The concept of inertial frame of reference in classical physics and special theory of relativity is analysed. It has been shown that this fundamental concept of physics is not clear enough. A definition of inertial frame of reference is proposed which expresses its key inherent property. The definition is operational and powerful. Many other properties of inertial frames follow from the definition, or it makes them plausible. In particular, the definition shows why physical (...) laws obey space and time symmetries and the principle of relativity, it resolves the problem of clock synchronization and the role of light in it, as well as the problem of the geometry of inertial frames. (shrink)

The demonstration that slow transport of clocks can be used to define simultaneity in inertial frames of reference leads to the question of whether clock transport can similarly be used in noninertial frames. It is shown that there are certain types of reference frames in which the clock-transport method cannot be used in a self-consistent manner. It is also shown that there are other types of noninertial frames in which the clock-transport method will succeed. The discussion includes (...) noninertial frames in flat space-time as well as the case of curved space-times. (shrink)

A “frame of reference” is a standard relative to which motion and rest may be measured; any set of points or objects that are at rest relative to one another enables us, in principle, to describe the relative motions of bodies. A frame of reference is therefore a purely kinematical device, for the geometrical description of motion without regard to the masses or forces involved. A dynamical account of motion leads to the idea of an “ (...) class='Hi'>inertial frame,” or a reference frame relative to which motions have distinguished dynamical properties. For that reason an inertial frame has to be understood as a spatial reference frame together with some means of measuring time, so that uniform motions can be distinguished from accelerated motions. The laws of Newtonian dynamics provide a simple definition: an inertial frame is a reference-frame with a time-scale, relative to which the motion of a body not subject to forces is always rectilinear and uniform, accelerations are always proportional to and in the direction of applied forces, and applied forces are always met with equal and opposite reactions. It follows that, in an inertial frame, the center of mass of a system of bodies is always at rest or in uniform motion. It also follows that any other frame of reference moving uniformly relative to an inertial frame is also an inertial frame. For example, in Newtonian celestial mechanics, taking the “fixed stars” as a frame of reference, we can determine an inertial frame whose center is the center of mass of the solar system; relative to this frame, every acceleration of every planet can be accounted for as a gravitational interaction with some other planet in accord with Newton 's laws of motion. (shrink)

The obvious metaphysical differences between Newton and Leibniz concerning space, time, and motion reflect less obvious differences concerning the relation between geometry and physics, expressed in the questions: what are the invariant quantities of classical mechanics, and what sort of geometrical frame of reference is required to represent those quantities? Leibniz thought that the fundamental physical quantity was “living force” (mv2), of which every body was supposed to have a definite amount; this notion violates the classical principle of (...) relativity, since it makes a physical distinction between uniform velocity and absolute rest. But Leibniz did not try to represent this physical quantity in a spatio-temporal reference frame, assuming, instead, that all such frames are equivalent so long as they agree on the relative motions (changes in the mutual Euclidean distances) among bodies. (shrink)

In his general theory of relativity Einstein sought to generalize the special-relativistic equivalence of inertial frames to a principle according to which all frames of reference are equivalent. He claimed to have achieved this aim through the general covariance of the equations of GR. There is broad consensus among philosophers of relativity that Einstein was mistaken in this. That equations can be made to look the same in different frames certainly does not imply in general that such frames (...) are physically equivalent. We shall argue, however, that Einstein's position is tenable. The equivalence of arbitrary frames in GR should not be equated with relativity of arbitrary motion, though. There certainly are observable differences between reference frames in GR. The core of our defense of Einstein's position will be to argue that such differences should be seen as fact-like rather than law-like in GR. By contrast, in classical mechanics and in special relativity the differences between inertial systems and accelerated systems have a law-like status. The fact-like character of the differences between frames in GR justifies regarding them as equivalent in the same sense as inertial frames in SR. (shrink)

In his general theory of relativity (GR) Einstein sought to generalize the special-relativistic equivalence of inertial frames to a principle according to which all frames of reference are equivalent. He claimed to have achieved this aim through the general covariance of the equations of GR. There is broad consensus among philosophers of relativity that Einstein was mistaken in this. That equations can be made to look the same in different frames certainly does not imply in general that such (...) frames are physically equivalent. We shall argue, however, that Einstein's position is tenable. The equivalence of arbitrary frames in GR should not be equated with relativity of arbitrary motion, though. There certainly are observable differences between reference frames in GR (differences in the way particles move and fields evolve). The core of our defense of Einstein's position will be to argue that such differences should be seen as fact-like rather than law-like in GR. By contrast, in classical mechanics and in special relativity (SR) the differences between inertial systems and accelerated systems have a law-like status. The fact-like character of the differences between frames in GR justifies regarding them as equivalent in the same sense as inertial frames in SR. (shrink)

It is suggested that the mathematically abstract coordinate frames of reference commonly visualized to be centered at the celestial bodies have real counterparts in the shape of well-defined rigid spatial resonant singularities of infinite extension, which accommodate the matter waves from the superimposition of which the body residing at the coordinate origin results. A universally valid inertial reference frame system is proposed. Qualitative explanations are offered for the inertial and gravitational forces, their observed proportionality, and (...) for the occurrence of second-order gravitational effects in the vicinity of massive bodies. The universal redshift is assumed to result from a closure condition of the eigenspaces introduced. (shrink)

We present a fully relational definition of inertial systems based in the No Arbitrariness Principle, that eliminates the need for absolute inertial frames of reference or distinguished reference systems as the ``fixed stars'' in order to formulate Newtonian mechanics. The historical roots of this approach to mechanics are discussed as well. The work is based in part in the constructivist perspective of space advanced by Piaget. We argue that inertial systems admit approximations and that what (...) is of practical use are precisely such approximations. We finally discuss a slightly larger class of systems that we call ``relatively inertial'' which are the fundamental systems in a relational view of mechanics. (shrink)

Dispositions can combine as vector sums. Recent authors on dispositions, such as George Molnar and Stephen Mumford, have responded to this feature of dispositions by introducing a distinction between effects and contributions to effects, and by identifying disposition-manifestations with the latter. But some have been sceptical of the reality or knowability of component vectors; Jennifer McKitrick (forthcoming) presses these concerns against the conception of manifestations as contributions to effects. In this paper, I aim to respond to McKitrick's arguments and to (...) defend the metaphysical and epistemological propriety of component vectors. My strategy appeals to varying kinematic frames of reference. By transforming to the appropriate non-inertial frame, component acceleration vectors can be transformed into resultant acceleration vectors, and in such frames they become directly observable. Being a component acceleration vector and being a resultant acceleration vector are both frame-dependent properties of properties; they are not to be thought of as intrinsic or fundamental properties of an acceleration vector, but as artefacts of our frame-dependent notation for representing vector quantities. To conclude the paper, I defend the view proposed against two styles of objection. The first objection resurrects scepticism about component vectors as scepticism about fundamental component vectors. The second objection questions the need for reference frames in the explanation by invoking a 'counterfactual' theory of contributions. (shrink)

The Draft Common Frame of Reference is just published. Now the creation of the final Common Frame of Reference is one of the most important issues in the field of European Private Law. The volume discusses the key question as to what extent the CFR can and should reflect existing EC Contract Law, and to what extent the DCFR has already incorporated the acquis communautaire. The contributions to this volume try to provide answers to this question (...) by analyzing different controversial areas such as the conclusion and content of the contract, non-performance, remedies, damages and the relation to International Private Law. (shrink)

The problem for the CNS in any particular movement task is to coordinate the various frames of reference appropriate to the task. Control variables are determined by this coordination. The coordination problem varies greatly from task to task, and so no single set of control variables is likely to account for a broad range of movement tasks.

Various annoyingly incorrect statements of Stoffregen & Bardy are corrected, for example, that perception researchers commonly use the term to denote motion without any frame of reference, confuse earth-relative and gravity-relative motion, err with respect to the frame of reference implied by their subject is motion responses, believe in sense specific motion percepts, and do not investigate sensory interactions at neurophysiological levels. In addition, much of the target article seems to concern metaphysics rather than empirical science.

Journal Name: Cognitive Linguistics Issue: Ahead of print.

Models of central control variables (CVs) that are expressed in positional reference frames and rely on proprioception as the dominant specifier of muscle activation patterns have not yet been shown to be adequate for the description of fast, voluntary movement, even of single joints. An alternative model with illustrative data is proposed.

The paper investigates the ethical decisions of Millennials, who are not only part of an expanding cohort of the workforce, but also represent potential future managers with a growing influence on work practices and employment relationships. In the conceptual model, we propose that three ethical frames of reference, represented by perceived organisational ethics, perceived employee ethics and reflective moral attentiveness, antecede ethical judgements, which further influence the ethical intentions of Millennials. Using structural equation modelling, we test the model for (...) three different business ethics scenarios: paying a consulting fee, dumping hazardous waste, and running an offensive advertising campaign. The findings confirm the link between ethical judgements and intentions across the board, while the influence of the ethical frames of reference varies among the scenarios. We propose that the differences in the predictive ability of the ethical frames of reference depend on the nature of the ethical issue, which holds important implications for today's managers in their attempts to encourage ethical behaviour of Millennial employees. (shrink)

In a previous work, we have shown that the null result of the Michelson–Morley experiment in vacuum is deeply connected with the notion of time. The same is true for the postulate of constancy of the two-way speed of light in vacuum in all frames independently of the state of motion of the emitting body. The argumentation formerly given is very general and has to be true not only within Special Relativity and its “equivalence” of all inertial frames, but (...) as well as in Lorentz-Poincaré scenario of a preferred reference frame. This paper is the second of a trilogy intending to revisit the foundations of Special Relativity, and addresses the question of the constancy of the one-way speed of light and of the differences and similarities between both scenarios. Although they manifestly differ in philosophy, it is debated why and how the assumption of a “special system of reference experimentally inaccessible” is indeed compatible with Einstein’s Special Relativity, as beautifully outlined and discussed by Bell [Speakable and Unspeakable in Quantum Mechanics (Cambridge University Press, Cambridge, 1988)]. This rather trivial statement is still astonishing nowadays to a big majority of scientists. The purpose of this work is to bring such assertion into perspective, widening the somewhat narrow view of Special Relativity often presented in textbooks and scientific papers. (shrink)

While geocentric and relative frames of reference have figured prominently in the literature on spatial language and cognition, the intrinsic frame of reference has received less attention, though various subtypes of the intrinsic frame have been proposed. This paper presents a revised classification of the intrinsic frame, distinguishing between three subtypes: a ‘direct’ subtype, an ‘object-centered’ subtype and a ‘figure-anchored’ subtype, with a cross-cutting distinction between ‘function-based’ and ‘shape-based’ systems. In addition, the ‘FIBO’ system in (...) Dhivehi is analyzed as an example of a borderline case, with some important features of the intrinsic frame but also some differences, presenting a challenge for existing frame of reference classifications. The rotational properties of these various systems are also considered. The analysis underscores the considerable diversity within intrinsic systems but also points to a closer relationship between intrinsic and extrinsic frames than has previously been appreciated. This may have implications for broader theoretical issues including how frames of reference are acquired, how speech communities come to use different frames and whether patterns of frame use in discourse shape patterns of non-verbal frame use. (shrink)

Using various official sources, the article explores competing conceptions of the 'under- achieving ' school which have been operationalised in recent years. It suggests that there have been multiple, potentially conflicting definitions in policy discourse to which recent innovations have merely added a further layer of complexity. Using a simple conceptual framework comparing judgements made within 'standards' and 'progress' frameworks for evaluating schools' performance, it highlights the very limited range of conditions where judgements made within one tradition would complement those (...) made within the other. As the educational system begins to turn increasingly to use of so-called 'value-added' approaches as a way forward, the implications of these analyses for policy development, particularly in relation to the alleviation of social and educational disadvantage, are considered. (shrink)

In De gravitatione, Newton contends that Descartes' physics is fundamentally untenable since the "fixed" spatial landmarks required to ground the concept of inertial motion cannot be secured in the constantly changing Cartesian plenum. Likewise, it is has often been alleged that the collision rules in Descartes' Principles of Philosophy undermine the "relational" view of space and motion advanced in this text. This paper attempts to meet these challenges by investigating the theory of connected gears (or "kinematics of mechanisms") for (...) a potential Cartesian method of positing the permanent reference frames necessary to uphold Descartes' conservation law for the quantity of motion. In particular, the insights gained from an examination of the kinematics of mechanisms will provide the Cartesian with much needed resources to counter the two threats posed above. (shrink)

Albert Einstein's bold assertion of the form-invariance of the equation of a spherical light wave with respect to inertial frames of reference became, in the space of six years, the preferred foundation of his theory of relativity. Early on, however, Einstein's universal light-sphere invariance was challenged on epistemological grounds by Henri Poincaré, who promoted an alternative demonstration of the foundations of relativity theory based on the notion of a light-ellipsoid. Drawing in part on archival sources, this paper shows (...) how an informal, international group of physicists, mathematicians, and engineers, including Einstein, Paul Langevin, Poincaré, Hermann Minkowski, Ebenezer Cunningham, Harry Bateman, Otto Berg, Max Planck, Max Laue, A. A. Robb, and Ludwig Silberstein, employed figures of light during the formative years of relativity theory in their discovery of the salient features of the relativistic worldview. (shrink)

A thought experiment is reviewed which shows two things. First, in a region of a rotating frame that is not simply connected, the inertial forces can be canceled without completely canceling the inertial vector potential (whose curl determines the Coriolis force); second, the presence of this uncanceled potential can be detected in a quantum interference experiment. It is then argued that the thought experiment was realized in an earlier experiment involving a rotating superconductor, and that the experimental (...) results confirm the theoretical prediction. In this way, the first experimental verification of a physical effect due to a nonelectromagnetic potential in a force-free region is established. An analogous experiment for the gravitational vector potential is also discussed. Finally, it is pointed out that the close connection between electromagnetic and inertial vector potentials provides an intuitive way to make predictions about rotating superconductors. (shrink)

A hypothesis about sensorimotor integration (the λ model) is described and applied to movement control and kinesthesia. The central idea is that the nervous system organizes positional frames of reference for the sensorimotor apparatus and produces active movements by shifting the frames in terms of spatial coordinates. Kinematic and electromyographic patterns are not programmed, but emerge from the dynamic interaction among the system s components, including external forces within the designated frame of reference. Motoneuronal threshold properties and (...) proprioceptive inputs to motoneurons may be cardinal components of the physiological mechanism that produces positional frames of reference. The hypothesis that intentional movements are produced by shifting the frame of reference is extended to multi-muscle and multi-degrees-of-freedom systems with a solution of the redundancy problem that allows the control of a joint alone or in combination with other joints to produce any desired limb configuration and movement trajectory. The model also implies that for each motor behavior, the nervous system uses a strategy that minimizes the number of changeable control variables and keeps the parameters of these changes invariant. Examples are provided of simulated kinematic and electromyographic signals from single- and multi-joint arm movements produced by suggested patterns of control variables. Empirical support is provided and additional tests of the model are suggested. The model is contrasted with others based on the ideas of programming of motoneuronal activity, muscle forces, stiffness, or movement kinematics. (shrink)

Many members of the public think of the General Medical Council (GMC) as the body which tries doctors: the doctors' law courts, as it were. And, except in the more sober of newspapers and news reports, the 'offences ' which receive the most publicity are those concerning alleged improper relations between doctors and patients. Professor Sir Denis Hill, in the following paper, which he read in the spring of this year to the annual conference of the London Medical Group devoted (...) to a discussion of human sexuality, chose to examine the whole function of the General Medical Council as a frame of moral reference for doctors. Judging allegations of professional misconduct by doctors is the function of the Council's Disciplinary Committee. Judging sexual misconduct forms only a small part of their work. The GMC's responsibility covers the whole notion of morals and morality as it concerns doctors in their professional work. Sir Denis Hill stresses the modern thinking that morality must be learned and that attitudes are always shifting as society alters its norms of what is moral conduct. That is not to say that all that was previously considered not to be moral has now become acceptable but rather that other concepts have entered the field of moral debate. Therefore the GMC must constantly review the frame of reference it offers to doctors and the public may be surprised to learn that that process is never static. Sir Denis Hill in this paper is speaking personally and not as a member of the General Medical Council or of any of that body's special committees. (shrink)

At the beginning of the year, the Draft Common Frame of Reference (DCFR) was published. The text is the result of the work of a broad range of private law scholars from the Member States of the European Union, and it presents itself as an ‘academic’ document, committed to the precepts of scholarship rather than politics. Notwithstanding its unwieldy name, the text is nothing less than the draft of the central components of a European Civil Code. The following (...) article aims to inform the reader about this potentially important document and to initiate further academic debate about it. Following an overview of the genesis and content of the DCFR (Part 1), the discussion focuses on whether, and to what extent, it is based upon consistent and convincing core aims and values (Part 2). The article then proceeds to address, more specifically, the significance of private autonomy, and it examines the extent to which the proposed rules satisfy the requirements of legal certainty and legal clarity (Part 3). Thereafter, the DCFR is measured against the criteria of internal consistency and systematic integrity (Part 4). Also (Part 5) the question is asked whether the Draft critically reflects and convincingly integrates the sources on which it is based (that is the Lando Commission's Principles of European Contract Law and the Acquis Principles, as well as the private law traditions of the Member States). Also deserving of attention is the inclusion of more than 120 definitions of central concepts of private law, which are not to be found in this form or level of detail in either the Lando Principles or the national private laws (Part 6). (shrink)

For Knox, ‘spacetime’ is to be defined functionally, as that which picks out a structure of local inertial frames. Assuming that Knox is motivated to construct this functional definition of spacetime on the grounds that it appears to identify that structure which plays theoperationalrole of spacetime—i.e., that structure which is actually surveyed by physical rods and clocks built from matter fields—we identify in this paper important limitations of her approach: these limitations are based upon the fact that there is (...) a gap between inertial frame structure and that which is operationally significant in the above sense. We present five concrete cases in which these two notions come apart, before considering various ways in which Knox’s spacetime functionalism might be amended in light of these issues. (shrink)

The Aymara of the Andes use absolute (cardinal) frames of reference for describing the relative position of ordinary objects. However, rather than encoding them in available absolute lexemes, they do it in lexemes that are intrinsic to the body: nayra (“front”) and qhipa (“back”), denoting east and west, respectively. Why? We use different but complementary ethnographic methods to investigate the nature of this encoding: (a) linguistic expressions and speech–gesture co-production, (b) linguistic patterns in the distinct regional Spanish-based variety Castellano (...) Andino (CA), (c) metaphorical extensions of CA’s spatial patterns to temporal ones, and (d) layouts of traditional houses. Findings indicate that, following fundamental principles of Aymara cosmology, people, objects, and land—as a whole—are conceived as having an implicit canonical orientation facing east, a primary landmark determined by the sunrise. The above bodily based lexicalizations are thus linguistic manifestations of a broader macro-cultural worldview and its psycho-cognitive reality. (shrink)

-discusses 3 methods of PoE instruction: PoE as foundational, Great Educators, and isms approach (p19).