The Horizon Quantum Mechanics is an approach that allows one to analyse the gravitational radius of spherically symmetric systems and compute the probability that a given quantum state is a black hole. We first review the formalism and show how it reproduces a gravitationally inspired GUP relation. This results leads to unacceptably large fluctuations in the horizon size of astrophysical black holes if one insists in describing them as central singularities. On the other hand, if they are extended systems, (...) like in the corpuscular models, no such issue arises and one can in fact extend the formalism to include asymptotic mass and angular momentum with the harmonic model of rotating corpuscular black holes. The Horizon Quantum Mechanics then shows that, in simple configurations, the appearance of the inner horizon is suppressed and extremal geometries seem disfavoured. (shrink)

Rotations in Quantum Mechanics are a very well-known subject. When one is faced with rotations related to the SO group, for instance, all the underlying operators are well-known and built from their classical counterparts. However, when it comes to represent rotations related to the SU group, it is always argued that there is no classical counterpart from which the expressions for the quantum mechanical operators can be built. The approach is always done using matrix representation. In the way of this (...) aproach, one assumes that the operators related to SU are pseudovectors and end up with the weird result that only rotations by multiples of \ would bring the system to its original situation. In Olavo we have shown that any half-integral spin system can be represented in the Schrödinger picture by solving a Schrödinger equation with well defined expressions for the SU differential operators. It turned out that two of these operators are symmetric tensors, not pseudovectors or antisymmetric tensors. In this paper we use these results to dismiss with the \ conundrum. (shrink)

We consider the following question within both Newtonian physics and relativity theory. "Given two point particles X and Y, if Y is rotating relative to X, does it follow that X is rotating relative to Y?" As it stands the question is ambiguous. We discuss one way to make it precise and show that, on that reading at least, the answers given by the two theories are radically different. The relation of relative orbital rotation turns out to be symmetric (...) in Newtonian physics, but not in relativity theory. (shrink)

This study addresses the challenge of attitude tracking control for a rigid-flexible spacecraft with high-inertia rotating appendages. The Lagrange method was used to establish the kinematic and dynamic models of the spacecraft. The translation and rotation of the spacecraft, vibrations of solar panels, and imbalance caused by the rotating appendages, which cause a complex control problem, were considered. To address the complex control problem, a novel, fast nonsingular integral sliding mode control method is proposed to perform the attitude tracking function (...) of spacecraft. A sliding mode control law was established for the high-inertia appendages to maintain an appropriate angular velocity during rotation. Finally, the effectiveness of the proposed attitude control law was verified by numerical simulations for a spacecraft with high-inertia rotating appendages and symmetrical flexible solar panels. (shrink)

We have revised the problem of the motion of a heavy symmetric top. When formulating equations of the Lagrange top with the diagonal inertia tensor, the potential energy has more complicated form as compared with that assumed in the literature on dynamics of a rotating body. This implies the corresponding improvements in equations of motion. Using the Liouville’s theorem, we solve the improved equations in quadratures and present the explicit expressions for the resulting elliptic integrals.

It is tempting to think that a process of choosing a point at random from the surface of a sphere can be probabilistically symmetric, in the sense that any two regions of the sphere which differ by a rotation are equally likely to include the chosen point. Isaacs, Hájek, and Hawthorne (2022) argue from such symmetry principles and the mathematical paradoxes of measure to the existence of imprecise chances and the rationality of imprecise credences. Williamson (2007) has argued from (...) a related symmetry principle to the failure of probabilistic regularity. We contend that these arguments fail, because they rely on auxiliary assumptions about probability which are inconsistent with symmetry to begin with. We argue, moreover, that symmetry should be rejected in light of this inconsistency, and because it has implausible decision- theoretic implications. -/- The weaker principle of probabilistic invariance says that the probabilistic comparison of any two regions is unchanged by rotations of the sphere. This principle supports a more compelling argument for imprecise probability. We show, however, that invariance is incompatible with mundane judgments about what is probable. Ultimately, we find reason to be suspicious of the application of principles like symmetry and invariance to nonmeasurable regions. (shrink)

The atomic structure of a ‡ = 3, [110]/{112} grain boundary in a yttria-stabilized cubic zirconia bicrystal has been investigated by high-resolution transmission electron microscopy . It was found that the grain boundary migrated to form periodic facets, although the bicrystal was initially joined so as to have the symmetric boundary plane of {112}. The faceted boundary planes were indexed as {111}/{115}. The structure of the {111}/{115} grain boundary was composed of an alternate array of two types of structure (...) unit: {112}- and {111}-type structure units. HRTEM observations combined with lattice statics calculations verified that both crystals were relatively shifted by [110] along the rotation axis to form a stable grain-boundary structure. A weak-beam dark-field image revealed that there was a periodic array of dislocations along the grain boundary. The grain-boundary dislocations were considered to be introduced by the slight misorientation from the perfect ‡ = 3 orientation. The fact that the periodicity of the facets corresponded to that of the grain-boundary dislocations must indicate that the introduction of the grain-boundary dislocations is closely related to the periodicity of the facets. An atomic flipping model has been proposed for the facet growth from the initial ‡ = 3, {112} grain boundary. (shrink)

Recent work on the history of General Relativity by Renn, Sauer, Janssen et al. shows that Einstein found his field equations partly by a physical strategy including the Newtonian limit, the electromagnetic analogy, and energy conservation. Such themes are similar to those later used by particle physicists. How do Einstein's physical strategy and the particle physics derivations compare? What energy-momentum complex did he use and why? Did Einstein tie conservation to symmetries, and if so, to which? How did his work (...) relate to emerging knowledge of the canonical energy-momentum tensor and its translation-induced conservation? After initially using energy-momentum tensors hand-crafted from the gravitational field equations, Einstein used an identity from his assumed linear coordinate covariance x'=Mx to relate it to the canonical tensor. Usually he avoided using matter Euler-Lagrange equations and so was not well positioned to use or reinvent the Herglotz-Mie-Born understanding that the canonical tensor was conserved due to translation symmetries, a result with roots in Lagrange, Hamilton and Jacobi. Whereas Mie and Born were concerned about the canonical tensor's asymmetry, Einstein did not need to worry because his Entwurf Lagrangian is modeled not so much on Maxwell's theory as on a scalar theory. Einstein's theory thus has a symmetric canonical energy-momentum tensor. But as a result, it also has 3 negative-energy field degrees of freedom. Thus the Entwurf theory fails a 1920s-30s a priori particle physics stability test with antecedents in Lagrange's and Dirichlet's stability work; one might anticipate possible gravitational instability. This critique of the Entwurf theory can be compared with Einstein's 1915 critique of his Entwurf theory for not admitting rotating coordinates and not getting Mercury's perihelion right. One can live with absolute rotation but cannot live with instability. Particle physics also can be useful in the historiography of gravity and space-time, both in assessing the growth of objective knowledge and in suggesting novel lines of inquiry to see whether and how Einstein faced the substantially mathematical issues later encountered in particle physics. This topic can be a useful case study in the history of science on recently reconsidered questions of presentism, whiggism and the like. Future work will show how the history of General Relativity, especially Noether's work, sheds light on particle physics. (shrink)

Measurement of gravitomagnetic field is of fundamental importance as a test of general relativity. Here we present a new theoretical project for performing such a measurement based on detection of the electric field arising from the interplay between the gravitomagnetic and magnetic fields in the stationary axial-symmetric gravitational field of a slowly rotating massive body. Finally it is shown that precise magnetometers based on superconducting quantum interferometers could not be designed for measurement of the gravitomagnetically induced magnetic field in (...) the cavity of a charged capacitor since they measure the circulation of a vector potential of electromagnetic field, i.e., an invariant quantity including the sum of electric and magnetic fields, and the general-relativistic magnetic part will be totally cancelled by the electric one which is in good agreement with the experimental results. (shrink)

We review some recent developments in the conformal gravity theory that has been advanced as a candidate alternative to standard Einstein gravity. As a quantum theory the conformal theory is both renormalizable and unitary, with unitarity being obtained because the theory is a PT symmetric rather than a Hermitian theory. We show that in the theory there can be no a priori classical curvature, with all curvature having to result from quantization. In the conformal theory gravity requires no independent (...) quantization of its own, with it being quantized solely by virtue of its being coupled to a quantized matter source. Moreover, because it is this very coupling that fixes the strength of the gravitational field commutators, the gravity sector zero-point energy density and pressure fluctuations are then able to identically cancel the zero-point fluctuations associated with the matter sector. In addition, we show that when the conformal symmetry is spontaneously broken, the zero-point structure automatically readjusts so as to identically cancel the cosmological constant term that dynamical mass generation induces. We show that the macroscopic classical theory that results from the quantum conformal theory incorporates global physics effects that provide for a detailed accounting of a comprehensive set of 138 galactic rotation curves with no adjustable parameters other than the galactic mass to light ratios, and with the need for no dark matter whatsoever. With these global effects eliminating the need for dark matter, we see that invoking dark matter in galaxies could potentially be nothing more than an attempt to describe global physics effects in purely local galactic terms. Finally, we review some recent work by ’t Hooft in which a connection between conformal gravity and Einstein gravity has been found. (shrink)

This paper introduces a possible alternative model of gravity based on the theory of fractional-dimension spaces and its applications to Newtonian gravity. In particular, Gauss’s law for gravity as well as other fundamental classical laws are extended to a D-dimensional metric space, where D can be a non-integer dimension. We show a possible connection between this Newtonian Fractional-Dimension Gravity (NFDG) and Modified Newtonian Dynamics (MOND), a leading alternative gravity model which accounts for the observed properties of galaxies and other astrophysical (...) structures without requiring the dark matter hypothesis. The MOND acceleration constant $${a_{0}} \simeq 1.2 \times 10^{-10} \text {m}\, \text{s}^{-2}$$ can be related to a natural scale length $$l_{0}$$ in NFDG, i.e., $$a_{0} \approx GM/l_{0}^{2}$$, for astrophysical structures of mass M, and the deep-MOND regime is present in regions of space where the dimension is reduced to $$D \approx 2$$. For several fundamental spherically-symmetric structures, we compare MOND results, such as the empirical Radial Acceleration Relation (RAR), circular speed plots, and logarithmic plots of the observed radial acceleration $$g_{obs}$$ vs. the baryonic radial acceleration $$g_{bar}$$, with NFDG results. We show that our model is capable of reproducing these results using a variable local dimension $$D\left( w\right)$$, where $$w =r/l_{0}$$ is a dimensionless radial coordinate. At the moment, we are unable to derive explicitly this dimension function $$D\left( w\right)$$ from first principles, but it can be obtained empirically in each case from the general RAR. Additional work on the subject, including studies of axially-symmetric structures, detailed galactic rotation curves fitting, and a possible relativistic extension, will be needed to establish NFDG as a viable alternative model of gravity. (shrink)

Concepts of stability and symmetry in irreversible thermodynamics are developed through the analysis of system energy flows. The excess power function, derived from a local energy conservation equation, is shown to yield necessary and sufficient stability criteria for linear and nonlinear irreversible processes. In the absence of symmetry-destroying external forces, the linear range may be characterized by a set of phenomenological coefficient symmetries relating coupled forces and displacements, velocities, and accelerations, whereas rotational phenomena in nonlinear processes may be characterized by (...) skew-symmetric components of the phenomenological coefficients. A physical interpretation of the nature of the skew-symmetric parts is given and the variational principle of minimum dissipation of energy is related to a stability criterion. (shrink)

Lanczos, C. Einstein's path from special to general relativity.--Balazs, N. L. The acceptability of physical theories: Poincaré versus Einstein.--Ellis, G. F. R. Global and non-global problems in cosmology, by G. F. R. Ellis and D. W. Sciama.--Ehlers, J. The geometry of free fall and light propagation, by J. Ehlers, F. A. E. Pirani and A. Schild.--Trautman, A. Invariance of Lagrangian systems.--Penrose, R. The geometry of impulsive gravitational waves.--Exact solutions of the Einstein-Maxwell equations for an accelerated charge.--Taub, A. H. Plane-symmetric (...) similarity solutions for self-gravitating fluids.--Robinson, I. Equations of motion in the linear approximation, by I. Robinson and J. R. Robinson.--Florides, P. W. Rotating bodies in general relativity.--Chandrasekhar, S. A limiting case of relativistic equilibrium.--Israel, W. The relativistic Boltzmann equation.--Thompson, W. B. The self-consistent test-particle approach to relativistic kinetic theory. (shrink)

The vector product method developed in previous articles for space rotations and Lorentz transformations is extended to the cases of four-vectors, anti-symmetric tensors, and their transformations in Minkowski space. The electromagnetic fields are expressed in “six-vector” form using the notationH +iE, and this vector form is shown to be relativistically invariant. The wave equations of electromagnetism are derived using these vector products. The following three equations are deduced, which summarize electrodynamics in a compact form: (1) Maxwell's four equations expressed (...) as one, (2) the scalar and vector potential wave equations combined into one relation, and (3) the wave equations for the electric and magnetic fields and the continuity equation combined together. Space inversion, time reversal, and magnetic monopoles are also treated. (shrink)

In earlier work, representations ofr nucleons were constructed by taking therth Kronecker product of self-representations of the complete homogeneous Lorentz groupL 0 , where these were in the form of a four-component Dirac spinor with components corresponding to the internal symmetries of spin, parity, and charge. When permutations that include every possible exchange of spin, charge, and coordinate, are factored out, the4 F coordinates of flat Minskowski space are contracted by an isometry φ such that energy levels correspond to troughs (...) or saddle points in the new nuclear manifoldM. This is a symmetric space, and using the critical point theory of Morse for the neighborhood of an energy level, it is found that the symmetry σ associated with φ separatesM into just the sets of rotational and vibrational levels. Furthermore, by employing only one parameter, corresponding to the range of energies encountered, good agreement is found with the experimental levels and state labels of 10 B, 10 Be, 10 C, 10 C, and 10 O. The supermultiplet theory of Wigner is a necessary condition for the existence of the states. (shrink)

One of the long-standing problems in particle physics is the covariant description of higher spin states. The standard formalism is based upon totally symmetric Lorentz invariant tensors of rank-K with Dirac spinor components, $\psi _{\mu _1 \cdots \mu _K } $ , which satisfy the Dirac equation for each space time index. In addition, one requires $\partial ^{\mu _1 } \psi _{\mu _1 \cdots \mu _K } = 0{\text{ }}and{\text{ }}\gamma ^{\mu _1 } \psi _{\mu _1 \cdots \mu _K (...) } = 0$ . The solution obtained this way (so called Rarita–Schwinger framework) describes “has–been” spin-(K+ $ - \frac{1}{2}$ ) particles in the rest frame and particles of indefinite (fuzzy) spin elsewhere. Problems occur when $\psi _{\mu _1 \cdots \mu _K } $ constrained this way are placed within an electromagnetic field. In this case, the energy of the spin-(K+ $ - \frac{1}{2}$ ) state becomes imaginary and it propagates acausally (Velo–Zwanziger problem). Here I consider two possible avenues for avoiding the above problems. First I make the case that specifically for baryon excitations there seems to be no urgency so far for a formalism that describes isolated higher-spin states as all the observed nucleon and Δ(1232) excitations (up to Δ(1600)) are exhausted by unconstrained ψ μ , $\psi _\mu ,\psi _{\mu _1 \cdots \mu _3 } {\text{ }}and{\text{ }}\psi _{\mu _1 \cdots \mu _5 } ,$ , structures which originate from rotational and vibrational excitations of an underlying quark–diquark string. Second, I show that the $\gamma ^{\mu _1 } \psi _{\mu _1 \cdots \mu _K } = 0$ constraint is a short-hand of a more general definition of the parity-singlet invariant subspace of the squared Pauli–Lubanski vector, W 2. I consider the simplest case of K=1 and construct the covariant projector onto that very state as $ - \frac{1}{3}(\frac{1}{{m^2 }}W^2 + \frac{3}{4})$ . I suggest to work in the sixteen dimensional vector space, Ψ, of the direct product of the four-vector, A μ , with the Dirac spinor, ψ, i.e., Ψ=A μ ⊗ψ, rather than keeping space-time and spinor indices separated and to consider $( - \frac{1}{3}(\frac{1}{{m^2 }}W^2 + \frac{3}{4}) - 1)\Psi = 0$ as the principal wave equation without invoking any further supplementary conditions. In gauging the equation minimally and, in calculating the determinant, one obtains the energy-momentum dispersion relation. The latter turned out to be well-behaved and free from pathologies, thus avoiding the classical Velo–Zwanziger problem. (shrink)

Symmetric instruction machines (SIAs) and symmetric Turing machines (STMs) are models of computation involving concepts derived from those of classical Turing machines such as tape (memory) and head (processor), but with different functional and structural characteristics. The former model (SIAs) introduced in this paper and preferred by Mark Burgin is a result of a reformulation of the latter model (STMs) published in several articles by the second author in the past. The properties of both models are analyzed and (...) compared. The word “symmetric” in both cases represents the feature of the design which is distinct from classical Turing machines where only cells on the tape change under the action of the head. In both models, symmetric computing involves changes of the tape and parallel (“symmetric”) changes of instructions listed in the head. The key difference between SIAs and STMs is in the dynamic of the changes, which in the former model has the form of compound one-way actions and in the latter model, it has the form of uniform mutual interactions, which only in specific realizations can be separated into a pair of actions. Because of the untimely passing of Mark Burgin, the discussion of the two models and cooperation on the paper has never been finished. For this reason, the arguments of both authors are reported even though, in some cases, they are mutually inconsistent or even contradictory. (shrink)

Determining how we use our body to support cognition represents an important part of understanding the embodied and embedded nature of cognition. In the present investigation, we pursue this question in the context of a common perceptual task. Specifically, we report a series of experiments investigating head tilt (i.e., external normalization) as a strategy in letter naming and reading stimuli that are upright or rotated. We demonstrate that the frequency of this natural behavior is modulated by the cost of stimulus (...) rotation on performance. In addition, we demonstrate that external normalization can benefit performance. All of the results are consistent with the notion that external normalization represents a form of cognitive offloading and that effort is an important factor in the decision to adopt an internal or external strategy. (shrink)

Two new first-order paraconsistent logics with De Morgan-type negations and co-implication, called symmetric paraconsistent logic (SPL) and dual paraconsistent logic (DPL), are introduced as Gentzen-type sequent calculi. The logic SPL is symmetric in the sense that the rule of contraposition is admissible in cut-free SPL. By using this symmetry property, a simpler cut-free sequent calculus for SPL is obtained. The logic DPL is not symmetric, but it has the duality principle. Simple semantics for SPL and DPL are (...) introduced, and the completeness theorems with respect to these semantics are proved. The cut-elimination theorems for SPL and DPL are proved in two ways: One is a syntactical way which is based on the embedding theorems of SPL and DPL into Gentzen’s LK, and the other is a semantical way which is based on the completeness theorems. (shrink)

Metaphysical orthodoxy maintains that the relation of ontological dependence is irreflexive, asymmetric, and transitive. The goal of this paper is to challenge that orthodoxy by arguing that ontological dependence should be understood as non- symmetric, rather than asymmetric. If we give up the asymmetry of dependence, interesting things follow for what we can say about metaphysical explanation— particularly for the prospects of explanatory holism.

In this article, the rotational invariance of entangled quantum states is investigated as a possible cause of the Pauli exclusion principle. First, it is shown that a certain class of rotationally invariant states can only occur in pairs. This is referred to as the coupling principle. This in turn suggests a natural classification of quantum systems into those containing coupled states and those that do not. Surprisingly, it would seem that Fermi–Dirac statistics follows as a consequence of this coupling (...) while the Bose–Einstein follows by breaking it. In Sec. 5, the above approach is related to Pauli's original spin-statistics theorem and finally in the last two sections, a theoretical justification, based on Clebsch–Gordan coefficients and the experimental evidence respectively, is presented. (shrink)

The rotating discs argument against perdurantism has been mostly discussed by metaphysicians, though the argument of course appeals to ideas from classical mechanics, especially about rotation. In contrast, I assess the RDA from the perspective of the philosophy of physics. I argue for three main conclusions. The first conclusion is that the RDA can be formulated more strongly than is usually recognized: it is not necessary to ‘imagine away’ the dynamical effects of rotation. The second is that in general relativity, (...) the RDA fails because of frame-dragging. The third conclusion is that even setting aside general relativity, the strong formulation of the RDA can after all be defeated, namely, by the perdurantist taking objects in classical mechanics to have only temporally extended temporal parts, which immediately blocks the RDA. Admittedly, this version of perdurantism defines persistence in a weaker sense of ‘definition’ than pointilliste versions that aim to define persistence assuming only instantaneous temporal parts. But I argue that temporally extended temporal parts can do the jobs within the endurantism– perdurantism debate that the perdurantist wants temporal parts to do and are supported by both classical and quantum mechanics. Introduction The story so far 2.1 The RDA 2.2 Intrinsic properties and the idea of velocity 2.2.1 The intrinsic–extrinsic distinction 2.2.2 Velocity to the rescue? 2.3 ‘Naturalism’ 2.4 The accompaniments of rotation 2.5 Two kinds of reply: against the consensus Describing rotation 3.1 Rotation is kinematic 3.2 Beware of rigidity 3.3 An improved RDA: allowing the actual accompaniments 3.4 The RDA fails in general relativity Perdurantism without tears: the classical case 4.1 Rejecting instantaneous temporal parts 4.2 Replying to the RDA 4.2.1 ‘Kinematics’ 4.2.2 ‘Dynamics’ 4.2.3 An ‘anti-pointilliste’ objection and reply 4.3 Intrinsic properties of non-instantaneous temporal parts 4.3.1 Can the perdurantist appeal to them? 4.3.2 Temporal intrinsicality at an instant is rare 4.3.3 A better reason for temporal intrinsicality 4.4 Non-instantaneous parts can do the jobs 4.4.1 Humean supervenience revisited 4.4.2 The problem of change 4.4.3 Puzzles of coincidence 4.5 Instantaneous velocity is hardly extrinsic Support from decoherence in quantum theory 5.1 Classical and quantum: relativizing the intrinsic–extrinsic distinction 5.1.1 Unitarity: momentum as temporally intrinsic 5.2 Position and existence as nomically extrinsic. (shrink)

Two rotational bands have been identified and characterized in the proton-magic N = Z + 1 nucleus Ni-57. These bands complete the systematics of well-and superdeformed rotational bands in the light nickel isotopes starting from doubly magic Ni-56 to Ni-60. High-spin states in Ni-57 have been produced in the fusion-evaporation reaction Si-28(S-32, 2p1n)Ni-57 and studied with the gamma-ray detection array GAMMASPHERE operated in conjunction with detectors for evaporated light charged particles and neutrons. The features of the rotational bands in Ni-57 (...) are compared to those of neighbouring isotopes and interpreted by means of configuration-dependent cranked Nilsson-Strutinsky calculations. The two observed high-spin bands are considered signature partners and assigned to configurations with one 1g(9/2) proton and one 1g(9/2) neutron, resulting in an unambiguous understanding of the energetically favoured signature alpha = -1/2 band but a somewhat less satisfactory description of the signature alpha = +1/2 band. (shrink)

This study examines the spontaneous use of embodied egocentric transformation in understanding false beliefs in the minds of others. EET involves the participants mentally transforming or rotating themselves into the orientation of an agent when trying to adopt his or her visuospatial perspective. We argue that psychological perspective taking such as false belief reasoning may also involve EET because of what has been widely reported in the embodied cognition literature, showing that our processing of abstract, propositional information is often grounded (...) in concrete bodily sensations which are not apparently linked to higher cognition. In Experiment 1, an agent placed a ball into one of two boxes and left. The ball then rolled out and moved either into the other box or back into the original one. The participants were to decide from which box they themselves or the agent would try to recover the ball. Results showed that false belief performance was affected by increased orientation disparity between the participants and the agent, suggesting involvement of embodied transformation. In Experiment 2, false belief was similarly induced and the participants were to decide if the agent would try to recover the ball in one specific box. Orientation disparity was again found to affect false belief performance. The present results extend previous findings on EET in visuospatial perspective taking and suggest that false belief reasoning, which is a kind of psychological perspective taking, can also involve embodied rotation, consistent with the embodied cognition view. (shrink)

It is a metaphysical orthodoxy that interesting non-symmetric relations cannot be reduced to symmetric ones. This orthodoxy is wrong. I show this by exploring the expressive power of symmetric theories, i.e. theories which use only symmetric predicates. Such theories are powerful enough to raise the possibility of Pythagrapheanism, i.e. the possibility that the world is just a vast, unlabelled, undirected graph.

The proposal to create a chamber selected by sortition would extend this democratic procedure into the legislative branch of government. However, there are good reasons to believe that, as currently conceived by John Gastil and Erik Olin Wright, the proposal will fail to realize sufficiently two fundamental democratic goods, namely, political equality and deliberative reasoning. It is argued through analysis of its historic and contemporary application that sortition must be combined with other institutional devices, in particular, rotation of membership and (...) limited mandate, in order to be democratically effective and to realize political equality and deliberative reasoning. An alternative proposal for a responsive sortition legislature is presented as more realistic and utopian: one that increases substantially the number of members, makes more extensive use of internal sortition and rotation, and recognizes the importance of establishing limited mandates. (shrink)

The rotating spot method of timing subjective events involves the subject’s watching a rotating spot on a computer and reporting the position of the spot at the instant when the subjective event of interest occurs. We conducted an experiment to investigate factors that may impact on the results produced by this method, using the subject’s perception of when they made a simple finger movement as the subjective event to be timed. Seven aspects of the rotating spot method were investigated, using (...) a factorial experiment. Four of these aspects altered the physical characteristics of the computer generated spot or clock face and the remaining three altered the instructions given to the participant. We found compelling evidence that one factor, whether the subject was instructed to report the instant when the finger movement was initiated or the instant when it was completed, resulted in a systematic shift in the response. Evidence that three other factors affect the observed variability in the response was also found. In addition, we observed that there are substantial systematic differences in the responses made by different subjects. We discuss the implications of our findings and make recommendations about the optimal way of conducting future experiments using the rotating spot method. Our overall conclusion is that our results strongly validate the rotating spot method of timing at least the studied variety of subjective event. (shrink)

The purpose of this paper is to explore two questions:(1) Is symmetrical communication in public relations practice inherently ethical?(2) Does symmetrical communication contribute to public relations effectiveness and organizational effectiveness? Three surveys are undertaken to test seven research hypotheses for the purpose of cross-validating research findings. The results suggest that symmetrical communication is inherently ethical. Moreover, symmetrical communication indeed contributes to several performance measures, which include positive market performance, overall organizational effectiveness, conflict resolution, crisis management, favorable organizational reputation, and positive (...) media exposure, with the last two measures only partially supported. (shrink)

The main purpose of this paper is to introduce a class of algebraic structures related to many-valued ukasiewicz algebras. They are symmetrical Heyting algebras with a set of modal operators indexed by a finite completely symmetric poset. A representation theorem is given for these (not functionally complete) algebras.

A time-symmetric formulation of nonrelativistic quantum mechanics is developed by applying two consecutive boundary conditions onto solutions of a time- symmetrized wave equation. From known probabilities in ordinary quantum mechanics, a time-symmetric parameter P0 is then derived that properly weights the likelihood of any complete sequence of measurement outcomes on a quantum system. The results appear to match standard quantum mechanics, but do so without requiring a time-asymmetric collapse of the wavefunction upon measurement, thereby realigning quantum mechanics with (...) an important fundamental symmetry. (shrink)

Presupposing that most predicates do not correspond directly to genuine relations, I argue that all genuine relations are symmetric. My main argument depends on the premise that there are no brute necessities, interpreted so as to require logical and metaphysical necessity to coincide for sentences composed entirely of logical vocabulary and primitive predicates. Given this premise, any set of purportedly primitive predicates by which one might hope to express the facts about non-symmetric relations order their relata will generate (...) an objectionable multiplication of possibilities. In the final section I give a different argument, based on the weaker premise that brute necessities should not be multiplied without necessity. (shrink)

In “Sideways Music”, Ned Markosian uses aesthetic intuitions about temporally-rotated music to argue that the metaphysics of time is different from the metaphysics of space. In response, I use aesthetic intuitions about spatially-rotated paintings to pose a dilemma for Markosian’s argument: either he accepts the intuitions about spatially-rotated paintings, in which case he must give up on some assumptions in his argument, or he rejects intuitions about spatially-rotated paintings, in which case an analogous response can be given regarding intuitions about (...) temporally-rotated music. That is, if Markosian wants to hold on to the assumptions that underwrite his argument, then he thereby offers his opponent the resources with which to resist his conclusion. As such, Markosian’s argument cannot offer a new independent consideration for adjudicating the metaphysical debate between the Dynamic Theorist and the Spacetime Theorist. [Unpublishable 2019]. (shrink)

I examine and discuss in this paper Orilia’s theory of external, non-symmetrical relations, that is based on ontological roles (O-Roles). I explore several attempts to interpret O-Roles from an ontological viewpoint and I reject them because of two problems concerning the status of asymmetrical relations (to be distinguished from non-symmetrical relations simpliciter) and of exemplification as an external, non-symmetrical relation. Finally, following Heil’s and Lowe’s characterization of modes as particular properties that ontologically depend on their “bearers”, I introduce relational modes (...) in order to define a new solution to the problems of the ontological status of both external, non-symmetrical relations and O-Roles. I also deal with five objections raised by Fraser MacBride against relational modes and O-Roles and I elaborate an analysis of the relations of being to the left of and being to the right of. (shrink)

Mental rotation of emotional and neutral stimuli The main aim of the study was to create and validate emotional version of mental rotation task. As all previously conducted experiments utilized neutral material only, such an attempt seemed necessary to confirm the generality of mental rotation effect and its properties. Emotional MRT was constructed using photos of negative facial expressions; a compatible neutral MRT was also created, for detailed comparisons. 2- and 3-dimensional figures and hexagrams served as affect-free stimuli. In three (...) experiments, emotional MRT version was proven to be valid, whereas only hexagram-based neutral MRT version yielded the expected results. A number of differences between the two versions emerged, concerning response times, accuracy and difficulty of trials. The neutral/emotional MRT procedure, although needing more research, seems to give stable results, making the study of content-bound imagery possible. (shrink)

The completeness of the axiomatization of contingency logic over symmetric frames has been thought of as a nontrivial job, the unimodal case of which cannot be generalized to the finitely multimodal case, which in turn cannot be generalized to the infinitely multimodal case. This paper deals with the completeness of symmetric contingency logic with unlimitedly many modalities, no matter whether the set of modalities is finite or infinite.

We consider the historic Harress-Sagnac experiment in the light of our absolute space-time theory, proposing two modifications, and we give an account of its recent practical performance. We show that the effect of the rotating disk experiment is a direct result of the light velocity's direction dependence and we point out that our recently performed coupled-mirrors experiment, with whose help for the first time we have measured the Earth's absolute velocity, can be considered as a logical result of the rotating (...) disk experiment. (shrink)

In this paper, we define the notions of (l,r)-symmetric bi-derivations and (r,l)-symmetric bi-derivations on UP-algebras and investigate some properties of them. For these derivations, we introduce the sets Kerd(U), Fixd(U) and FixD(U). Moreover, we examine with examples whether these sets are UP-subalgebra or UP-ideal.

A gedanken experiment that distinguishes locally between acceleration of rotation and linear acceleration is described and discussed.

Symmetric generalized Galois logics (i.e., symmetric gGl s) are distributive gGl s that include weak distributivity laws between some operations such as fusion and fission. Motivations for considering distribution between such operations include the provability of cut for binary consequence relations, abstract algebraic considerations and modeling linguistic phenomena in categorial grammars. We represent symmetric gGl s by models on topological relational structures. On the other hand, topological relational structures are realized by structures of symmetric gGl s. (...) We generalize the weak distributivity laws between fusion and fission to interactions of certain monotone operations within distributive super gGl s. We are able to prove appropriate generalizations of the previously obtained theorems—including a functorial duality result connecting classes of gGl s and classes of structures for them. (shrink)

There are two ways to characterize symmetric relations. One is intensional: necessarily, _Rxy_ iff _Ryx_. In some discussions of relations, however, what is important is whether or not a relation gives rise to the same completion of a given type (fact, state of affairs, or proposition) for each of its possible applications to some fixed relata. Kit Fine calls relations that do ‘strictly symmetric’. Is there is a difference between the notions of necessary and strict symmetry that would (...) prevent them from being used interchangeably in such discussions? I show that there is. While the notions coincide assuming an intensional account of relations and their completions, according to which relations/completions are identical if they are necessarily coinstantiated/equivalent, they come apart assuming a hyperintensional account, which individuates relations and completions more finely on the basis of relations’ real definitions. I establish this by identifying two definable relations, each of which is necessarily symmetric but nonetheless results in distinct facts when it applies to the same objects in opposite orders. In each case, I argue that these facts are distinct because they have different grounds. (shrink)

Gödel logic is the extension of intuitionistic logic by the linearity axiom. Symmetric Gödel logic is a logical system, the language of which is an enrichment of the language of Gödel logic with their dual logical connectives. Symmetric Gödel logic is the extension of symmetric intuitionistic logic. The proof-intuitionistic calculus, the language of which is an enrichment of the language of intuitionistic logic by modal operator was investigated by Kuznetsov and Muravitsky. Bimodal symmetric Gödel logic is (...) a logical system, the language of which is an enrichment of the language of Gödel logic with their dual logical connectives and two modal operators. Bimodal symmetric Gödel logic is embedded into an extension of Gödel–Löb logic, the language of which contains disjunction, conjunction, negation and two modal operators. The variety of bimodal symmetric Gödel algebras, that represent the algebraic counterparts of bimodal symmetric Gödel logic, is investigated. Description of free algebras and characterization of projective algebras in the variety of bimodal symmetric Gödel algebras is given. All finitely generated projective bimodal symmetric Gödel algebras are infinite, while finitely generated projective symmetric Gödel algebras are finite. (shrink)

Counterfactuals in quantum theory are briefly reviewed and it is argued that they are very different from counterfactuals considered in the general philosophical literature. The issue of time symmetry of quantum counterfactuals is considered and a novel time-symmetric definition of quantum counterfactuals is proposed. This definition is applied for analyzing several controversies related to quantum counterfactuals.

According to some representationalists (M. Tye, Ten problems of consciousness, MIT Press, Massachusetts, USA, 1995; W.G. Lycan, Consciousness and experience, MIT Press, Cambridge, Massachusetts, USA, 1996; F. Dretske, Naturalising the mind, MIT Press, Massachusetts, USA 1995), qualia are identical to external environmental states or features. When one perceives a red rose for instance, one is visually representing the actual redness of the rose. The represented redness of the rose is the actual redness of the rose itself. Thus redness is not (...) a property of one’s experience but an externally constituted property of the perceived physical object. In this sense, qualia are out there, in the external world. Here, I argue that the main representationalist arguments to this effect, if successful, establish no more than a symmetrical supervenience relation between representational content and qualia, and that a supervenience relation alone (albeit symmetrical) doesn’t suffice for identity. This supervenience thesis between qualia and representational content leaves open the question as to the essential nature of qualia. (shrink)

Motor imagery provides a direct insight into action representations. The aim of the present study was to investigate the level of impairment of action monitoring in schizophrenia by evaluating the performance of schizophrenic patients on mental rotation tasks. We raised the following questions: Are schizophrenic patients impaired in motor imagery both at the explicit and at the implicit level? Are body parts more difficult for them to mentally rotate than objects? Is there any link between the performance and the hallucinating (...) symptom profile? The schizophrenic patients displayed the same pattern of performance as the control subjects . More particularly, schizophrenic patients’ reaction time varied as a function of the angular disparity of the stimuli. On the other hand, they were significantly slower and less accurate. Interestingly, patients suffering from hallucinations made significantly more errors than non-hallucinatory patients. We discussed these latter results in terms of deficit of the forward model. We emphasized the necessity to distinguish different levels of action, more or less impaired in schizophrenia. (shrink)

This paper presents a new Symmetrical Interpretation (SI) of relativistic quantum mechanics which postulates: quantum mechanics is a theory about complete experiments, not particles; a complete experiment is maximally described by a complex transition amplitude density; and this transition amplitude density never collapses. This SI is compared to the Copenhagen Interpretation (CI) for the analysis of Einstein’s bubble experiment. This SI makes several experimentally testable predictions that differ from the CI, solves one part of the measurement problem, resolves some inconsistencies (...) of the CI, and gives intuitive explanations of some previously mysterious quantum effects. (shrink)