When at the end of the 1900s Planck introduced the constant h into the black-body radiation law together with constant k, he provided no explanation of either its meaning or why it had that particular value. He simply introduced it. In reality the history of the constant was far from straightforward. Planck was confident enough to introduce it like this because he had been working on the question for over a year. In this paper we reconstruct the process that began (...) with the first two constants (c' and C. (shrink)

Once one of the main protagonists of history of science, the historiography on quantum theory has recently gone through a process of reconfiguration of methods, research questions and epistemological framework. In this paper, I review the recent developments and propose some reflections on its future evolution.

The foundation of statistical mechanics and the explanation of the success of its methods rest on the fact that the theoretical values of physical quantities (phase averages) may be compared with the results of experimental measurements (infinite time averages). In the 1930s, this problem, called the ergodic problem, was dealt with by ergodic theory that tried to resolve the problem by making reference above all to considerations of a dynamic nature. In the present paper, this solution will be analyzed first, (...) highlighting the fact that its very general nature does not duly consider the specificities of the systems of statistical mechanics. Second, Khinchin’s approach will be presented, that starting with more specific assumptions about the nature of systems, achieves an asymptotic version of the result obtained with ergodic theory. Third, the statistical meaning of Khinchin’s approach will be analyzed and a comparison between this and the point of view of ergodic theory is proposed. It will be demonstrated that the difference consists principally of two different perspectives on the ergodic problem: that of ergodic theory puts the state of equilibrium at the center, while Khinchin’s attempts to generalize the result to non-equilibrium states. (shrink)

J. J. Thomson's discovery of the negatively charged corpuscle in 1897 is customarily regarded as the discovery of the electron. Thomson, however, did not immediately equate the charge of his corpuscle with the unitary charge, that is the ‘electron’, first proposed by Stoney in 1874. The aim of this paper is to clarify the means by which this identification was eventually made. To do this the work carried out by Thomson and his students at the Cavendish Laboratory between 1897 and (...) 1899 has been examined. From this reconstruction it emerges that, following his work on the mass-to-charge ratio of the corpuscle in 1897, Thomson and his school initiated and developed a series of techniques for measuring the charge of the ions. These techniques could not be used directly to measure the charge of the corpuscles because of the conditions required to produce them. Thomson therefore sought some other phenomenon that could be interpreted in terms of corpuscles and which allowed exploitation of the new charge-measuring techniques. He found such a phenomenon in the photoelectric effect, which allowed the measurement of both the charge and the mass-to-charge ratio of the corpuscle to be made. These measurements showed the charge of the corpuscle to be close to that assigned to the ‘electron’, and the two entities gradually became equated with each other. (shrink)

It is often claimed that epistemic bubbles and echo chambers foster post-truth by filtering our access to information and manipulating our epistemic attitude. In this paper, I try to add a further level of analysis by adding the issue of belief formation. Building on cognitive psychology work, I argue for a dual-system theory according to which beliefs derive from a default system and a critical system. One produces beliefs in a quasi-automatic, effortless way, the other in a slow, effortful way. (...) I also argue that digital socio-epistemic environments tend to inculcate disvalues in their agent's epistemic identity, a process that causes the cognitive shortcircuits typical of conspiracy theories. (shrink)

In an article published recently in this journal, one of us reconstructed how in 1899 J. J. Thomson, after having measured the mass-to-charge ratio of the corpuscle , achieved a measurement of its charge and consequently an estimate of its mass, obtaining in this manner ‘direct proof of the existence of particles smaller than the hydrogen atom’. In this paper, starting with an analysis of Zeeman's first measurements on the widening of spectral lines in a magnetic field, we show that (...) the existence of masses smaller than the atom was already a matter of discussion in early 1897, and that a qualitative estimate of the mass of the electron was made even before Thomson's measurements in 1899. In this process an important role was played by a research programme on the structure of matter carried out by Stoney in the latter part of the nineteenth century. This had in many aspects anticipated Zeeman's experimental observations, and its conclusions were in part formalized in the so-called Larmor theorem. (shrink)

There are two basic approaches to the problem of induction:the empirical one, which deems that the possibility of induction depends on how theworld was made (and how it works) and the logical one, which considers the formation(and function) of language. The first is closer to being useful for induction, whilethe second is more rigorous and clearer. The purpose of this paper is to create an empiricalapproach to induction that contains the same formal exactitude as the logical approach.This requires: (a) that (...) the empirical conditions for the induction are enunciatedand (b) that the most important results already obtained from inductive logic are againdemonstrated to be valid. Here we will be dealing only with induction by elimination,namely the analysis of the experimental confutation of a theory. The result will bea rule of refutation that takes into consideration all of the empirical aspect of theexperiment and has each of the asymptotic properties which inductive logic has shown tobe characteristic of induction. (shrink)

Ever since Thomas Kuhn's influential The Structure of Scientific Revolutions (1962), textbooks have suffered a bad reputation. They have been accused of distorting—at times purportedly—history and of feeding students with an unacceptably simplified and optimistic view of science. This attitude started to change only in recent times. With the increase of attention paid not only to how theories are conceived, but also how they are practiced, disseminated, and appropriated, historians have rehabilitated textbooks as a legitimate site of knowledge production. In (...) this paper, I adopt textbooks as an instrument to unfold multiple facets of the culture that allowed quantum physics to flourish between 1900 and the early 1930s. I organize the article around two stories about two major textbooks, i.e., Sommerfeld′s Atombau und Spektrallinien and Dirac′s Principles of Quantum Mechanics. I explore the complex pedagogical cultures underlying these two masterpieces and how they intersect local agendas. (shrink)

An intricate, long, and occasionally heated debate surrounds Boltzmann’s H-theorem (1872) and his combinatorial interpretation of the second law (1877). After almost a century of devoted and knowledgeable scholarship, there is still no agreement as to whether Boltzmann changed his view of the second law after Loschmidt’s 1876 reversibility argument or whether he had already been holding a probabilistic conception for some years at that point. In this paper, I argue that there was no abrupt statistical turn. In the first (...) part, I discuss the development of Boltzmann’s research from 1868 to the formulation of the H-theorem. This reconstruction shows that Boltzmann adopted a pluralistic strategy based on the interplay between a kinetic and a combinatorial approach. Moreover, it shows that the extensive use of asymptotic conditions allowed Boltzmann to bracket the problem of exceptions. In the second part I suggest that both Loschmidt’s challenge and Boltzmann’s response to it did not concern the H-theorem. The close relation between the theorem and the reversibility argument is a consequence of later investigations on the subject. (shrink)

The Kolmogorov-Sinai entropy is a fairly exotic mathematical concept which has recently aroused some interest on the philosophers’ part. The most salient trait of this concept is its working as a junction between such diverse ambits as statistical mechanics, information theory and algorithm theory. In this paper I argue that, in order to understand this very special feature of the Kolmogorov-Sinai entropy, is essential to reconstruct its genealogy. Somewhat surprisingly, this story takes us as far back as the beginning of (...) celestial mechanics and through some of the most exciting developments of mathematical physics of the 19th century. (shrink)

In this paper we analyse the approach to interpreting atomic spectra in the framework of classical physics from the discovery of the electron in 1897 to Bohr's atomic model of 1913. Taken as a whole, efforts in this direction are part of a remarkable intellectual endeavour in which the classical theoretical framework seems to have been exploited to its full potential. By demonstrating the limits and weaknesses of classical physics in solving the problem of spectral emissions, these attempts opened the (...) way to a complete break from traditional thought and the introduction of the new quantum ideas. (shrink)

The recent use of typicality in statistical mechanics for foundational purposes has stirred an important debate involving both philosophers and physicists. While this debate customarily focuses on technical issues, in this paper I try to approach the problem from an epistemological angle. The discussion is driven by two questions: (1) What does typicality add to the concept of measure? (2) What kind of explanation, if any, does typicality yield? By distinguishing the notions of `typicality-as-vast-majority' and `typicality-as-best-exemplar', I argue that the (...) former goes beyond the concept of measure. Furthermore, I also argue that typicality aims at providing us with a form of causal explanation of equilibrium. (shrink)

Most philosophical accounts on scientific theories are affected by three dogmas or ingrained attitudes. These dogmas have led philosophers to choose between analyzing the internal structure of theories or their historical evolution. In this paper, I turn these three dogmas upside down. I argue (i) that mathematical practices are not epistemically neutral, (ii) that the morphology of theories can be very complex, and (iii) that one should view theoretical knowledge as the combination of internal factors and their intrinsic historicity.

The aim of this paper is not only to deal with the concept of infinity, but also to develop some considerations about the epistemological status of cosmology. These problems are connected because from an epistemological point of view, cosmology, meant as the study of the universe as a whole, is not merely a physical (or empirical) science. On the contrary it has an unavoidable metaphysical character which can be found in questions like “why is there this universe (or a universe (...) at all)?”. As a consequence, questions concerning the infinity of the universe in space and time can correctly arise only taking into account this metaphysical character of cosmology. Accordingly, in the following paper it will be shown that two different concepts of physical infinity of the universe (the relativistic one and the inflationary one) rely on two different ways of solution of a metaphysical problem. The difference between these concepts cannot be analysed using the classical distinctions between actual/potential infinity or numerable/continuum infinity, but the introduction of a new “modal” distinction will be necessary. Finally, it will be illustrated the role of a philosophical concept of infinity of the universe. (shrink)

Boltzmann’s equilibrium theory has not received by the scholars the attention it deserves. It was always interpreted as a mere generalization of Maxwell’s work or, in the most favorable case, a sketch of some ideas more consistently developed in the 1872 memoir. In this paper, I try to prove that this view is ungenerous. My claim is that in the theory developed during the period 1866-1871 the generalization of Maxwell’s distribution was mainly a mean to get a more general scope: (...) a theory of the equilibrium of a system of mechanical points from a general point of view. To face this issue Boltzmann analyzed and discussed probabilistic assumptions so that his equilibrium theory cannot be considered a purely mechanical theory. I claim also that the special perspective adopted by Boltzmann and his view about probabilistic requirements played a role in the transition to the non equilibrium theory of 1872. (shrink)

Selective realism is the thesis that some wisely chosen theoretical posits are essential to science and can therefore be considered as true or approximately true. How to choose them wisely, however, is a matter of fierce contention. Generally speaking, we should favor posits that are effectively deployed in successful prediction. In this paper I propose a refinement of the notion of deployment and I argue that selective realism can be extended to include the analysis of how theoretical posits are actually (...) deployed in symbolic practices. (shrink)

This book examines the different areas of knowledge, traditions, and conceptual resources that contributed to the building of Max Planck's theory of radiation. It presents an insightful comparative analysis that not only sheds light upon a fundamental chapter in the history of modern physics, but also enlarges our understanding of how theoreticians work. Coverage offers a deep investigation into the technical aspects behind the theory and extends in time the notion of quantum revolution. It also presents a full-fledged discussion of (...) the combinatorial part of Planck's theory and places emphasis on the epistemological role of mathematical practices. By painstakingly reconstructing both the electromagnetic and the combinatorial part of Planck's black-body theory, the author shows how some apparently merely technical resources, such as the Fourier series, effectively contributed to shape the final form of Planck's theory. For decades, historians have debated the conditions of possibility of Max Planck's discovery as a paradigmatic example of scientific revolution. In particular, the use of combinatorics, which eventually paved the way for the introduction of the quantum hypothesis, has remained a puzzle for experts. This book presents a fresh perspective on this important debate that will appeal to historians and philosophers of science. (shrink)

This paper analyzes the epistemological significance of the problem of induction. In the first section, the foundation of this problem is identified in the thesis of gnoseological dualism: we only know our representations as separate from ‘the world itself’. This thesis will be countered by the thesis of gnoseological monism. In the second section, the implications of Hume’s skeptical thesis will be highlighted and it will be demonstrated how the point of view of gnoseological monism can offer a way out (...) that I call the hermeneutic theory of induction. In the third section, a formal approach is proposed in agreement with this theory. Using tools of the theory of information, this defines the conditions of acceptance or refusal of a hypothesis starting with an experiment. In the fourth section, the epistemological consequences of this approach are analyzed. (shrink)

This book tells the curious story of an unexpected finding that sheds light on a crucial moment in the development of physics: the discovery of artificial radioactivity induced by neutrons. The finding in question is a notebook, clearly written in Fermi's handwriting, which records the frenzied days and nights that Fermi spent experimenting alone, driven by his theoretical ideas on beta decay. The notebook was found by the authors while browsing through documents left by Oscar D'Agostino, the chemist among Fermi's (...) group. From Fermi's notes, they reconstruct with skill and expertise the detailed timeline of the critical days leading up to his vital discovery. While much is already known about the road that led Fermi to his important result, this is the first time that it has been possible to reconstruct precisely when and how the initial evidence of neutron-induced decay was obtained. In relating this fascinating story, the book will be of great interest not only to those with a passion for the history of science but also to a wider audience. (shrink)

Until now studies on the historical development of atomic spectroscopy have focused on three main aspects-its first applications as a method of chemical analysis, the formulation of spectral laws , and the rise of the old quantum theory. These developments of spectroscopy were based on the same assumption: the invariance of the atomic spectrum after fixing the chemical element . This paper shows that running alongside these lines of research there was another, no less important area of study based on (...) the negation of this assumption. The focus of these latter studies was the behaviour of atomic spectra as a function of different working conditions. English astrophysicist Sir Norman Lockyer played a central role in this research. While studying the effect of temperature on spectral lines and comparing stellar spectra with laboratory spectra, he discovered a new class of spectral lines . In an attempt to explain the origin of these lines, Lockyer, at the beginning of 1897 , hypothesized the 'dissociation' of the chemical elements into simplified forms of matter, named proto-elements. Lockyer's studies are mentioned by Thomson in the paper which introduces the corpuscle for the first time. In this paper we have tried to reconstruct the history of Lockyer's proto-elements and highlight the links between them and Thomson's corpuscle. Our analysis has shown that not only the famous studies on discharges in rarefied gases but also Lockyer's stellar spectroscopy played an important role in the work of J. J. Thomson, convincing him that the atom was complex and divisible. (shrink)

This article argues that pseudoscience lacks an adequate philosophical analysis. Using conspiracy theories as a case study, it is claimed that such an analysis needs to go beyond a mere epistemological approach. In the first part, it is shown that the existing philosophical literature shares the assumption that conspiracy theories are primarily deficient scientific hypotheses. This claim is contested, because such an approach can only understand what conspiracy theories fail to be, but not what they are and why people tend (...) to endorse them. To develop an alternative, the second part starts from recent sociology of science, applied to conspiracy theories, that claims that both true and false theories are in need of a symmetrical social explanation. However, this opens the path to relativism because it does not allow for a significant distinction between scientific and conspiracy theories. In the third section an alternative analysis of conspiracy theories is offered, which does not abandon this distinction. Moreover, it is claimed that the most important element of conspiracy theories is not their truth value but rather their symbolic structures of meaning. The aim of conspiracy theories, and perhaps of pseudoscience in general, is then not to know facts about the world, but rather to offer a meaningful framework within which to live. (shrink)

This article takes the scientific study of conspiracy theories itself as an object of inquiry. It looks at the three main frameworks to look at conspiracy theories: a psychological, epistemological and a sociological approach. These different approaches exist somewhat separately and often do not get along. The central claim that follows from a genealogy of these research programs is that the conflicts between these different approaches should be understood not merely as disagreements about how the world works, but as a (...) fundamental disagreement about the underlying diagnosis of what is at stake in conspiracy theories. In other words, the conflicts stem in part from political differences, not merely empirical ones. The purpose of this article is to bring these different diagnoses back into dialogue with each other and to point out that despite their differences, they also have something in common: a concern about the state of contemporary democratic institutions. Depending on which project one subscribes to, conspiracy thinking will appear either as the cause or the solution of these democratic concerns. (shrink)

This article intends to summarise the content of my book Insurgent Universality: An Alternative Legacy of Modernity and expand the meaning of the term ‘universality’. Universality is not defined in abstract legal terms or by juxtaposition vis-à-vis a common enemy. Instead, I clarify the meaning of a more concrete and open practice of universality through historical examples and theories that I excavate from social practices.

The central claim of this article is that post-truth requires a political and socio-economical perspective, rather than a moral or epistemological one. The article consists of two parts. The first part offers a critical examination of the dominant analyses of post-truth in terms of shifting standards of the origin and the evaluation of facts. Moreover, the claim that postmodernism is the cause of post-truth is examined and refuted. In the second part an alternative perspective is developed, centring around the notion (...) of gatekeepers. Rather than linking post-truth to bullshit and postmodernism, it should be understood as a symptom of a contemporary shift in the gatekeepers of truth and knowledge. Knowledge and truth are always mediated in society through the hands of gatekeeping institutions such as journalism or science. Post-truth is a symptom of a broader transformation of the gatekeeping institutions of our current society. It therefore requires a political philosophy of these institutional shifts and the new risks they involve. (shrink)