Acceptance of the quantization of the elementary electrical charge was preceded by a bitter dispute between Robert Millikan and Felix Ehrenhaft, which lasted for many years. Both Millikan and Ehrenhaft obtained very similar experimental results and yet Millikan was led to formulate the elementary electrical charge and Ehrenhaft to fractional charges. There have been four major attempts to reconstruct the historical events that led to the controversy: Holton ; Franklin ; Barnes et al. ; Goodstein. So we have the controversy (...) not only among the original protagonists but also among those who have interpreted the experiment. The objective of this study is a critical appraisal of the four interpretations and an attempt to provide closure to the controversy. It is plausible to suggest that Ehrenhaft's methodology approximated the traditional scientific method, which did not allow him to discard anomalous data. Millikan, on the other hand, in his publications espoused the scientific method but in private was fully aware of the dilemma faced and was forced to select data to uphold his presuppositions. A closure to the controversy is possible if we recognize that Millikan's data selection procedure depended primarily on his commitment to his presuppositions. Franklin's finding that the selection of the drops did not change the value of e but only its statistical error carries little weight as Millikan did not perform Franklin-style analyses that could have justified the exclusion of drops. It is plausible to suggest that had Millikan performed such analyses, he would have included them in his publication in order to provide support for his data selection procedures. In the absence of his presuppositions, Millikan could not tell which was the ‘expected correct’ value of e and the degree of statistical error. Finally, if we try to understand Millikan's handling of data with no reference to his presuppositions, then some degree of ‘misconduct’ can be perceived. Introduction An appraisal of Holton's interpretation An appraisal of Franklin's interpretation An appraisal of Barnes, Bloor and Henry's interpretation An appraisal of Goodstein's interpretation A crucial test: the second drop of 15 March 1912 Conclusion: Is closure possible? (shrink)

This paper is concerned with the problem of experimental error. The prevalent view that experimental errors can be dismissed as a tiresome but trivial blemish on the method of experimentation is criticized. It is stressed that the occurrence of errors in experiments constitutes a permanent feature of the attempt to test theories in the physical world, and this feature deserves proper attention. It is suggested that a classification of types of experimental error may be useful as a heuristic device in (...) studying the nature of these errors. However, the standard classification of systematic and random errors is mathematically based does not focus on the causes of the errors, their origins, or the contexts in which they arise. A new typology of experimental errors is therefore proposed whose criterion is epistemological. This typology reflects the various stages that can be discerned in the execution of an experiment, each stage constituting a category of a certain type of experimental error. The proposed classification consists of four categories which are illustrated by historical cases. (shrink)

The Reality of Knowledge completes a trilogy begun with The Architecture of Knowledge (1980) and Processes of Knowledge (2001). It presents a holistic analysis of knowledge and the reality that is known. The book shows how living things, including humans, construct reality in specific ways that maximize their ability to know it. Different species construct different areas of reality, but they all use the same methods: objectification, categorization, and generalization. Support for this analysis comes from examining certain logical protocols in (...) computer technology, because computer architectures have evolved to emulate human knowledge. (shrink)

Science depends on judgments of the bearing of evidence on theory. Scientists must judge whether an observation or the result of an experiment supports, disconfirms, or is simply irrelevant to a given hypothesis. Similarly, scientists may judge that, given all the available evidence, a hypothesis ought to be accepted as correct or nearly so, rejected as false, or neither. Occasionally, these evidential judgments can be made on deductive grounds. If an experimental result strictly contradicts a hypothesis, then the truth of (...) the data deductively entails the falsity of the hypothesis. In the great majority of cases, however, the connection between evidence and hypothesis is non-demonstrative, or inductive. In particular, this is so whenever a general hypothesis is inferred to be correct on the basis of the available data, since the truth of the data will not deductively entail the truth of the hypothesis. It always remains possible that the hypothesis is false even though the data are correct. (shrink)

This paper aims to defend the use of the notion of experimental individuation, which has recently been developed by Ruey-Lin Chen, as a criterion for the reality of theoretical entities. In short, when scientists experimentally individuate an entity, a realist conclusion about that entity is warranted. We embed this claim regarding experimental individuation within a framework that allows for other criteria of reality. And we understand so-called retail arguments regarding the reality of a particular theoretical entity as arguments that concern (...) choosing an appropriate criterion of reality for that entity and determining whether the relevant first-order scientific evidence satisfies that criterion. We argue that such retail arguments are philosophical because defending criteria of reality, and showing that they are or are not satisfied in particular cases, involves work that is distinctively philosophical. And we illustrate this philosophical work by applying our criterion of experimental individuation to three historical cases: Davy’s potassium, Lavoisier’s muriatic radical, and Thomson’s electrified particles. (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 paper examines the debate in the late 19th and early 20th centuries over the acceptability of atomic and molecular physics. It focuses on three prominent figures: Maxwell, who defended atomic physics, Ostwald, who initially rejected it but changed his mind as a result of experiments by Thomson and Perrin, and Duhem, who never accepted it. Each scientist defended the position he did in the light of strongly held methodological views concerning empirical evidence. The paper critically evaluates each of (...) these methodological positions. (shrink)

This paper attends to two main tasks. First, I introduce the notion of perspectival disagreement in science. Second, I relate perspectival disagreement in science to the broader issue of realism about science: how to maintain realist ontological commitments in the face of perspectival disagreement among scientists? I argue that often enough perspectival disagreement is not at the level of the scientific knowledge claims but rather of the methodological and justificatory principles. I introduce and clarify the notion of ‘agreeing-whilst-perspectivally-disagreeing’ with an (...) episode from the history of modern physics: namely, how we came to agree about the electric charge as a minimal natural unit despite different scientific perspectives and associated data-to-phenomena inferences available for it in the period 1897–1906. (shrink)

Magnus and Callender argue that we ought to focus on retail arguments, which are arguments regarding the existence of particular kinds of theoretical entities, as opposed to theoretical entities in general. However, scientists are the ones who put forward retail arguments, and it’s unclear how philosophers can engage with such arguments. We argue that philosophers can engage with retail arguments by providing criteria that they must satisfy in order to demonstrate the existence of theoretical entities. We put forward experimental individuation (...) as such a criterion---when scientists experimentally individuate an entity, a realist conclusion about that entity is warranted. (shrink)

The historical variation of scientific knowledge has lent itself to the development of historical epistemology, which attempts to historicize the origin and establishment of knowledge claims. The questions I address in this paper revolve around the historicity of the objects of those claims: How and why do new scientific objects appear? What exactly comes into being in such cases? Do scientific objects evolve over time and in what ways? I put forward and defend two theses: First, the ontology of science (...) is so rich and variegated that there are no universally valid answers to these questions. Second, we need a pluralist account of scientific objects, a pluralist metaphysics that can do justice to their rich diversity and their various modes of being and becoming. I then focus on hidden objects, which are supposed to be part of the permanent furniture of the universe, and I discuss their birth and historicity: They emerge when various phenomena coalesce as manifestations of a single hidden cause and their representations change over time. Finally, I examine the conditions under which an evolving representation may still refer to the same object and I illustrate my argument drawing upon the early history of electrons. (shrink)

La tesis de la subdeterminación empírica representa uno de los mayores desafíos contemporáneos en contra del realismo científico, sin embargo, frecuentemente se le ha considerado como un reto coherente y se ha buscado una forma de atenuar su impacto ya sea mitigando alguna posición realista, o bien, atacando alguno de sus presupuestos más problemáticos. En este ensayo defiendo un argumento en su contra, a saber, que es una tesis que nos conduce a una reductio y que semejante resultado echa por (...) tierra su supuesta plausibilidad como una tesis antirrealista. (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)

This paper offers a novel way of reconstructing conceptual change in empirical theories. Changes occur in terms of the structure of the dimensions—that is to say, the conceptual spaces—underlying the conceptual framework within which a given theory is formulated. Five types of changes are identified: (1) addition or deletion of special laws, (2) change in scale or metric, (3) change in the importance of dimensions, (4) change in the separability of dimensions, and (5) addition or deletion of dimensions. Given this (...) classification, the conceptual development of empirical theories becomes more gradual and rationalizable. Only the most extreme type—replacement of dimensions—comes close to a revolution. The five types are exemplified and applied in a case study on the development within physics from the original Newtonian mechanics to special relativity theory. (shrink)

This paper attends to two main tasks. First, I introduce the notion of perspectival disagreement in science. Second, I relate perspectival disagreement in science to the broader issue of realism about science: how to maintain realist ontological commitments in the face of perspectival disagreement among scientists? I argue that often enough perspectival disagreement is not at the level of the scientific knowledge claims but rather of the methodological and justificatory principles. I introduce and clarify the notion of ‘agreeing-whilst-perspectivally-disagreeing’ with an (...) episode from the history of modern physics: namely, how we came to agree about the electric charge as a minimal natural unit despite different scientific perspectives and associated data-to-phenomena inferences available for it in the period 1897–1906. (shrink)

The history of the luminiferous ether is sketched with a view to ascertaining what factors may have kept this idea alive until 1905, when Einstein declared it superfluous.

Prompted by Hasok Chang’s conception of the history and philosophy of science (HPS) as the continuation of science by other means, I examine the possibility of obtaining scientific knowledge through philosophical criticism and reflection, in the light of four historical cases, concerning (i) the role of absolute space in Newtonian dynamics, (ii) the purported contraction of rods and retardation of clocks in Special Relativity, (iii) the reality of the electromagnetic ether, and (iv) the so-called problem of time’s arrow. In all (...) four cases it is clear that a better understanding of such matters can be achieved —and has been achieved— through conceptual analysis. On the other hand, however, it would seem that this kind of advance has more to do with philosophical questions in science than with narrowly scientific questions. Hence, if HPS in effect continues the work of science by other means, it could well be doing it for other ends than those that working scientists ordinarily have in mind. (shrink)

I reappraise in detail Hertz's cathode ray experiments. I show that, contrary to Buchwald 's evaluation, the core experiment establishing the electrostatic properties of the rays was successfully replicated by Perrin and Thomson. Buchwald 's discussion of 'current purification' is shown to be a red herring. My investigation of the origin of Buchwald 's misinterpretation of this episode reveals that he was led astray by a focus on what Hertz 'could do'-his experimental resources. I argue that one should focus instead (...) on what Hertz wanted to achieve-his experimental goals. Focusing on these goals, I find that his explicit and implicit requirements for a successful investigation of the rays' properties are met by Perrin and Thomson. Thus, even by Hertz's standards, they did indeed replicate his experiment. (shrink)

In 1897 physicists took the first e/m measurements at electrons, the consequence was a revival of the atomistic ideas in physics. The researches in geophysics also contributed to the construction of the modern physics. Four examples are dealt with this essay. 1) In 1899 J. J. Thomson was able to carry out the first direct determination of elementary electric charge with the help of the conformity with the natural laws at the formation of fog, found by C. T. R. Wilson. (...) 2) The cloud-chamber, called after C. T. R. Wilson, was the result of various constructions of for- or cloud-chambers, in it there were shown for the first time the tracks of α- and β-particles. 3) At the exploration of the photoelectric effect of the sunlight (especially of the ultraviolet share) Elster and Geitel made essential preliminary studies for the lightquanta-hypothesis of Einstein. 4) Elster and Geitel detected radioactive substances in the atmosphere and in the soil to be the main source of the atmospheric electricity. (shrink)

By understanding laws of nature as geometrical rather than linguistic entities, this paper addresses how to describe theory structures and how to evaluate their continuity. Relying on conceptual spaces as a modelling tool, we focus on the conceptual framework an empirical theory presupposes, thus obtain a geometrical representation of a theory’s structure. We stress the relevance of measurement procedures in separating conceptual from empirical structures. This lets our understanding of scientific laws come closer to scientific practice, and avoids a widely (...) recognised deficit in current philosophy of science accounts, namely to risk a collapse of the physical into the mathematical. (shrink)