We give a overview of the main areas in theoretical physics, with emphasis on their relation to Lagrangian formalism in classical mechanics. This review covers classical mechanics; the road from classical mechanics to Schrödinger’s quantum mechanics; electromagnetism, special and general relativity, and gauge field theory and the Higgs mechanism. We shun mathematical rigor in favor of a straightforward presentation.

If you wish to learn from the theoretical physicist anything about the methods which he uses, I would give you the following piece of advice: Don't listen to his words, examine his achievements. For to the discoverer in that field, the constructions of his imagination appear so necessary and so natural that he is apt to treat them not as the creations of his thoughts but as given realities.

The paper aims to show how Japanese theoretical physics groups emerged between the First and Second World Wars. First, it will be argued that by the early 1930s the Japanese physics community had been predominantly inclined towards experimental physics and that several academic, cultural, and social factors had worked for the maintenance of this status quo. Next, how the situation slowly changed during the early 1930s, and how the young theoretical physicists successfully established a bridgehead (...) during the mid-1930s will be analysed. Four different elements are suggested: the dazzling success of quantum mechanics and its spread in the West; the dominance of experimental physics and its effect on the university system; cultural/social influence; and the emergence of the research network. (shrink)

I characterize Bishop's constructive mathematics as an alternative to classical mathematics, which makes use of the actual infinity. From the history an accurate investigation of past physical theories I obtianed some ones - mainly Lazare Carnot's mechanics and Sadi Carnot's thermodynamics - which are alternative to the dominant theories - e.g. Newtopn's mechanics. The way to link together mathematics to theoretical physics is generalized and some general considerations, in particualr on the geoemtry in theoretical physics, are (...) obtained.that. (shrink)

The paper explicates the stages of the author’s philosophical evolution in the light of Kopnin’s ideas and heritage. Starting from Kopnin’s understanding of dialectical materialism, the author has stated that category transformations of physics has opened from conceptualization of immutability to mutability and then to interaction, evolvement and emergence. He has connected the problem of physical cognition universals with an elaboration of the specific system of tools and methods of identifying, individuating and distinguishing objects from a scientific theory domain. (...) The role of vacuum conception and the idea of existence (actual and potential, observable and nonobservable, virtual and hidden) types were analyzed. In collaboration with S.Crymski heuristic and regulative functions of categories of substance, world as a whole as well as postulates of relativity and absoluteness, and anthropic and self-development principles were singled out. Elaborating Kopnin’s view of scientific theories as a practically effective and relatively true mapping of their domains, the author in collaboration with M. Burgin have originated the unified structure-nominative reconstruction (model) of scientific theory as a knowledge system. According to it, every scientific knowledge system includes hierarchically organized and complex subsystems that partially and separately have been studied by standard, structuralist, operationalist, problem-solving, axiological and other directions of the current philosophy of science. 1) The logico-linguistic subsystem represents and normalizes by means of different, including mathematical, languages and normalizes and logical calculi the knowledge available on objects under study. 2) The model-representing subsystem comprises peculiar to the knowledge system ways of their modeling and understanding. 3) The pragmatic-procedural subsystem contains general and unique to the knowledge system operations, methods, procedures, algorithms and programs. 4) From the viewpoint of the problem-heuristic subsystem, the knowledge system is a unique way of setting and resolving questions, problems, puzzles and tasks of cognition of objects into question. It also includes various heuristics and estimations (truth, consistency, beauty, efficacy, adequacy, heuristicity etc) of components and structures of the knowledge system. 5) The subsystem of links fixes interrelations between above-mentioned components, structures and subsystems of the knowledge system. The structure-nominative reconstruction has been used in the philosophical and comparative case-studies of mathematical, physical, economic, legal, political, pedagogical, social, and sociological theories. It has enlarged the collection of knowledge structures, connected, for instance, with a multitude of theoreticity levels and with an application of numerous mathematical languages. It has deepened the comprehension of relations between the main directions of current philosophy of science. They are interpreted as dealing mainly with isolated subsystems of scientific theory. This reconstruction has disclosed a variety of undetected knowledge structures, associated also, for instance, with principles of symmetry and supersymmetry and with laws of various levels and degrees. In cooperation with the physicist Olexander Gabovich the modified structure-nominative reconstruction is in the processes of development and justification. Ideas and concepts were also in the center of Kopnin’s cognitive activity. The author has suggested and elaborated the triplet model of concepts. According to it, any scientific concept is a dependent on cognitive situation, dynamical, multifunctional state of scientist’s thinking, and available knowledge system. A concept is modeled as being consisted from three interrelated structures. 1) The concept base characterizes objects falling under a concept as well as their properties and relations. In terms of volume and content the logical modeling reveals partially only the concept base. 2) The concept representing part includes structures and means (names, statements, abstract properties, quantitative values of object properties and relations, mathematical equations and their systems, theoretical models etc.) of object representation in the appropriate knowledge system. 3) The linkage unites a structures and procedures that connect components from the abovementioned structures. The partial cases of the triplet model are logical, information, two-tired, standard, exemplar, prototype, knowledge-dependent and other concept models. It has introduced the triplet classification that comprises several hundreds of concept types. Different kinds of fuzziness are distinguished. Even the most precise and exact concepts are fuzzy in some triplet aspect. The notions of relations between real scientific concepts are essentially extended. For example, the definition and strict analysis of such relations between concepts as formalization, quantification, mathematization, generalization, fuzzification, and various kinds of identity are proposed. The concepts «PLANET» and «ELEMENTARY PARTICLE» and some of their metamorphoses were analyzed in triplet terms. The Kopnin’s methodology and epistemology of cognition was being used for creating conception of the philosophy of law as elaborating of understanding, justification, estimating and criticizing legal system. The basic information on the major directions in current Western philosophy of law (legal realism, feminism, criticism, postmodernism, economical analysis of law etc.) is firstly introduced to the Ukrainian audience. The classification of more than fifty directions in modern legal philosophy is suggested. Some results of historical, linguistic, scientometric and philosophic-legal studies of the present state of Ukrainian academic science are given. (shrink)

In France, as in other European countries, especially Britain and Germany, the nineteenth century was a period of great progress and achievement in science. This would still have been true if Claude Bernard and Louis Pasteur had been the only outstanding French scientists of the nineteenth century, whereas there were, of course, many others apart from an impressive number of brilliant French mathematicians. Nevertheless, although it was a great century for French science there was perhaps something rather disappointing about it, (...) and something rather ingrowing about the attitude of French scientists towards scientific developments in other countries. For example, the French took it hard that the creator of the theory of evolution should have been an Englishman, remembering too late Darwin's predecessor Lamarck, and they certainly were very slow in accepting Darwin's theory of evolution.1 Again, the French may have felt that after the important contributions of French scientists such as Coulomb, Poisson, Biot and, above all, Ampère, the theory of electricity and magnetism which is today principally associated with the names of Faraday and Maxwell should have been created by a Frenchman. Once again this new theory was only accepted very slowly and hesitantly, and even unwillingly, in France—one thinks, for example, of the criticisms levelled at the theory by Pierre Duhem in his “The Aim and Structure of Physical Theory”.2 Of course it might be that if one knew how to weigh properly the various achievements of French scientists in different branches of science one would find that, allowing for her rather static population during the nineteenth century, thetotalcontribution of France compared well with those of Britain and Germany. Nevertheless, in one case at least, that of theoretical physics, there seems to have been an unmistakable failure to live up to the promise of the beginning of the century. The purpose of this paper is to advance possible reasons to explain this failure. (shrink)

The present article considers Giulio Racah’s contributions to general physical theory and his establishment of theoretical physics as a discipline in Israel. Racah developed mathematical methods that are based on tensor operators and continuous groups. These methods revolutionized spectroscopy. Currently, these are essential research tools in atomic, nuclear and elementary particle physics. He himself applied them to modernizing theoretical atomic spectroscopy. Racah laid the foundations of theoretical physics in Israel. He educated several generations of (...) Israeli physicists, and put Israel on the world map of physics. (shrink)

This chapter explores some fundamental consequences of the correspondence between physical process and computations. Most physical questions may be answerable only through irreducible amounts of computation. Those that concern idealized limits of infinite time, volume, or numerical precision can require arbitrarily long computations, and so be considered formally undecidable. The behavior of a physical system may always be calculated by simulating explicitly each step in its evolution. Much of theoretical physics has, however, been concerned with devising shorter methods (...) of calculation that reproduce the outcome without tracing each step. Computational irreducibility is common among the systems investigated in mathematics and computation theory, but it may well be the exception rather than the rule, since most physical questions may be answerable only through irreducible amounts of computation. (shrink)

It is easy to show that in many natural axiomatic formulations of physical and even mathematical theories, there are many superfluous concepts usually assumed as primitive. This happens mainly when these theories are formulated in the language of standard set theories, such as Zermelo–Fraenkel’s. In 1925, John von Neumann created a set theory where sets are definable by means of functions. We provide a reformulation of von Neumann’s set theory and show that it can be used to formulate physical and (...) mathematical theories with a lower number of primitive concepts very naturally. Our basic proposal is to offer a new kind of set-theoretic language that offers advantages with respect to the standard approaches, since it doesn’t introduce dispensable primitive concepts. We show how the proposal works by considering significant physical theories, such as non-relativistic classical particle mechanics and classical field theories, as well as a well-known mathematical theory, namely, group theory. This is a first step of a research program we intend to pursue. (shrink)

The modern theoretical physicist is a strange creature. Perhaps in every age the theoretical physicist has seemed so to his contemporaries who took the trouble to observe and think about him. There seems, for example, something almost too magical in the uncanny way in which he pulls a brand new atomic particle out of a theory, a way that reminds us of a rabbit being produced out of a hat. This is usually done in an off-hand manner with (...) a considerable amount of patter of a highly abstract symbolic character but with a few words inserted in the right places for the benefit of the experimental physicist and a final prediction that if the experimenter does thus and so in the laboratory he will find a certain result. No wonder the observer marvels when the answer comes out right. But as he thinks further he is inclined to wonder whether it is necessary or desirable for the details of the process which led to the result to be so unintelligible. For unintelligible they seem to be to a great many people who are directly concerned with their understanding, to the people who for years have been laboring under the belief that they are engaged in the task of finding out how Nature works. What is this curious process whose whole task, according to one distinguished exponent of it, is merely to predict experimental results, and what is its future likely to be? These are the questions we are setting for ourselves in the present discussion. It is unlikely that the answers given here will satisfy everybody, but it is reasonably certain that nobody who aspires to an interest in science can fail to attach some meaning to them whether or not he agrees. (shrink)

Examples of theory development in quantum field theory and in S-matrix theory are related to three questions of interest to the philosophy of science. The first is the central role of highly abstract, mathematical models in the creation of theories. Second, the process of creation and justification actually used make it plausible that a successful theory is equally well characterized as being stable against attack rather than as being objectively correct. Lastly, the issue of the reality of theoretical entities (...) is discussed in light of this representation of theory generation and selection. (shrink)

The history and philosophy of science are destined to play a fundamental role in an epoch marked by a major scientific revolution. This ongoing revolution, principally affecting mathematics and physics, entails a profound upheaval of our conception of space, space–time, and, consequently, of natural laws themselves. Briefly, this revolution can be summarized by the following two trends: by the search for a unified theory of the four fundamental forces of nature, which are known, as of now, as gravity, electromagnetism, (...) and strong and weak nuclear forces; by the search for new mathematical concepts capable of elucidating and therefore explaining such a relationship. In fact, the first search is essentially dependent on the second; that is to say, that in order for a new theory of physics to come to light, the development of a deeper geometric theory capable of explaining the structure of space–time on a quantum scale appears to be necessary. On careful consideration, we notice that both of these developments converge in the direction of a unitary and fundamental tendency of modern science—which is the geometrization of theoretical physics and of natural sciences. This new emergent situation carries within it a profound conceptual change, affecting the way in which relations are conceived of, first and foremost, between mathematics and physics. This new paradigm can be summed up by the intimately interdependent points: the immense variety of physical phenomena and of natural forms follows from the equally infinite variety of geometric and topological objects that can be made out in space and from which space is made up; the second point, which ensues from the former one and which is of great historical and epistemological significance, is that mathematics is involved in rather than applied to phenomena. In other words, phenomena are effects that emerge from the geometrical structure of space–time. There is no doubt that this new conception of the relationship between the universe of mathematical ideas and objects and the world of natural phenomena is the true scientific revolution of our century, of great conceptual importance, and consequently, capable of changing our view of science and of nature at one and the same time. It is all at once of a scientific, philosophical and aesthetic order. (shrink)

In this paper I argue in favour of a moderate and selective version of scientific realism with respect to the existence of some physical theoretical objects and the truth of some statements about them. The analysis of common sense or ordinary experience reveals that existence and truth assertions concerning familiar objects are warranted if they satisfy what we call the criteria of presence and invariance. Ordinary objects exemplify a form or a structure determined by constant and changing features with (...) respect to the variation of the conditions of observation and a content given in sensory presence. It is claimed that some theoretical physical objects that possess a structure or a form determined by invariant and variable characteristics relatively to a specified group of transformations and a content provided by observations on which the measurement of those characteristics is grounded can also be justifiably asserted to exist. We further show that this defence of scientific realism in physics doesn't fall prey to the objections that have been raised against the usual vindication of scientific realism based on the no-miracle argument. Some standard objections to scientific realism, such as the underdetermination of theories by observations and the pessimistic meta-induction, are examined and shown to be unconvincing. (shrink)

This book explores the rise of theoretical physics in 19th century Germany. The authors show how the junior second physicist in German universities over time became the theoretical physicist, of equal standing to the experimental physicist. Gustav Kirchhoff, Hermann von Helmholtz, and Max Planck are among the great German theoretical physicists whose work and career are examined in this book. Physics was then the only natural science in which theoretical work developed into a major (...) teaching and research specialty in its own right. Readers will discover how German physicists arrived at a well-defined field of theoretical physics with well understood and generally accepted goals and needs. The authors explain the nature of the work of theoretical physics with many examples, taking care always to locate the research within the workplace. The book is a revised and shortened version of Intellectual Mastery of Nature: Theoretical Physics from Ohm to Einstein, a two-volume work by the same authors. This new edition represents a reformulation of the larger work. It retains what is most important in the original work, while including new material, sharpening discussions, and making the research more accessible to readers. It presents a thorough examination of a seminal era in physics. (shrink)

Challenging the image of physics as dry and dusty, The Beautiful Invisible shows that this highly abstract science is in fact teeming with beautiful concepts, ...

The art of memory started with Aristotle’s questions on memory. During its long evolution, it had important contributions from alchemists, was transformed by Ramon Llull and apparently ended with Giordano Bruno, who was considered the best known representative of this art. This tradition did not disappear, but lives in the formulations of our modern scientific theories. From its initial form as a method of keeping information via associations, it became a principle of classification and structuring of knowledge. This principle, which (...) we here name differentiation with stratification, is a structural design behind classical mechanics. Integrating two different traditions of science in one structure, this physical theory became the modern paradigm of science. In this paper, we show that this principle can also be formulated as a set of questions. This is done via an analysis of theories, based on the epistemology of observational realism. A combination of Rudolph Carnap’s concept of theory as a system of observational and theoretical languages, with a criterion for separating observational languages, based on analytical psychology, shapes this epistemology. The ‘nuclear’ role of the observational laws and the differentiations from these nucleus, reproducing the general cases of phenomena, reveals the memory art’s heritage in the theories. Here in this paper we argue that this design is also present in special relativity and in quantum mechanics. (shrink)

‘‘The strange Story of the Concept which inaugurated Modern Theoretical Physics’’ is the title of a lecture which I delivered on the invitation of Professor Franco Selleri at the University of Bari about 20 years ago. Since Professor Selleri himself has written several interesting papers on this concept and since the centennial of the birth of modern theoretical physics will be celebrated soon, I found it appropriate to dedicate this essay, containing so far unpublished critical and (...) historical comments on this concept, to Professor Selleri on the occasion of his 70th birthday. It should be emphasized that the critical comments in this essay are not intended to question the validity of the theory initiated by this concept, a theory which in the realm of its applicability is daily corroborated by numerous experiments in high-energy laboratories all over the world. Although these critical remarks refer almost exclusively to the first publication of this theory, a publication which has been hailed as ‘‘the most important paper written in the 20th century,’’ they discuss profound problems of general importance for the study of the foundations of physics. (shrink)

Steen Brock paints a cross-disciplinary picture of the philosophical and scientific background for the rise of the quantum theory. He accounts for the unity of Kantian metaphysics of Nature, the Helmholtzian principles, and the Hamiltonian methods of modern pre-quantum physics. Brock shows how Planck's vision of a generalization of classical physics implies that the original quantum mechanics of Heisenberg can be regarded as a successful attempt to maintain this modern unity of physics.However, for Niels Bohr, the unity (...) of science and metaphysics did not end in the world of physics. The development of quantum physics had general implications both for other sciences and for various philosophical issues. Brock discusses these matters with respect to recent topics within the philosophy of science and major interpretations of Bohr's ideas. The author invites the reader to follow a long andwinding route of thought which, in the end, culminates in Bohr's ideas of complementarity, culture and Spirit. (shrink)

The call to re-envision theoretical psychology comes after more than a half century of theorists’ efforts to re-envision psychological science. Especially prominent is persistent critique of mainstream psychology’s deployment of the ontological and epistemic templates of the natural sciences, in theorists’ multifaceted mission to replace that metatheoretical grounding with one deemed properly suited to a thoroughgoing psychological science of lived experience. Despite anticipated objection, I call for consideration of boundary-pushing trends and challenges in the natural sciences, especially in theory (...) and philosophy of physics, with an eye toward inspiring theoretical psychologists and mainstream psychologists anew. I also draw attention to the use of relevant findings of mainstream psychological scientists by philosophers of psychology who ask traditional philosophical questions nonetheless. This use mirrors the use of relevant findings of biological scientists by philosophers of biology within the burgeoning field of biophilosophy, in which I find an apt analogue to what I herein call “psycphilosophy.” By adopting a more mutual, relational attitude toward disciplines that have heretofore been dismissed, theoretical psychologists may attain a better position from which to make more constructive and productive contact with mainstream psychological scientists—contact that may facilitate the impact on the mainstream that has to date eluded theorists. (shrink)

It is shown by means of general principles and specific examples that, contrary to a long-standing misconception, the modern mathematical physics of compressible fluid dynamics provides a generally consistent and efficient language for describing many seemingly fundamental physical phenomena. It is shown to be appropriate for describing electric and gravitational force fields, the quantized structure of charged elementary particles, the speed of light propagation, relativistic phenomena, the inertia of matter, the expansion of the universe, and the physical nature of (...) time. New avenues and opportunities for fundamental theoretical research are thereby illuminated. (shrink)

The aftermath of the Second World War represented a major turning point in the history of French and European physical sciences. The physicist's profession was profoundly restructured, and in this transition the role of internationalism changed tremendously. Transnational circulation became a major part of research training. This article examines the conditions of possibility for this transformation, by focusing on the case of the summer school for theoretical physics created in 1951 by the young Cécile Morette (1922–2017), just in (...) front of Mont Blanc, at Les Houches. First I show that ultimately it was only thanks to extremely specific and intertwined social positions and dispositions, in terms of class and gender (derived from her socialization as an expecteddame de la bourgeoisie), and through the interactions between such social attributes and a dramatic life event, that Morette managed to gather a network diverse, powerful and transnational enough to create this institution. Then, following the first years of this school, I show how it became an international model, paving the way to new articulations between the local, the national and the global scales, even beyond the Cold War oppositions. (shrink)

Nishida Kitarō1, the founder of the Kyoto school of philosophy, often stated that his philosophy of Absolute Nothingness, which had in part been inspired by Zen Buddhism, was not a kind of mysticism. In his last unfinished essay, Watakushi no ronri ni tsuite he complained that his logic of absolutely contradictory self-identity had not been understood by the academic world, and its meaning had been distorted. Nishida decided that the only way of clarifying his philosophical standpoint was to redefine the (...) concepts of 'mind' and 'logic' by showing the relation of the philosophy of Absolute Nothingness to the... (shrink)

In response to Cushing it is urged that the vicissitudes of quantum field theory do not press towards a nonrealist attitude towards the theory as strongly as he suggests. A variety of issues which Redhead raises are taken up, including photon localizability, the wave-particle distinction in the classical limit, and the interpretation of quantum statistics, vacuum fluctuations, virtual particles, and creation and annihilation operators. It is urged that quantum field theory harbors an unacknowledged inconsistency connected with the fact that the (...) zero point energy has observable consequences, while to avoid infinities it must be "thrown away". Finally, Redhead's conception of ephemerals is pressed and the paper concludes with the suggestion that the particle concept largely drops out of quantum field theory. (shrink)

R.I.G. Hughes presents a series of eight philosophical essays on the theoretical practices of physics. The first two essays examine these practices as they appear in physicists' treatises (e.g. Newton's Principia and Opticks ) and journal articles (by Einstein, Bohm and Pines, Aharonov and Bohm). By treating these publications as texts, Hughes casts the philosopher of science in the role of critic. This premise guides the following 6 essays which deal with various concerns of philosophy of physics (...) such as laws, disunities, models and representation, computer simulation, explanation, and the discourse of physics. (shrink)

A review of *Niels Bohr’s Philosophy of Quantum Physics in the Light of the Helmholtzian Tradition of Theoretical Physics *.