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64117.728572
The aim of this paper is to examine the extent to which the ‘privileged coordinates’ of a physical theory provide a window into how much structure it posits. We first isolate a problem for this idea. We show that there are geometric spaces that admit the same privileged coordinates, but have different amounts of structure. We then compare this ‘coordinate approach’ to comparing amounts of structure to the familiar ‘automorphism approach,’ and we conclude with some brief remarks about implicit definability.
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98550.728798
This is the summer break and I’m publishing old essays written when the audience of this newsletter was confidential. This post has been originally published April 5, 2022. In a previous post, I briefly mentioned the suggestion made by the philosopher Paul Weithman about a possible Rawlsian account of the populist vote. …
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164630.728824
Has the “abandon significance” movement in statistics trickled down into philosophy of science? A little bit. Nowadays (since the late 1990’s [i]), probabilistic inference and confirmation enter in philosophy by way of fields dubbed formal epistemology and Bayesian epistemology. …
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238382.728837
It has been recently debated whether world branching in the many-worlds interpretation of quantum mechanics (MWI) is global or local. In this paper, I present a new analysis of the branching process in MWI. First, I argue that branching is not global. Next, I argue that branching is not necessarily local either, and it can be nonlocal for particles being in an entangled state. Third, I argue that for nonlocal branching there is action at a distance in each branching world, and as a result, there is also a preferred Lorentz frame in the world. However, the action at a distance in each world is apparent in the sense that there is no action at a distance and resulting preferred Lorentz frame in the whole worlds, and thus MWI is consistent with special relativity.
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431920.728849
According to subject-sensitive invariantism (SSI), whether S knows that p depends not only on the subject’s epistemic position (the presence of a true belief, sufficient warrant, etc.) but also on non-epistemic factors present in the subject’s situation; such factors are seen as “encroaching” on the subject’s epistemic standing. Not the only such non-epistemic factor but the most prominent one consists in the subject’s practical stakes. Stakes-based SSI holds that two subjects can be in the same epistemic position with respect to some proposition but with different stakes for the two subjects so that one of them might know the proposition while the other might fail to know it. It is remarkable that the notion of stakes has not been discussed much in great detail at all so far. This paper takes a closer look at this notion and proposes a detailed, new analysis. It turns out that there is more than one kind of stakes, namely event-stakes, knowledge-stakes and action-stakes. I discuss several issues that even plausible notions of stakes raise and propose solutions.
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470612.728871
A principal would like to decide which of two parties deserves a prize. Each party privately observes the state of nature that determines which of them deserves the prize. The principal presents each party with a text that truthfully describes the conditions for deserving the prize and asks each of them what the state of nature is. The parties can cheat but the principal knows their cheating procedure. The principal “magically implements” his goal if he can come up with a pair of texts satisfying that in any dispute, he will recognize the cheater by applying the “honest-cheater asymmetry principle”. According to this principle, the truth is with the party satisfying that if his statement is true, then the other party (using the given cheating procedure) could have cheated and made the statement he is making, but not the other way around. Examples are presented to illustrate the concept.
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470635.728879
A “problem solver” (PS) is an agent who when interacting with other agents does not “put himself in their shoes” but rather chooses a best response to a uniform distribution over all possible configurations consistent with the information he receives about the other agents’ moves.
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585089.728885
Mainstream statistical physics proceeds by assigning probability functions to classical systems, and mixed quantum states to quantum systems, and then calculating synchronic and diachronic properties of those functions. Recent philosophy of physics refers to this mainstream approach as “Gibbsian statistical mechanics” (henceforth GSM) and contrasts it, usually unfavorably, to (so-called) “Boltzmannian statistical mechanics”, in which the role of probability is lessened and in some versions eliminated altogether.
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585114.728891
One type of computational indeterminacy arises from partitioning a system’s physical state space into state types that correspond to the abstract state types underlying the computation concerned. The mechanistic individuative strategy posits that computation can be uniquely identified through either narrow physical properties exclusively or wide, proximal properties. The semantic strategy posits that computation should be uniquely identified through semantic properties. We develop, and defend, an alternative functional individuative strategy that appeals—when needed—to wide, distal functions. We claim that there is no actual computation outside of a functional context. Desiderata for the underlying notion of teleofunction are discussed.
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620750.728899
TLDR: You’re unsure about something. Then it happens—and you think to yourself, “I kinda expected that.” Such hindsight bias is commonly derided as irrational. But any Bayesian who is (1) unsure of exactly what they think, and (2) trusts their own judgment should exhibit hindsight bias. …
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699575.728905
It is well known how to define the operator Q for the total charge (i.e., positron number minus electron number) on the standard Hilbert space of the second-quantized Dirac equation. Here we ask about operators QA representing the charge content of a region A ⊆ R in 3d physical space. There is a natural formula for QA but, as we explain, there are difficulties about turning it into a mathematically precise definition. First, QA can be written as a series but its convergence seems hopeless. Second, we show for some choices of A that if QA could be defined then its domain could not contain either the vacuum vector or any vector obtained from the vacuum by applying a polynomial in creation and annihilation operators. Both observations speak against the existence of QA for generic A.
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711238.728912
Standard approaches to ontological simplicity focus either on the number of things or types a theory posits or on the number of fundamental things or types a theory posits. In this paper, I suggest a ground-theoretic approach that focuses on the number of something else. After getting clear on what this approach amounts to, I motivate it, defend it, and complete it.
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761219.728918
It is an honor to have been asked to contribute a paper to a Festschrift for John Martin Fischer and it is a pleasure to do so. A paper to be included in a volume honoring a scholar need not, speaking strictly, address that scholar’s work, but I would not dream of contributing an essay to a book honoring John that was not about his work. That resolution, however, confronts me with a problem, for the only things worth anyone’s attention that I have to say about John’s contributions to philosophy pertain to his well-known and influential work on the relation (or lack thereof) between determinism and moral responsibility, and those things I have already said —and said as well as I shall ever be able to. The only solution to this problem seems to me to be to reply to one of John’s criticisms of my own work—which carries the danger of my own work, rather than John’s, becoming the topic of this chapter. My only excuse for risking this unseemly outcome is that when I tried to think of a topic for the essay that addressed John’s work and about which I had something to say that I had not already said, only this came to mind.
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798876.728924
When do two sentences say the same thing, that is, express the same content? We defend two-component (2C) semantics: the view that propositional contents comprise (at least) two irreducibly distinct constituents: (1) truth-conditions and (2) subject-matter. We contrast 2C with one-component (1C) semantics, focusing on the view that subject-matter is reducible to truth-conditions. We identify exponents of this view and argue in favor of 2C. An appendix proposes a general formal template for propositional 2C semantics.
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877620.72893
Copyright: © 2024 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).
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931182.728954
Hardy’s ψ-ontology theorem proves the reality of the wave function under the assumption of restricted ontic indifference. It has been conjectured that restricted ontic indifference, which is a very strong assumption from the ψ-epistemic view, can be derived from two weaker sub-assumptions: an ontic state assumption and a locality assumption. However, Leifer argued that this derivation cannot go through when considering the existence of the vacuum state in the second-quantized description of quantum states. In this paper, I present a new analysis of Hardy’s theorem. First, I argue that the ontic state assumption is valid in the second-quantized description of quantum states. Second, I argue that the locality assumption is a locality assumption for product states and it is weaker than the preparation independence assumption of the PBR theorem. Third, I argue that Leifer’s objection to the derivation of restricted ontic indifference is invalid. Finally, I argue that although the vacuum state is irrelevant, the existence of the tails of the wave function will block the derivation of restricted ontic indifference from the ontic state assumption and the locality assumption.
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931202.72896
This paper designs and defends a conceptual framework for the disambiguation of scientific language regarding open and closed systems. We argue that the open-closed distinction should always be precisifed by specifying a characteristic quantity that is conserved if and only if the system is closed. Open systems are those for which conservation of the characteristic quantity fails. This precisification is in accord with much but not all existing practice. We show that an open system can have well-posed autonomous dynamics and need not be embeddable in any larger system. We distinguish two kinds of autonomy and show that they dissociate from the open-closed distinction. We argue that this framework clears the path towards a new approach to the modelling of autonomous open systems in quantum physics and cosmology.
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931220.728966
In a recent paper (Found Phys 54:14, 2024), Carcassi, Oldofredi and Aidala concluded that the ψ-ontic models defined by Harrigan and Spekkens cannot be consistent with quantum mechanics, since the information entropy of a mixture of non-orthogonal states are different in these two theories according to their information theoretic analysis. In this paper, I argue that this no-go theorem for ψ-ontic models is false by explaining the physical origin of the von Neumann entropy in quantum mechanics.
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1227219.728972
Preliminary note: This essay is the last one before my summer break. The newsletter will not stop completely, though. See at the end of the post for more information. A couple of weeks ago, Eric Schliesser published an essay on Gerald Gaus’s criticism of Isaiah Berlin’s account of value pluralism. …
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1263092.728979
How to compute the probability distribution of a detection time, i.e., of the time which a detector registers as the arrival time of a quantum particle, is a long-debated problem. In this regard, Bohmian mechanics provides in a straightforward way the distribution of the time at which the particle actually does arrive at a given surface in 3-space in the absence of detectors. However, as we discuss here, since the presence of detectors can change the evolution of the wave function and thus the particle trajectories, it cannot be taken for granted that the arrival time of the Bohmian trajectories in the absence of detectors agrees with the one in the presence of detectors, and even less with the detection time. In particular, we explain why certain distributions that Das and Durr [7] presented as the distribution of the detection time in a case with spin, based on assuming that all three times mentioned coincide, are actually not what Bohmian mechanics predicts. Key words: Bohmian mechanics; POVM.
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1263129.728985
For the one-dimensional Facilitated Exclusion Process with initial state a product measure of density ρ = 1/2− δ, δ ≥ 0, there exists an infinite-time limiting state νρ in which all particles are isolated and hence cannot move. We study the variance V (L), under νρ, of the number of particles in an interval of L sites. Under ν /2 either all odd or all even sites are occupied, so that V (L) = 0 for L even and V (L) = 1/4 for L odd: the state is hyperuniform [21], since V (L) grows more slowly than L. We prove that for densities approaching 1/2 from below there exist three regimes in L, in which the variance grows at different rates: for L ≫ δ , V (L) ≃ ρ(1 − ρ)L, just as in the initial state; for A(δ) ≪ L ≪ δ , with A(δ) = δ− /3 p and A(δ) = 1 for L even, V (L) ≃ CL3/2 with C = 2 for L odd 2/π/3; and for L ≪ δ−2/3 with L odd, V (L) ≃ 1/4. The analysis is based on a careful study of a renewal process with a long tail. Our study is motivated by simulation results showing similar behavior in higher dimensions; we discuss this background briefly.
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1281175.728991
This question does not ask for the maximal number of eggs that is sufficient for baking this cake. Instead, Beck & Rullmann proposed a more sophisticated maximal informativity account, according to which (1) asks for the most informative number n such that n eggs are sufficient for the cake. This will in fact be the minimum number eggs needed. Along the way, Beck & Rullmann discussed the notion of sufficiency, proposing ideas that had not been made explicit before. They did this not because sufficiency is a primary target of their investigation but to make sure that the technical implementation of their theory of maximal informativity of questions is explicit and plausible.
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1316482.728996
Chairman of the KPA Group;
Senior Research Fellow, the Samuel Neaman Institute, Technion, Haifa;
Chairman, Data Science Society, Israel
What’s happening in statistical practice since the “abandon statistical significance” call
This is a retrospective view from experience gained by applying statistics to a wide range of problems, with an emphasis on the past few years. …
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1334837.72902
Preparing general relativity for quantization in the Hamiltonian approach leads to the ‘problem of time,’ rendering the world fundamentally timeless. One proposed solution is the ‘thermal time hypothesis,’ which defines time in terms of states representing systems in thermal equilibrium. On this view, time is supposed to emerge thermodynamically even in a fundamentally timeless context. Here, I develop the worry that the thermal time hypothesis requires dynamics – and hence time – to get off the ground, thereby running into worries of circularity.
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1450127.729031
This correspondence marks the return of physicists Richard C. Tolman and Percy W. Bridgman to the topic of dimensional analysis. In the preceding decades Tolman and Bridgman were at the center of debates concerning the methodological and metaphysical commitments of dimensional reasoning, beginning with Tolman’s controversial proposal that a “principle of similitude”—a principle asserting that global scale transformations of length quantities are dynamical and empirical symmetries—ought to be the foundational principle of dimensional analysis. Bridgman, inspired to clear up the mass of confusion he saw in the ensuing debate, wrote the first book in English on the topic: Dimensional Analysis (originally published 1922, with a revised edition published in 1931), which coined what is now the standard name for the method. This correspondence has yet to have been published or referred to in the literature on dimensional analysis and its history. With its publication I include this editorial introduction and some exegetical and contextualizing notes. This correspondence is not only significant because it clarifies some of the—largely metaphysical—issues left unsettled by the original debate between Tolman, Bridgman, and others, but it also highlights the practical significance of these issues for physicists in the early 20th century who were working to standardize the unit system used in the teaching and practices of physics and engineering—especially with respect to electromagnetic units. A Richard Chace Tolman (1881-1948) was Professor of Physical Chemistry and Mathematical Physics at the California Institute of Technology. Besides being one of the central figures in debates regarding the foundations of dimensional analysis, he was one of the first disseminators of relativity theory in the United States and served as a scientific advisor for the Manhattan Project. Tolman in fact first suggested the implosion method that used in the “Fat Man” bomb on Nagasaki (Monk 2014, 364).
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1450150.72904
I argue that dimensional analysis provides an answer to a skeptical challenge to the theory of model mediated measurement. The problem arises when considering the task of calibrating a novel measurement procedure, with greater range, to the results of a prior measurement procedure. The skeptical worry is that the agreement of the novel and prior measurement procedures in their shared range may only be apparent due to the emergence of systematic error in the exclusive range of the novel measurement procedure. Alternatively: what if the two measurement procedures are not in fact measuring the same quantity? The theory of model mediated measurement can only say that we assume that there is a common quantity. In contrast, I show that the satisfaction of dimensional homogeneity across the metrological extension is independent evidence for the so-called assumption. This is illustrated by the use of dimensional analysis in high pressure experiments. This results in an extension of the theory of model mediated measurement, in which a common quantity in metrological extension is no longer assumed, but hypothesized.
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1450177.72905
This paper recovers an important, century-old debate regarding the methodological and metaphysical foundations of dimensional analysis. Consideration of Richard Tolman’s failed attempt to install the principle of similitude—the relativity of size—as the founding principle of dimensional analysis both clarifies the method of dimensional analysis and articulates two metaphysical positions regarding quantity dimensions. Tolman’s position is quantity dimension fundamentalism. This is a commitment to dimensional realism and a set of fundamental dimensions which ground all further dimensions. The opposing position, developed primarily by Bridgman, is quantity dimension conventionalism. Conventionalism is an anti-realism regarding dimensional structure, holding our non-representational dimensional systems have basic quantity dimensions fixed only by convention. This metaphysical dispute was left somewhat unsettled. It is shown here that both of these positions face serious problems: fundamentalists are committed to surplus dimensional structure; conventionalists cannot account for empirical constraints on our dimensional systems nor the empirical success of dimensional analysis. It is shown that an alternative position is available which saves what is right in both: quantity dimension functionalism.
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1489104.729061
Artificial General Intelligence (AGI) is said to pose many risks, be they catastrophic, existential and otherwise. This paper discusses whether the notion of risk can apply to AGI, both descriptively and in the current regulatory framework. The paper argues that current definitions of risk are ill-suited to capture supposed AGI existential risks, and that the risk-based framework of the EU AI Act is inadequate to deal with truly general, agential systems.
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1609348.729072
We consider the fluctuations in the number of particles in a box of size L in Z , d ⩾ 1, in the (infinite volume) translation invariant stationary states of the facilitated exclusion process, also called the conserved lattice gas model. When started in a Bernoulli (product) measure at density ρ, these systems approach, as t → ∞, a ‘frozen’ state for ⩽ c, with c 1 2 for d 1 and ρc < 1/2 for d ⩾ 2. At ρ= ρc the limiting state is, as observed by Hexner and Levine, hyperuniform, that is, the variance of the number of particles in the box grows slower than L . We give a general description of how the variances at different scales of L behave as ρ ↗ c. On the largest scale, L≫ L , the fluctuations are normal (in fact the same as in the original product measure), while in a region L1 ≪ L ≪ L2, with both L1 and L2 going to infinity as ↗ c, the variance grows faster than normal. For 1≪ L ≪ L1 the variance is the same as in the hyperuniform system. (All results discussed are rigorous for d = 1 and based on simulations for d ⩾ 2.)
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1610003.729083
This paper seeks to determine a rational agent’s evidential constraints given her beliefs. Rationality is here construed as adherence to a principle of entropy maximisation. I determine the rational agent’s set of probability efunctions compatible with the evidence, ? , given the maximum entropy function and given some constraints on the shape of ? . I also consider agents employing a centre of mass approach to form their beliefs rather than entropy maximisation.