250 research outputs found
Russiaâs Place in the World. Pyotr Chaadaev and the Slavophils
The purpose of this publication is to present the work by an outstanding French historian of science Alexander KoyrĂ© who was deeply interested in the Russian philosophy of history to the Russian-speaking public. The paper, written about a hundred years ago, traces the evolution of Pyotr Chaadayevâs philosophical-historical thought in the context of his polemics against Slavophiles. It was the first serious theoretical dispute about the place of Russia in world history, which largely set the pattern for subsequent disputes on this topic that continue to this day. Chaadayev wrote his Philosophical Letters in French, using the categorical apparatus of German philosophy, particularly the ideas of Schelling, with whom he was personally acquainted. Nevertheless, KoyrĂ© contests the usual characterization of Chaadayev as a refined Westernist, showing that he accepted some of Ivan Kireevskyâs and other Slavophilesâ basic statements and attitudes, including the religious ones, but interpreted them in a completely different way, after his own fashion. Chaadayev sees the reasons for the backwardness of Russian civilization in the overwhelming dominance of ascetic Christianity, on the one hand, and in the plasticity of the folk character of the Slavs, in the absence of autonomous life and ancient cultural heritage, on the other. Russian civilization belongs neither to the Eastern, closed in itself, nor to the Western expansionist type. It has its own special way of historical development. After the publication of the first Philosophical Letter in the journal Telescope in 1836, Nicholas I, by the highest decree, declared Chaadayev insane and ordered him to be placed under house arrest. The philosopher responded with Apologia of a Madman. KoyrĂ©â disputes the widespread view that Chaadayevâs historiosophic views underwent a significant change in this work, not to mention the renunciation of his sharply critical assessment of the history of Russian civilization as a kind of gap in the intellectual world order. This disadvantage, however, could turn into a springboard for a historical breakthrough towards broad welfare. In a country where the people are accustomed to blind obedience, it requires only the will of the ruler, the coming of the new Peter the Great
Had the planet mars not existed: Kepler's equant model and its physical consequences
We examine the equant model for the motion of planets, which has been the
starting point of Kepler's investigations before he modified it because of Mars
observations. We show that, up to first order in eccentricity, this model
implies for each orbit a velocity which satisfies Kepler's second law and
Hamilton's hodograph, and a centripetal acceleration with an inverse square
dependence on the distance to the sun. If this dependence is assumed to be
universal, Kepler's third law follows immediately. This elementary execice in
kinematics for undergraduates emphasizes the proximity of the equant model
coming from Ancient Greece with our present knowledge. It adds to its
historical interest a didactical relevance concerning, in particular, the
discussion of the Aristotelian or Newtonian conception of motion
Philosophy and Science in Leibniz
This paper explores the question of Leibnizâs contribution to the rise of modern âscienceâ. To be sure, it is now generally agreed that the modern category of âscienceâ did not exist in the early modern period. At the same time, this period witnessed a very important stage in the process from which modern science eventually emerged. My discussion will be aimed at uncovering the new enterprise, and the new distinctions which were taking shape in the early modern period under the banner of the old Aristotelian terminology. I will argue that Leibniz begins to theorize a distinction between physics and metaphysics that tracks our distinction between the autonomous enterprise of science in its modern meaning, and the enterprise of philosophy. I will try to show that, for Leibniz, physics proper is the study of natural phenomena in mathematical and mechanical terms without recourse for its explanations to metaphysical notions. This autonomy, however, does not imply for Leibniz that physics can say on its own all that there is to be said about the natural world. Quite the opposite. Leibniz inherits from the Aristotelian tradition the view that physics needs metaphysical roots or a metaphysical grounding. For Leibniz, what is ultimately real is reached by metaphysics, not by physics. This is, in my view, Leibnizâs chief insight: the new mathematical physics is an autonomous enterprise which offers its own kind of explanations but does not exhaust what can (and should) be said about the natural world
Movement and Fluctuations of the Vacuum
Quantum fields possess zero-point or vacuum fluctuations which induce
mechanical effects, namely generalised Casimir forces, on any scatterer.
Symmetries of vacuum therefore raise fundamental questions when confronted
with the principle of relativity of motion in vacuum. The specific case of
uniformly accelerated motion is particularly interesting, in connection with
the much debated question of the appearance of vacuum in accelerated frames.
The choice of Rindler representation, commonly used in General Relativity,
transforms vacuum fluctuations into thermal fluctuations, raising difficulties
of interpretation. In contrast, the conformal representation of uniformly
accelerated frames fits the symmetry properties of field propagation and
quantum vacuum and thus leads to extend the principle of relativity of motion
to uniform accelerations.
Mirrors moving in vacuum with a non uniform acceleration are known to
radiate. The associated radiation reaction force is directly connected to
fluctuating forces felt by motionless mirrors through fluctuation-dissipation
relations. Scatterers in vacuum undergo a quantum Brownian motion which
describes irreducible quantum fluctuations. Vacuum fluctuations impose ultimate
limitations on measurements of position in space-time, and thus challenge the
very concept of space-time localisation within a quantum framework.
For test masses greater than Planck mass, the ultimate limit in localisation
is determined by gravitational vacuum fluctuations. Not only positions in
space-time, but also geodesic distances, behave as quantum variables,
reflecting the necessary quantum nature of an underlying geometry.Comment: 17 pages, to appear in Reports on Progress in Physic
- âŠ