

The development of artificial intelligence (AI) in medicine raises fundamental ethical issues. As one example, AI systems in the field of mental health successfully detect signs of mental disorders, such as depression, by using data from social media. These AI depression detectors (AIDDs) identify users who are at risk of depression prior to any contact with the healthcare system. The article focuses on the ethical implications of AIDDs regarding affected users’ health-related autonomy. Firstly, it presents the (ethical) discussion of AI in medicine and, specifically, in mental health. Secondly, two models of AIDDs using social media data and different usage scenarios are introduced. Thirdly, the concept of patient autonomy, according to Beauchamp and Childress, is critically discussed. Since this concept does not encompass the specific challenges linked with the digital context of AIDDs in social media sufficiently, the current analysis suggests, finally, an extended concept of health-related digital autonomy.

The mystery surrounding consciousness as subjectivity dissipates dramatically when understood in its biological context. The core characteristics of consciousness can be seen to derive from its functionality, and the fundamental function of cognition, given the equivalence of mental activity and brain process, is to advance the survival and thus the self-regulative capacity of the organism of which the brain is a part. These core elements of consciousness are comprised of a self-locational data structure which serves to configure ongoing experience in terms of controllable spatial and temporal parameters, and a processing regime for this orientational schema which has evolved from the feedback architecture necessary for regulating behavior in relation to homeostatic needs. These two self-regulative constituents yield a primitive form of consciousness as subjectivity — simple reflexive awareness — which provides the basis for the subsequent development of metacognitive mechanisms which monitor and control the cognitive processes which regulate behavior in relation to metabolic requirements

At the phenomenal level, consciousness can be described as a singular, unified field of recursive self-awareness, consistently coherent in a particualr way; that of a subject located both spatially and temporally in an egocentrically-extended domain, such that conscious self-awareness is explicitly characterized by I-ness, now-ness and here-ness. The psychological mechanism underwriting this spatiotemporal self-locatedness and its recursive processing style involves an evolutionary elaboration of the basic orientative reference frame which consistently structures ongoing spatiotemporal self-location computations as i-here-now. Cognition computes action-output in the midst of ongoing movement, and consequently requires a constant self-locating spatiotemporal reference frame as basis for these computations. Over time, constant evolutionary pressures for energy efficiency have encouraged both the proliferation of anticipative feedforward processing mechansims, and the elaboration, at the apex of the sensorimotor processing hierarchy, of self-activating, highly attenuated recursively-feedforward circuitry processing the basic orientational schema independent of external action output. As the primary reference frame of active waking cognition, this recursive i-here-now processing generates a zone of subjective self-awareness in terms of which it feels like something to be oneself here and now. This is consciousness.

Within the philosophy of mind, consciousness is currently understood as the expression of one or other cognitive modality, either intentionality , transparency , subjectivity or reflexivity . However, neither intentionality, subjectivity nor transparency adequately distinguishes conscious from nonconscious cognition. Consequently, the only genuine index or defining characteristic of consciousness is reflexivity, the capacity for autonoetic or self-referring, self-monitoring awareness. But the identification of reflexivity as the principal index of consciousness raises a major challenge in relation to the cognitive mechanism responsible for operationalizing such a reflexive state. Current reliance by higher-order and intrinsic self-representational theories on self-representing data structures to achieve reflexive self-awareness is highly problematic, suggesting a solution in terms of a self-referential processing regime.

In a recent paper in this journal, James Hawthorne, Jürgen Landes, Christian Wallmann, and Jon Williamson argue that the principal principle entails the principle of indifference. In this paper, I argue that it does not. Lewis’s version of the principal principle notoriously depends on a notion of admissibility, which Lewis uses to restrict its application. HLWW base their argument on certain intuitions concerning when one proposition is admissible for another: Conditions 1 and 2. There are two ways of reading their argument, depending on how you understand the status of these conditions. Reading 1: The correct account of admissibility is determined independently of these two principles, and yet these two principles follow from that correct account. Reading 2: The correct account of admissibility is determined in part by these two principles, so that the principles follow from that account but only because the correct account is constrained so that it must satisfy them. HLWWshow that, given an account of admissibility on which Conditions 1 and 2 hold, the principal principle entails the principle of indifference. I argue that, on either reading of the argument, it fails. First, I argue that there is a plausible account of admissibility on which Conditions 1 and 2 are false. That defeats reading 1. Next, I argue that the intuitions that lead us to assent to Condition 2 also lead us to assent to other very closely related principles that are inconsistent with Condition 2. This, I claim, casts doubt on the reliability of those intuitions, and thus removes our justification for Condition 2. This defeats the second reading of the HLWW argument. Thus, the argument fails.

This investigation is an attempt to spell out a formal semantic theory for inductive logic. The logic is probabilistic. It roughly resembles the logic of confirmation functions developed by Rudolf Carnap. ;Carnap's logic specifies an object language--the language of monadic predicate logic--and defines meta-linguistic probability functions on sentences of the object language. These probability functions express a semantic relationship between sentences, just as logical consequence is a semantic relationship between sentences in deductive logic. The semantic conditional probability functions express the degree of partial entailment or degree of confirmation that premises afford a conclusion. ;The system I develop is roughly of this kind, but on a stronger object language--one representing all of first-order logic and set-theory. It avoids the main problems with Carnap's approach, e.g., universally quantified sentences need not get probability 0 for infinite domains of objects. Also, unlike Carnap's system, the system developed here will not require that the logical structure of sentences be the sole determinant of all semantic probability relations. Only the semantic probabilities Carnap calls direct inferences--i.e., the conditional probability of the outcomes of instances, given a general statistical statement and the membership of the instances in an appropriate reference class--will depend on logical form alone. But in general the semantic probability of one sentence given another is not solely a matter of logical form. ;The system provides a rigorous formal account of the direct inferences as logical partial entailments. Logical entailments and logical partial entailments are to be the purely logical foundation on which a Bayesian logicist account of theory confirmation, or inverse inference, is constructed. The account is Bayesian in that the degree of confirmation of a hypothesis on evidence is related to direct inferences and to the prior plausibility of the hypothesis by way of Bayes' Theorem. The account is logicist in that conditional probabilities are developed as semantic relationships between sentences, and the semantics specifies certain purely logical relationships between sentences, the logical partial entailments

I argue for an epistemic conception of voting, a conception on which the purpose of the ballot is at least in some cases to identify which of several policy proposals will best promote the public good. To support this view I first briefly investigate several notions of the kind of public good that public policy should promote. Then I examine the probability logic of voting as embodied in two very robust versions of the Condorcet Jury Theorem and some related results. These theorems show that if the number of voters or legislators is sufficiently large and the average of their individual propensities to select the better of two policy proposals is a little above random chance, and if each person votes his or her own best judgment (rather than in alliance with a block or faction), then the majority is extremely likely to select the better alternative. Here ‘better alternative’ means that policy or law that will best promote the public good. I also explicate a Convincing Majorities Theorem, which shows the extent to which the majority vote should provide evidence that the better policy has been selected. Finally, I show how to extend all of these results to judgments among multiple alternatives through the kind of sequential balloting typical of the legislative amendment process.

"In this introduction I use Bertrand Russell's (1945) The History of Western Philosophy (hereafter: History), to introduce the meta-philosophical themes that recur throughout the chapters of this book. In particular, I focus on the way the distinction or opposition between rustic thought, which is supposed to characterize barbarous societies, and the urbane thought that is purported to characterize civilized society can help explain some entrenched patterns of exclusion visible in contemporary philosophy. I embed these remarks in a larger, speculative historiography of the very idea of 'western philosophy.' Along the way, I provide an overview of the chapters of this volume"--

In this introduction I use Bertrand Russell's (1945) The History of Western Philosophy (hereafter: History), to introduce the meta-philosophical themes that recur throughout the chapters of this book. In particular, I focus on the way the distinction or opposition between rustic thought, which is supposed to characterize barbarous societies, and the urbane thought that is purported to characterize civilized society can help explain some entrenched patterns of exclusion visible in contemporary philosophy. I embed these remarks in a larger, speculative historiography of the very idea of 'western philosophy.' Along the way, I provide an overview of the chapters of this volume.

Descartes's philosophy has had a considerable influence on the modern conception of the mind, but many think that this influence has been largely negative. The main project of The Subject's Point of View is to argue that discarding certain elements of the Cartesian conception would be much more difficult than critics seem to allow, since it is tied to our understanding of basic notions, including the criteria for what makes someone a person, or one of us. The crucial feature of the Cartesian view defended here is not dualism--which is not adopted--but internalism. Internalism is opposed to the widely accepted externalist thesis, which states that some mental features constitutively depend on certain features of our physical and social environment. In contrast, this book defends the minority internalist view, which holds that the mind is autonomous, and though it is obviously affected by the environment, this influence is merely contingent and does not delimit what is thinkable in principle. Defenders of the externalist view often present their theory as the most thoroughgoing criticism of the Cartesian conception of the mind; Katalin Farkas offers a defence of an uncompromising internalist Cartesian conception

In this paper Venn's account of probability inference and induction is examined, tracing their differences as well as how they ‘co-operate’ in inferences from particulars to particulars. We discuss the role of mathematical idealizations in making probability inferences, the celebrated rule of succession and we delve into the nature of the reference class problem arguing that for Venn it is a common problem for both induction and inference in probability. Our approach is both historical and philosophical attempting to sketch Venn's position both in the philosophy of probability and induction of his time and in relation to the twentieth-century frequentism.

Ontic Structural Realism (OSR) gives ontic priority to structures over objects. In its perhaps most extreme form (captured, admittedly, by a slogan) it states that “all that there is, is structure” (da Costa and French 2003, 189). If this is true, if there is nothing but structure(s) in the world, the very idea of contrasting structure to nonstructure loses any force it might have. Actually, if the slogan is right, the very idea of characterising what there is as structure—as opposed to anything else—becomes incoherent. Traditionally, characterising something as a structure has made full sense —and has served excellent scientific and philosophical purposes—precisely because structure was understood as an entity with slots, which could be occupied by objects and whose individuation-conditions involved objects only qua slot-fillers. If objects altogether go, whatever remains can be called ‘structure’ only if we take ‘structure’ to be a term of art. Well, Ontic Structuralists are happy to ‘mimic’ talk of non-structure, or objects in particular, but they hasten to add that this mimicking does not imply any serious metaphysical commitment to them. Here are a couple of characteristic passages.

This article defends the existence of _borderline consciousness._ In borderline consciousness, conscious experience is neither determinately present nor determinately absent, but rather somewhere between. The argument in brief is this. In considering what types of systems are conscious, we face a quadrilemma. Either nothing is conscious, or everything is conscious, or there’s a sharp boundary across the apparent continuum between conscious systems and nonconscious ones, or consciousness is a vague property admitting indeterminate cases. Assuming mainstream naturalism about consciousness, we ought to reject the first three options, which forces us to the fourth, indeterminacy. Standard objections to the existence of borderline consciousness turn on the inconceivability of borderline cases. However, borderline cases are only inconceivable by an inappropriately demanding standard of conceivability. I conclude with some plausible cases and applications.

Text-generative AI-systems have become important semantic agents with ChatGPT. We conducted a series of experiments to learn what teachers’ conceptions of text-generative AI are in relation to philosophical texts. In our main experiment, using mixed methods, we had twenty-four high school students write philosophical essays, which we then randomized to essays with the same command from ChatGPT. We had ten prospective teachers assess these essays. They were able to tell whether it was an AI or student essay with 78.7 percent accuracy, which is better than the Open AI Classifier. Interestingly, however, they used criteria like argumentative and logical flawlessness and neutrality. We concluded from this that they are using an inverted Turing test and are no longer looking for rationality in machines but for irrationality in humans.