In the 1720s two Jesuit astronomers working at the court of King João V of Portugal, in Lisbon, received several instruments produced by the best makers in London, Paris and Rome. With the crucial help of the Portuguese diplomatic network contacts with academies, savants and instrument makers were established, seeking technical advice and the best astronomical instruments available at the time. It was in this context that in April 1726 a set of Latin instructions accompanying pendulum clocks made (...) by George Graham were dispatched from London to Lisbon. These unpublished instructions are now preserved in the papers of Giovanni Battista Carbone, one of these Jesuit astronomers, offering a significant window into the procedures and technical details involved in the setting, operation and transport of Graham’s astronomical clocks. In this paper, I will not only discuss this important document in the framework of Graham’s contributions to astronomy and horology, but also in the perspective of the search for accuracy. (shrink)

In the context of a parametric theory (with the time being a dynamical variable) we consider here the coupling between the quantum vacuum and the background gravitation that pervades the universe (unavoidable because of the universality and long range of gravity). We show that this coupling, combined with the fourth Heisenberg relation, would break the parametric invariance of the gravitational equations, introducing thus a difference between the marches of the atomic and the astronomical clocks. More precisely, they would (...) be progressively and adiabatically desynchronized with respect to one another in such a way that the latter would lag behind the former. This would produce a discrepancy between gravitational theory and observations, which use astronomical and atomic time respectively. It turns out that this result, surprising at it might be, is fully compatible with current physics, since it does not conflict with any known physical law or principle. We argue that this phenomenon must be studied, since it could have cosmological consequences. (shrink)

This paper presents an analysis of the systematic astronomical observations performed by Muḥyī al-Dīn al-Maghribī at the Maragha observatory between 1262 and 1274 AD. In a treatise entitled Talkhīṣ al-majisṭī, preserved in a unique copy at Leiden, Universiteitsbibliotheek, Muḥyī al-Dīn explains his observations and measurements of the Sun, the Moon, the superior planets, and eight reference stars. His measurements of the meridian altitudes of the Sun, the superior planets, and the eight bright stars were made using the mural quadrant (...) of the observatory, and the times of their meridian transit using a water clock. The mean absolute error in the meridian altitudes of the Sun is ~ 3.1′, of the superior planets ~ 4.6′, and of the eight fixed stars ~ 6.2′. The clepsydras used by Muḥyī al-Dīn could apparently fix time intervals with a precision of ± 5 min. His estimation of the magnitudes of three lunar eclipses observed in Maragha in 1262, 1270, and 1274 AD is in close agreement with modern data. (shrink)

ABSTRACTThe quartz clock, the first to replace the pendulum as the time standard and later a ubiquitous and highly influential technology, originated in research on means for determining frequency for the needs of telecommunication and the interests of its users. This article shows that a few groups in the US, Britain, Italy and the Netherlands developed technologies that enabled the construction of the new clock in 1927–28. To coordinate complex and large communication networks, the monopolistic American Telephone and Telegraph Company, (...) and national laboratories needed to determine and maintain a common ‘standard’ frequency measurement unit. Exploiting novel piezoelectric quartz methods and valve electronics techniques, researchers in these organizations constructed a new crystal-based frequency standard. To ensure its accuracy they compared it to an accepted absolute standard - an astronomical clock, constructing thereby the first quartz clock. Other groups, however, had different, though connected, technological aims, which originated from the diverse interests of the industrial, governmental and academic institutes to which they belonged, and for which they needed to measure, control and manipulate with frequencies of electric oscillations. The present article suggests a comparative examination of the research and development paths of these groups on their incentives, the technological and scientific resources they utilized, and the kind of research carried out in the various institutional settings. (shrink)

The Libros del Saber de Astronomia is a compilation of various Arabic astronomical works translated into Castilian in the second half of the thirteenth century, under the direction of King Alfonso X of Spain. A section describing a mercury clock has been suggested to be of particular significance in view of the likely invention of the mechanical clock around this period, so a new translation into modern technical English has been prepared. The clock is shown to consist essentially of (...) an annulus of mercury-filled chambers separated by narrow partitions, each partition being perforated by a very small hole. This annulus is attached concentrically to a pulley wheel around which a cord is wrapped, and a fixed weight hung upon the cord. The torque raises the mercury on the opposite side, but as the resulting hydrostatic head then causes it to percolate through the holes connecting the chambers the wheel slowly rotates to maintain its equilibrium. The weight therefore gradually descends in a controlled manner. It is claimed that, by suitable adjustment of the driving weight, the wheel could be made to turn once in 4 hours. A 6:1 reduction gear therefore enabled the rete of an astrolabe to be rotated once in 24 hours, modelling the real sky so that the time could be read off directly against the plate.A working model has been constructed on these principles, but utilizing modern materials to contain the mercury. It does work, but the range of rotation periods is quite limited and the reproducibility poor . It is shown that this is a consequence of the compounding of errors in what amounts to a ring of ‘mercury glasses’ joined end-to-end, for a single ‘mercury glass’ has a standard deviation of ±1.7 per cent and five or six are in use at any one time. Errors and omissions in the Castilian account suggest that the translator had never seen the instrument they attempt to describe.The mercury clock of the Libros is not isochronous, and its constant unidirectional rotation contrasts with the oscillators that are the hallmark of all advanced timekeepers. It is concluded that, although an interesting experiment, it had no influence on the evolution of clockwork in the western world. (shrink)

SummaryThis paper discusses how the notion of clock time was introduced in the Greek world. On the basis of an analysis of the earliest (potential) references to hours and clocks in texts from the late fifth to the early third century BC in their historical context, and with reference to the earliest archaeologically attested clocks, it proposes a scenario for the conception and development of this conventional system. It offers a new interpretation of the problematic passage Herodotus 2.109 (...) and argues that an hour-like unit was developed by late fifth century astronomers, under Babylonian influence, to denote the time in which a celestial body moves through a section of its diurnal circle. When this astronomical concept moved to the civic sphere in the second half of the fourth century, it changed from a scientific unit of duration to a civic unit for measuring the time of day. This shift probably took place in Athens, where the first references to hours appear in this period together with multiple experiments in clock making, as well as humorous reactions to the newfound sense of temporal precision. The paper will also show, however, that these first clocks did not yet tell seasonal hours – the type of hours that would eventually define Greco-Roman clock time – and still measured the lapse of time rather than enabling the location of moments in time. Greco-Roman clock time was only fully formed when it incorporated Egyptian notions of the hour in the Ptolemaic kingdom of the early third century BC. (shrink)

The San Zeno Wheel of Verona is an exceptional, virtually unstudied fifteenth-century horological device, the only one of its type to have survived. Yet certain features of the Wheel correspond to contemporary manuscript volvelles and to the liturgical calendars of larger horological devices. The interpretation of the object presented here has two main objectives: first, to elucidate the Wheel itself; and second, to consider its role in relation to the ecclesiastical routines of the San Zeno complex. By investigating the relationship (...) of the Wheel to fourteenth- and fifteenth-century time-reckoning instruments, notably astronomical clocks, the article shows that it is the oldest liturgical calendar disk to survive and, therefore, an invaluable testament to the original appearance of the earliest astronomical clocks. This is followed by a reconstruction of the way in which the Wheel was used in its original setting. An interpretation of its content in relation to the other horologia at San Zeno suggests that it was made to complement another time-reckoning device in the basilica. San Zeno therefore provides a unique case study regarding the ways in which multiple time systems were synchronised in the reckoning of the liturgy following the invention of the mechanical clock. The analysis of the Wheel has potentially far-reaching implications for our understanding of the ways in which the dispensation of mechanical horologia in monastic settings affected the perception of time. Such an analysis is, therefore, significant not only for the study of historical horology, but of medieval temporality more generally. (shrink)

As Astronomer Royal from 1835 till 1881, G. B. Airy had a very important influence on nineteenth-century British astronomy. His personal qualities combined with his office to give him a position of great authority within the astronomical and general scientific communities, and his powers of organization and work on instrumentation transformed the Royal Observatory. A feature of Airy's work was an extensive interest in horology—particularly in astronomical regulators, marine chronometers and driving clocks for chronographs and equatorial telescopes. (...) He was also concerned with building important turret clocks, and he established a public time service based at Greenwich. The enormous quantity of surviving material makes a complete review of Airy's career a daunting prospect; but the horology is a microcosm, where we can study on a manageable scale his attitudes to the Observatory, to its relation to society, and to the role of the Astronomer Royal as a public servant. (shrink)

Introduction Jamie Allen Time, of all the dimensions readily presented to experience, seems to do so most readily through things. Stuff, in supposed counter-valence to the negentropic resilience of living things, appears to us as that which degrades through time, and demarcates a more technical chronometry of sequential events. Situated outside the rotting of fruit and the ticking of clocks, a “deep time” persists. Like the ultra-hearing of the bat, and the infra-vision of the boa-constrictor, there exist living and (...) non-living agents and entities capable of revealing the fixity and finitude of our own perceptual frames for thinking and understanding. The recordings presented here consist of four extracts of documents made in deep geological repository sites (for the storage of nuclear waste). Here re-presented are the Yucca Mountain Repository; HADES, in Mol, Belgium; Gorleben in Germany and a further recording from Forsmark in Sweden (pretty much inaudible behind a loop of a pop song). These recordings are imagined acoustic amplifications of deep time, just as the astronomer’s telescope is (thought of a certain way), also a time machine. Stars and nuclear waste are unapparent objects of temporal thought. Andy Weir is an artist from London researching effects of deprioritised subjectivity and contemporary art. This project draws on work developing sonic fictions, stealthy earworms, and micropolitical agencies. Prompted for further thoughts about the recordings presented here, he offered up the interspersed discussion included. —JA Yucca Mountain Repository, Nevada, USA by continent I became interested in these sites originally as spaces that allude to a time outside of the human (‘deep time’) as they are designed to store waste ‘without future maintenance’. The very fact of thinking about these spaces or working on them—engineering etc.. (as I’m particularly interested them in a kind of practice rather than just an object of thought), in other words, forces a confrontation with thought of the extinction of humanity. I was interested in this as a production of affect at odds with the expected ‘ironic, can be whatever you like’ interpretive condition of contemporary art (art under the condition of neoliberalism, say, where the individual subject is prioritised as a free autonomous producer of the meaning of the work) When I thought about this a bit though it ran into paradoxes—yes, I could allude to deep time, but in doing so I just allude to its un-representability, drawing attention to the limits of representation and so reaffirming it—I was stuck in a representation/non-representational negative dialectic. In trying to somehow create a figure for deep time I was either reducing it to my description of it, or presenting it as irreducible. HADES Facility, Mol, Belgium by continent I don’t think I’ve escaped this in the work but my response to it was to create a sonic-fiction. This was based on the idea of a viral transmission of the affect of deep time (this is the ‘pyroclastic-soaked chrono-dread’) through receiving apparatuses, transforming the screen into an intercessor or mediating lure for the outside, a site of exposure multiplying virulently through its dissemination, invoking as much as trying to represent these spaces, the sounds as durations of exposure to contagious materials, and fictions as a way of excavating the strangeness of a world opaque to subjective reconfiguration... Testing out I suppose ways that art could start thinking about figuring the reality of ecological crisis. Gorleben Repository, Lower Saxony, Germany by continent While everything remains at the level of fiction I think the work is problematic. It doesn’t really model anything, giving too much authority to either romantic abandonment or the recuperation of romantic abandonment under its description by theory/philosophy, all contained and controlled by me within a fairly limited condition of what art can do. Deep Time Contagion is precisely a materialisation of and transmission of this paradox (i.e. with screen-media can only present deep time as unrepresentable or draw attention to an inability to present it) taking the comfort/panic induced by this paradox as its material. I’m working now on some new projects that take this as a point of departure. Forsmark Repository, Sweden (Robitussin Mix) by continent. (shrink)

The 'Reaction experiment with Hipp chronoscope' is one of the classical experiments of modern psychology. This paper investigates the technological contexts of this experiment. It argues that the development of time measurement and communication in other areas of science and technology (astronomy, the clock industry) were decisive for shaping the material culture of experimental in psychology. The chronoscope was constructed by Matthaus Hipp (1813-1893) in the late 1840s. In 1861, Adolphe Hirsch (1830-1901) introduced the chronoscope for measuring the 'physiological time' (...) of astronomical observers. Hirsch's observatory at Neuchatel (Switzerland) served to control the quality of clocks produced in the nearby Jura mountains. Hipp provided the observatory with a telegraphic system that sent time signals to the centers of clock production. Time telegraphy constituted the stable surroundings of the reaction time experiments carried out by both astronomers and psychologists. This technology permitted precise measurements of short time intervals and offered to Hirsch, as well as to Wilhelm Wundt (1832-1920), a useful metaphor for conceptualizing their respective 'epistemic objects'. But time telegraphy also limited the possibilities of the experimental work conducted within its framework. In particular, noise from outside and inside the research sites at Neuchatel, Leipzig and elsewhere disturbed the precise communication of time. (shrink)

Pt. I. The velocity of light. Mersenne's measurement of the speed of sound -- Galileo's attempt to measure the velocity of light -- Roemer's astronomical method -- Bradley's telescope method -- Fizeau's terrestrial method -- Michelson's precise measurement -- Other properties of light waves -- pt. II. The great dilemma. The stationary ether postulated -- Further confirmation of the ether -- An expected ether effect -- Fresnel's ether drag -- The Michelson-Morely experiment -- Possible explanations for Michelson and Morley's (...) results -- The great dilemma -- pt. III. The special theory of relativity. Difference between the special theory and the general theory -- The two postulates of the special theory -- Deductions from the postulates -- Contraction of length -- Mass increases with velocity -- Addition of velocities -- The maximum possible velocity -- Equivalence of mass and energy -- Time in the special theory -- pt. IV. Experimental proof of the special theory. Mass increase with velocity -- Addition of velocities -- Equivalence of mass and energy -- Time -- pt. V. The general theory and experimental proof. The principle of equivalence -- Newton's law of universal gravitation and Einstein's theory of gravitation / Rotation of Mercury's orbit -- Effect of a gravitational mass on a light beam / Weighing a beam of light -- Effect of a gravitational mass on time / Slowing down of atomic clocks on the sun and stars -- pt. VI. Relativity and the nature of the universe. Types of universes -- Our universe -- pt. VII. The unified field theory. (shrink)

I argue that “time” (χρόνος) in Plato’s Timaeus is the observable astronomical event that consists of the coordinated movements of the sun, the moon, the five observable planets and the earth. This celestial parade forms a unified event that imitates eternity through the uniformity of its movements, its unity in multiplicity, and its never-ending duration (sempiternity a parte post). Therefore, it is a mistake to conceive of time in Timaeus as a celestial clock, the type of movements involved in (...) the celestial parade, an epiphenomenon of those movements, simple duration, absolute time, an intuition, a number or any other formal or metaphysical entity. (shrink)

SummaryThis paper explores how nineteenth-century Liverpool became such an advanced city with regard to public timekeeping, and the wider impact of this on the standardisation of time. From the mid-1840s, local scientists and municipal bodies in the port city were engaged in improving the ways in which accurate time was communicated to ships and the general public. As a result, Liverpool was the first British city to witness the formation of a synchronised clock system, based on an invention by Robert (...) Jones. His method gained a considerable reputation in the scientific and engineering communities, which led to its subsequent replication at a number of astronomical observatories such as Greenwich and Edinburgh. As a further key example of developments in time-signalling techniques, this paper also focuses on the time ball established in Liverpool by the Electric Telegraph Company in collaboration with George Biddell Airy, the Astronomer Royal. This is a particularly significant development because, as the present paper illustrates, one of the most important technologies in measuring the accuracy of the Greenwich time signal took shape in the experimental operation of the time ball. The inventions and knowledge which emerged from the context of Liverpool were vital to the transformation of public timekeeping in Victorian Britain. (shrink)

Previous research has reported that ethical values of business students are lower than those of their peers in other majors. The purpose of this study was to investigate whether a self-selection bias with respect to ethical values exists among students enrolled as business majors when compared with students planning to enter the engineering profession. Engineering students are exposed to a similar technical orientation in academic curricula and also supply the market for managers.A survey instrument was administered to 195 students enrolled (...) in undergraduate business and engineering programs and a graduate business program. The research instrument measured how business and engineering students perceive their own ethical beliefs and actions and how they perceived the ethical beliefs and actions of their peers. (shrink)

Hard direction, e.g.: Universalese to Organicese. Suggestion: ‘Some chairs wobble’ should become something like ‘If composition were universal, some chairs wobble’ or ‘Assuming that composition is universal, some chairs wobble’ or ‘According to the fiction that composition is universal, some chairs wobble’.

O artigo traz resultados de uma investigação de mestrado que teve por objetivo pesquisar as concepções de um grupo de professores a respeito das funções que os mesmos exercem frente à sociedade contemporânea. Partiu-se da premissa de que suas concepções guardam relação com suas práticas educativas e pedagógicas. Trata-se de uma pesquisa desenvolvida na perspectiva qualitativa, com cinquenta e um professores que atuam em seis escolas estaduais da cidade de Ponta Grossa-PR. Elegeu-se como aporte teórico autores que tratam da formação (...) de professores e da profissão docente, como Freire, Imbernón, Ens e Behrens, Tozetto, Sacristán e Tedesco. Os dados foram coletados por meio de questionários, categorizados e analisados seguindo os pressupostos na Análise de Conteúdo. Três categorias foram configuradas a partir de significantes presentes nas respostas dos professores participantes: Categoria I – Professor como um sujeito transformador: educação em uma forma ampla, Categoria II – Professor como profissional do conhecimento, e Categoria III – Professor enquanto sujeito que desempenha vários papéis sociais. Essas categorias nos possibilitaram inferir que as concepções dos professores em relação ao seu papel na sociedade contemporânea vão além da função social da escola, pois centram-se primeiramente na figura de um profissional transformador do mundo; seguida da noção de profissional do conhecimento e, por fim, da ideia de um profissional que desempenha vários papéis sociais. A pesquisa também apontou uma necessária redefinição da profissão docente para que os professores assumam novas competências profissionais na contemporaneidade. Palavras-chave: Profissão docente. Função dos professores. Sociedade contemporânea. Concepções. (shrink)

The clock hypothesis of relativity theory equates the proper time experienced by a point particle along a timelike curve with the length of that curve as determined by the metric. Is it possible to prove that particular types of clocks satisfy the clock hypothesis, thus genuinely measure proper time, at least approximately? Because most real clocks would be enormously complicated to study in this connection, focusing attention on an idealized light clock is attractive. The present paper extends and (...) generalized partial results along these lines with a theorem showing that, for any timelike curve in any spacetime, there is a light clock that measures the curve’s length as accurately and regularly as one wishes. (shrink)

This paper aims at tracking down, by looking at late medieval and early modern discussions over the ontological status of artifacts, the main steps of the process through which nature became theorized on a mechanistic model in the early 17th century. The adopted methodology consists in examining how inventions such as mechanical clocks and automata forced philosophers to modify traditional criteria based on an intrinsic principle of motion and rest for defining natural beings. The paper studies different strategies designed (...) in the transitional period 1300–1600 for making these inventions compatible with classical definitions of nature and artifacts. In the first part of the paper, it is shown that, even if virtually all medieval philosophers acknowledged an ontological distinction between artifacts and natural beings, these different strategies demonstrate a growing concern about the consistency of the art/nature distinction. The next part of the paper studies how mechanical clocks, even before the Scientific Revolution, served as theoretical models for applying mechanistic views to different objects (be they cosmological, physical or biological). The epistemological function of clocks appears to stem from different factors (like the specific manufacturing of late medieval clocks as well as the evolution of 16th-century mechanics) that are listed in this second part of the paper. These factors, combined with the definitional issues raised by automata, explain that clocks became the symbol of a new approach to natural philosophy, characterized by the collapse of the art/nature distinction and the “mechanization of nature”. (shrink)

Cellular circadian clocks represent ancient anticipatory systems which co‐evolved with the first cells to safeguard their survival. Cyanobacteria represent one of the most ancient cells, having essentially invented photosynthesis together with redox‐based cellular circadian clocks some 2.7 billion years ago. Bioelectricity phenomena, based on redox homeostasis associated electron transfers in membranes and within protein complexes inserted in excitable membranes, play important roles, not only in the cellular circadian clocks and in anesthetics‐sensitive cellular sentience (awareness of environment), but (...) also in the coupling of single cells into tissues and organs of unitary multicellular organisms. This integration of cellular circadian clocks with cellular basis of sentience is an essential feature of the cognitive CBC‐Clock basis of cellular life. (shrink)

Circalunar clocks, which allow organisms to time reproduction to lunar phase, have been experimentally proven but are still not understood at the molecular level. Currently, a new generation of researchers with new tools is setting out to fill this gap. Our essay provides an overview of classic experiments on circalunar clocks. From the unpublished work of the late D. Neumann we also present a novel phase response curve for a circalunar clock. These experiments highlight avenues for molecular work (...) and call for rigor in setting up and analyzing the logistically complex experiments on circalunar clocks. Re‐evaluating classic experiments, we propose that (1) circalunar clocks in different organisms will have divergent mechanisms and physiological bases, (2) they may have properties very different from the well‐studied circadian clocks and (3) they may have close mechanistic and molecular relations to seasonal rhythms and diapause. (shrink)

Recent work in the physics literature demonstrates that, in particular classes of rotating spacetimes, physical light rays in general do not traverse null geodesics. Having presented this result, we discuss its philosophical significance, both for the clock hypothesis (and, in particular, a recent purported proof thereof for light clocks), and for the operational meaning of the metric field. 1. Introduction2. Fletcher's Theorem2.1. Maudlin on the clock hypothesis in special relativity2.2. Fletcher’s result in special relativity2.3. Fletcher’s theorem in general relativity3. (...) Electromagnetism and the Geometrical-Optical Limit 3.1. Maxwell’s equations in curved spacetime3.2. The geometrical-optical limit3.3. Rotating spacetimes3.4. Aren’t Gödel spacetimes unphysical?4. The Clock Hypothesis and Chronogeometry 4.1. Natural and mathematical observations4.2. Clock registry discord4.3. Chronogeometry5. Conclusion. (shrink)

Sound propagation within certain non-relativistic condensed matter models obeys a relativistic wave equation despite such systems admitting entirely non-relativistic descriptions. A natural question that arises upon consideration of this is, “do devices exist that will experience the relativity in these systems?” We describe a thought experiment in which ‘acoustic observers’ possess devices called sound clocks that can be connected to form chains. Careful investigation shows that appropriately constructed chains of stationary and moving sound clocks are perceived by observers (...) on the other chain as undergoing the relativistic phenomena of length contraction and time dilation by the Lorentz factor, \, with \ the speed of sound. Sound clocks within moving chains actually tick less frequently than stationary ones and must be separated by a shorter distance than when stationary to satisfy simultaneity conditions. Stationary sound clocks appear to be length contracted and time dilated to moving observers due to their misunderstanding of their own state of motion with respect to the laboratory. Observers restricted to using sound clocks describe a universe kinematically consistent with the theory of special relativity, despite the preferred frame of their universe in the laboratory. Such devices show promise in further probing analogue relativity models, for example in investigating phenomena that require careful consideration of the proper time elapsed for observers. (shrink)

A passenger boards a fast train. It takes her some distance, makes a u-turn, and returns to the starting platform. She reports that according to her clock, the trip took n seconds. An observer on the platform, using his own clock, gets a different reading. He records a longer time interval m. These claims are compatible with the clocks being in perfect order. Modern Physics tells us that time is a relativistic notion. The duration of the trip, understood as (...) the temporal distance between the departure and the return event, will depend on the chosen frame of reference. The passenger and the observer belong to different frames. This is the source of the discrepancy. Suppose that the passenger and the observer speak a language that is like ours with possible differences arising from the assumption that no one in their community knows about modern physics. Let us call this language '19th Century English'. Imagine that the agents, in different conversations, utter sentences (1) and (2) respectively. (shrink)

Daylight is the primary cue used by circadian clocks to entrain to the day/night cycle so as to synchronize physiological processes with periodic environmental changes induced by Earth rotation.However, the temporal daylight pattern is not the same every day due to erratic weather fluctuations or regular seasonal changes. Then, how do circadian clocks operate properly in varying weather and seasons? In this paper, we discuss the strategy unveiled by recent studies of the circadian clock of Ostreococcus tauri, the (...) smallest free‐living eukaryotic organism. It combines mechanisms controlling light inputs and clock sensitivity, shaping both the dynamics of the core circadian oscillator and its forcing by light so as to ensure stable and precise synchronization in all weather and seasons.Editor's suggested further reading in BioEssays: Another place, another timer: Marine species and the rhythms of life Abstract. (shrink)

Across a wide range of cultural forms, including philosophy, cultural theory, literature and art, the figure of the clock has drawn suspicion, censure and outright hostility. In contrast, even while maps have been shown to be complicit with forms of domination, they are also widely recognised as tools that can be critically reworked in the service of more liberatory ends. This paper seeks to counteract the tendency to see clocks in this way, arguing that they have many more interesting (...) possibilities than they are usually given credit for. An analysis of approaches to clocks in continental philosophy critiques the way they have too often been dismissed as unworthy of further analysis, and argues that this dismissal is based upon an inadequate understanding of how clocks operate. Seeking to move towards more critical and curious approaches, the paper draws inspiration from critical cartography in order to call for the development of a ‘critical horology’ which would emphasise both the fundamentally political nature of clocks, and the potential for designing them otherwise. A discussion of temporal design provides a range of examples of how clocks might open up new horizons within the politics of time. (shrink)

The ArgumentIt is often assumed that all sciences travel the path of increasing precision and quantification. It is also assumed that such processes transcend the boundaries of rival scientific disciplines. The history of the personal equation has been cited as an example: the “personal equation” was the name given by astronomers after Bessel to the differences in measured transit times recorded by observers in the same situation. Later in the nineteenth century Wilhelm Wundt used this phenomenon as a type for (...) his experiments on reaction times. For historians of psychology, this has been taken to be an exemplary case where quantified laboratory science rescued astronomy by showing that this was really a psychological phenomenon measurable only in complication experiments. This paper challenges this story. Astronomers neither ignored, nor despaired of, the personality problem. Instead, the managers of the great observatories developed a new chronometric regime of vigilant surveillance of subordinate observers. The astronomers' solution was thus intimately connected with social and material changes in their way of life: a division of labor in the observatories, a network of observing sites, a mechanization of observation. The paper documents these changes and then presents a study of one case where managers, amateurs, and psychologists clashed for authority over the personality problem. Measurement is given its meaning when situated in specific contexts of styles of work and institutions. Disciplines give meanings to values, and often resist attempts by others to redefine these meanings or to gain authority over measurement. Quantification is not a self-evident nor inevitable process in science's history, but possesses a remarkable cultural history of its own. (shrink)

This paper (i) gives necessary and sufficient conditions that clocks in an inertial lattice can be synchronized, (ii) shows that these conditions do not imply a universal light speed, and (iii) shows that the terrestrial redshift experiment provides evidence that clocks in a small inertial lattice in a gravitational field can be synchronized.

Scientists, both modern and contemporary, commonly try to discern patterns in nature. They also frequently use arguments by analogy to construct an understanding of the natural mechanisms responsible for producing such patterns. For Robert Boyle, the famous clock at Strasbourg provided a perfect paradigm for understanding the connection between these two scientific activities. Unfortunately, it also posed a serious threat to his realistic pretensions. All sorts of internal mechanisms could produce precisely the same movements across the face of a clock. (...) Given God's immense creative capacities, Boyle realized that standard epistemological constraints could never ensure, not even to the least degree of probability, that scientific theories about the unobservable mechanisms of nature were descriptively accurate. Like most moderns, he fortified his epistemology theologically in order to retain his realistic stance. John Locke, however, took counsel from Ecclesiastes to repudiate Boyle's realism, while Samuel Clarke mobilized biblical images to dismiss the clockwork paradigm altogether.A contemporary review of this modern controversy reveals that there is still much to learn from the clock at Strasbourg. Among other things, the realism/antirealism issue is of central importance to understanding today's science, Nancey Murphy's protests notwithstanding. Moreover, the kind of realistic stance that is essential, not only to the truth but to the very intelligibility of certain types of scientific explanation, demands more than the critical realism of Ian Barbour. To be taken seriously, the models used in such contexts must be taken literally. (shrink)

A clock can do two things: it can give the time, and it can measure time. Perhaps the first function is the more humanly important. But one might say that a clock can only give the time by measuring time; at some point it is ‘fed’ the time, or the date, and if it subsequently keeps good time—measures time accurately—one can use it to read off later times or dates.

Somites are transient structures which represent the most overt segmental feature of the vertebrate embryo. The strict temporal regulation of somitogenesis is of critical developmental importance since many segmental structures adopt a periodicity based on that of the somites. Until recently, the mechanisms underlying the periodicity of somitogenesis were largely unknown. Based on the oscillations of c-hairy1 and lunatic fringe RNA, we now have evidence for an intrinsic segmentation clock in presomitic cells. Translation of this temporal periodicity into a spatial (...) periodicity, through somite formation, requires Notch signaling. While the Hox genes are certainly involved, it remains unknown how the metameric vertebrate axis becomes regionalized along the antero–posterior (AP) dimension into the occipital, cervical, thoracic, lumbar, and sacral domains. We discuss the implications of cell division as a clock mechanism underlying the regionalization of somites and their derivatives along the AP axis. Possible links between the segmentation clock and axial regionalization are also discussed. (shrink)

On receiver-based teleosemantic theories of representation, the chemical states of the circadian clocks in animal, plant and cyanobacterial cells constitute signals of future states of affairs, often the rising and setting of the sun. This signalling is much more rigid than sophisticated representational systems like human language, but it is not simple on all dimensions. In most organisms the clock regulates many different circadian rhythms. The process of entrainment ensures that the mapping between chemical states of the clock and (...) the daily light-dark cycle is adjusted to deal with seasonal changes. In regulating anticipatory behaviour, the states of the clock look forward both to the time the behaviour is supposed to happen and the later time when the anticipated circumstances are supposed to arise. The case of the circadian clock shows that purely indicative signals can arise in very basic biological systems and brings into sharp relief the trade-offs involved in characterizing representational systems. On receiver-based teleosemantic theories, future-directed signals are not restricted to complex multicellular organisms but are ubiquitous in the biological world. (shrink)

When addressing the notion of proper time in the theory of relativity, it is usually taken for granted that the time read by an accelerated clock is given by the Minkowski proper time. However, there are authors like Harvey Brown that consider necessary an extra assumption to arrive at this result, the so-called clock hypothesis. In opposition to Brown, Richard TW Arthur takes the clock hypothesis to be already implicit in the theory. In this paper I will present a view (...) different from these authors by taking into account Einstein’s notion of natural clock and showing its relevance to the debate. (shrink)

In this dissertation I examine how the English philosopher-theologian Samuel Clarke (1675--1729) attempted to reasonableness of Christianity and its compatibility with the new natural philosophy. In reaction to what he perceived as the problematic excesses of mechanical philosophy, with its looming threat of atheism, Clarke developed a series of arguments against atheism which aimed to show the shortcomings of a purely material or mechanical explanation of the universe, and demonstrate the overall `reasonability' of the Christian religion. Clarke aimed to demonstrate (...) the `reasonableness' of Christianity by turning the `mathematical' style of reasoning of the mechanical philosophy against his atheist adversaries. Clarke's writings offer us a valuable case-study for the complex interplay of philosophy, science and religion in England at the start of the eighteenth century, and the impact of mechanical philosophy on natural theology. This dissertation aims to improve our understanding of Clarke's philosophy through careful examination of its principal components: The active role of God in the world, the perfection of God's plan, the existence of immaterial substances and powers, and the subsequent reasonability of the Christian religion. Taken together, the four chapters show Clarke's solutions to the atheist threats, and provide a coherent picture of Clarke's ideas about the nature of God and God's role in the world. (shrink)

Einstein’s equivalence principle has a number of problems, and it is often applied incorrectly. Clocks on the earth do not seem to be affected by the sun’s gravitational potential. The most commonly accepted reason given is a faulty application of the equivalence principle. While no valid reason is available within either the special or general theories of relativity, ether theories can provide a valid explanation. A clock bias of the correct magnitude and position dependence can convert the Selleri transformation (...) of ether theories into an apparent Lorentz transformation, which gives rise to an apparent equivalence of inertial frames. The results indicate that the special theory is invalid and that only an apparent relativity exists. (shrink)

Abstract:This article examines the use of astronomical chronology in Jesuit and secular works of history between the mid-seventeenth and mid-eighteenth centuries. It suggests that the highly visible adoption of astronomical records in historical scholarship in Enlightenment Europe by Nicolas Fréret and Voltaire was entangled with debates about Chinese chronology, translated by Jesuit missionaries. The article argues that the missionary Martino Martini's experience of the Manchu conquest of China was crucial in shaping his conception of history as a discipline. (...) Political events that unfolded in seventeenth-century China had a marked effect on discussions about emergent world history in eighteenth-century Europe. (shrink)

In the eighteenth century, the sciences and their applications adopted a new attitude based on quantification and, increasingly, on a notion of precision. Within this process, instruments played a significant role. However, while new devices such as the micrometer, telescope, and pendulum clock embodied a formerly unknown potential of precision, this could only be realized by defining a set of practices regulating their application and control. The paper picks up the case of pendulum clocks used in eighteenth-century observatories in (...) order to show the process of learning in the course of which the pendulum clock first became a precision instrument. By examining the results of an especially developed statistical analysis, conducted to compare the performance of eighteenth-century clocks, it highlights the diversity of conditions, attitudes, and manners of handling that are characteristic for the epoch. In this way, it underlines the necessity of standardization of timekeeping practices rather than exclusively focusing on the technological development of clocks. Ultimately, the paper discusses the role of makers and users in order to show the evolution of a “precision instrument.”. (shrink)

A core principle of modern science holds that a scientific explanation must not attribute will or agency to natural phenomena.The Restless Clock examines the origins and history of this, in particular as it applies to the science of living things. This is also the story of a tradition of radicals—dissenters who embraced the opposite view, that agency is an essential and ineradicable part of nature. Beginning with the church and courtly automata of early modern Europe, Jessica Riskin guides us through (...) our thinking about the extent to which animals might be understood as mere machines. We encounter fantastic robots and cyborgs as well as a cast of scientific and philosophical luminaries, including Descartes and Leibnitz, Lamarck and Darwin, whose ideas gain new relevance in Riskin's hands. The book ends with a riveting discussion of how the dialectic continues in genetics, epigenetics, and evolutionary biology, where work continues to naturalize different forms of agency.The Restless Clock reveals the deeply buried roots of current debates in artificial intelligence, cognitive science, and evolutionary biology. (shrink)

We present Backward Clock, an original counterexample to Robert Nozick’s truth-tracking analysis of propositional knowledge, which works differently from other putative counterexamples and avoids objections to which they are vulnerable. We then argue that four ways of analysing knowledge in terms of safety, including Duncan Pritchard’s, cannot withstand Backward Clock either.

This paper surveys the results established so far by the on-going research on the planetary theories in Arabic astronomy. The most important results of the Maragha astronomers are gathered here for the first time, and new areas for future research are delineated. The conclusions reached demonstrate that the Arabic astronomical works mentioned here not only elaborate the connection between Arabic astronomy and Copernicus, but also that such activities, namely the continuous reformulation of Greek astronomy, were not limited to a (...) specific group of astronomers or to a specific geographical area. It is shown that such activities were spread over a period of more than seven hundred years, from the early eleventh till the sixteenth century, and over an area stretching from the Andalusian peninsula in the west to the farthest reaches of Central Asia in the east. (shrink)

ArgumentTextual and material evidence suggests that early Byzantine architects, known asmechanikoi, were comprehensively educated in the mathematical sciences according to contemporary standards. This paper explores the significance of the astronomical and optical sciences for the working methods of the twomechanikoiof Hagia Sophia in Constantinople, Anthemios of Tralles and Isidoros of Miletus. It argues that one major concern in the sixth-century architectural design of the Great Church was the visual effect of its sacred interior, particularly the luminosity within. Anthemios and (...) Isidoros seem to have been thoroughly conversant with the ancient corpus of astronomical and optical writings and, as will be shown, implemented their theoretical knowledge in the design of Hagia Sophia. Specifically, the paper demonstrates that the orientation of the building's longitudinal axis coincides with the sunrise on the winter solstice according to ancient computations, implying that the orientation was intentionally calculated in order to secure an advantageous natural illumination of the interior. Light and visual effects served to reinforce the symbolic significance of the sacred space that furthermore provides evidence for optical considerations with respect to late antique concepts of light and vision. (shrink)

A reanalysis of the eight astronomical images that Johann Adam Schall von Bell incorporated in the first Chinese treatise on the telescope to illustrate the telescopic discoveries made by Galileo Galilei shows that they were borrowed from the works on telescopic astronomy by Galileo Galilei and Johann Georg Locher, a student of Christopher Scheiner. Except minor changes to both Galileo’s illustrations of the telescopic view of the moon and nebulae and Locher’s illustration of sunspots, Locher’s images about the phases (...) of Venus and Jovian satellites were redrawn presumably to convey a clearer commitment to Tycho Brahe’s system of the world and most of the contents in Locher’s image of Saturn was replaced by Schall’s own observation. These changes seem to be the result of two important factors that confined the transcultural transmission of astronomical knowledge from Europe to China through the Jesuits in the seventeenth century, namely the official standpoint of the Catholic Church on the ongoing cosmological issues and the cultural tradition of Chinese astronomy. (shrink)