What remains of probability?

This paper offers some reflections on the concepts of objective and subjective probability and Lewis' Principal Principle

How to move an electromagnetic field?

As a first principle, it is the basic assumption of the standard relativistic formulation of classical electrodynamics (ED) that the physical laws describing the electromagnetic phenomena satisfy the relativity principle (RP). According to the standard view, this assumption is absolutely unproblematic, and its correctness is well confirmed, at least in a hypothetico-deductive sense, by means of the empirical confirmation of the consequences derived from it. In this paper, we will challenge this customary view as being somewhat simplistic. The RP is actually used in exceptional cases satisfying some special conditions. As we will see, however, it is quite problematic how the RP must be understood in the general case of a coupled particles + electromagnetic field system

On the formal statement of the special principle of relativity

The aim of the paper is to develop a proper mathematical formalism which can help to clarify the necessary conceptual plugins to the special principle of relativity and leads to a deeper understanding of the principle in its widest generality

Is the relativity principle consistent with classical electrodynamics? Towards a logico-empiricist reconstruction of a physical theory

The transformation rules for the basic electrodynamical quantities are routinely derived from the hypothesis that the relativity principle (RP) applies for Maxwell's electrodynamics. These derivations leave open several questions: (1) Is the RP a true law of nature for electrodynamical phenomena? (2) Are, at least, the transformation rules of the fundamental electrodynamical quantities, derived from the RP, true? (3) Is the RP consistent with the laws of electrodynamics in one single inertial frame of reference? (4) Are, at least, the derived transformation rules consistent with the laws of electrodynamics in one single frame of reference? (1) and (2) are empirical questions; we will investigate problems (3) and (4). First we will develop a formalism of the RP. In the second part, we will deal with the operational definitions of the fundamental quantities. In the third part of the paper we will show that the proper transformation rules are indeed identical with the ones obtained by presuming the covariance, and that the covariance is indeed satisfied. Problem (3) raises conceptual problems to which there seems no satisfactory solution in electrodynamics; thus, contrary to the widespread views, the question we asked in the title has no obvious answer.Comment: 39 pages, 3 figures, LaTeX; more concise notations, elucidatory remarks and examples adde

Potential links between rural tourism and agriculture in the Northern Great Plain Region

Agriculture has played and still plays a significant role in the life of rural communities and in rural development. But, because agriculture yields low revenues, agricultural workers often need a source of additional income. Agriculture combines excellently with the growing of medicinal herbs, organic farming, handicrafts and tourism. Rural tourism, as originally conceived, is a source of revenue to supplement income from agriculture. In Hungary, however, the ties between these two activities are very weak. Our current research is focused on assessing the willingness of land owners and agricultural entrepreneurs in the Northern Great Plain region to engage in rural tourism, as well as the willingness of rural hosts to start agricultural activities. Additionally, we seek to assess the potential opportunities for combining agricultural activities and rural tourism in the region by identifying the factors behind the successful operation of profitable enterprises pursuing both lines of business. We also look at the potential economic results from these two activities, and how they might change the revenue levels of the region’s dwellers. We have administered our questionnaire to 122 enterprises so far. ------------------------------------ A mezÅ‘gazdaság a vidéki területek életében, a vidékfejlesztésben jelentÅ‘s funkciókat töltött és tölt be ma is. A mezÅ‘gazdaság alacsony jövedelemtermelÅ‘ képessége kapcsán azonban szükségessé válhat a mezÅ‘gazdaságban dolgozók jövedelmének kiegészítése. A tevékenységhez kitűnÅ‘en kapcsolható a gyógynövénytermesztés, biogazdálkodás, kézművesipari termékek előállítása és az idegenforgalom. A falusi vendéglátás klasszikus értelemben a mezÅ‘gazdaságból származó jövedelmet egészíti ki, azonban magyar viszonyok között a két tevékenység általában alig kapcsolódik egymáshoz. Jelenlegi kutatásunkban arra törekszünk, hogy felmérjük az Észak-alföldi Régióban működÅ‘ mezÅ‘gazdasági vállalkozók, földtulajdonosok hajlandóságát falusi turizmus végzésére, falusi vendéglátók készségét mezÅ‘gazdasági tevékenység folytatására, továbbá a mindkét tevékenységet végzÅ‘ gazdaságok sikeres működésének feltételeit meghatározva, lehatárolni a régió potenciális lehetÅ‘ségeit a mezÅ‘gazdasági tevékenység és a falusi vendéglátó tevékenység összekapcsolására. Vizsgáljuk továbbá azt is, hogy a két tevékenységnek milyen gazdasági eredménye lehet, illetve azok hogyan befolyásolhatják a vizsgált régióban élÅ‘k jövedelemviszonyait. Munkánk során eddig összesen 122 vállalkozás kérdőíves felmérését végeztük el.rural tourism, agriculture, land ownership, land use, expected profit, falusi vendéglátás, mezÅ‘gazdaság, földtulajdonlás, földhasználat, elvárható jövedelem, Agribusiness, Community/Rural/Urban Development,

On the formal statement of the special principle of relativity

The aim of the paper is to develop a proper mathematical formalism which can help to clarify the necessary conceptual plugins to the special principle of relativity and leads to a deeper understanding of the principle in its widest generality.Comment: 15 pages, 3 figure

Operational understanding of the covariance of classical electrodynamics

It is common in the literature on classical electrodynamics and relativity theory that the transformation rules for the basic electrodynamic quantities are derived from the pre-assumption that the equations of electrodynamics are covariant against these---unknown---transformation rules. There are several problems to be raised concerning these derivations. This is, however, not our main concern in this paper. Even if these derivations are regarded as unquestionable, they leave open the following fundamental question: Are the so-obtained transformation rules indeed identical with the true transformation laws of the empirically ascertained electrodynamic quantities? This is of course an empirical question. In this paper, we will answer this question in a purely theoretical framework by applying what J. S. Bell calls “Lorentzian pedagogy”---according to which the laws of physics in any one reference frame account for all physical phenomena, including what a moving observer must see when performs measurement operations with moving measuring devices. We will show that the real transformation laws are indeed identical with the ones obtained by presuming the covariance of the equations of electrodynamics, and that the covariance is indeed satisfied. Beforehand, however, we need to clarify the operational definitions of the fundamental electrodynamic quantities. As we will see, these semantic issues are not as trivial as one might think