Une analyse des concepts d'heuristique et de tolérance méthodologique développée par Lakatos, basée sur l'article "Falsification et méthodologie des programmes de recherche scientifique", publié pour la première fois en 1970, puis dans l'ouvrage La méthodologie des programmes de recherche scientifique, volume I. J'ai analysé dans ce texte l'exemplifiant de l'auteur pour le programme de recherche de l'émission de lumière (en physique quantique au début). Un exemple détaillé des concepts est présenté par Lakatos dans la section "Effet de Newton sur les (...) normes scientifiques" du même livre. J'ai également fait souvent référence au livre Preuves et Réfutations, publié par Lakatos en 1976, dans lequel il expose sa vision heuristique par une application directe à l'évolution des mathématiques. J'ai également fait référence à des articles d'autres auteurs pour l'analyse des deux concepts dans la vision de Lakatos. SOMMAIRE: Abstract 1 Vue d'ensemble 1.1 Le falsificationnisme dogmatique (ou naturaliste) 1.2 La falsification méthodologique 1.3 La falsification méthodologique sophistiquée 2. La tolérance méthodologique 3 L'heuristique 3.1 Heuristique négative : le « noyau dur » du programme 3.2 L'heuristique positive : la « ceinture de protection » du programme 3.3 Bohr : un exemple de programme de recherche 3.4 Preuves et Réfutations 4 Conclusions Bibliographie DOI: 10.13140/RG.2.2.30348.46729 . (shrink)

This Target paper is about the hard problem of phenomenal consciousness (i.e., how is subjective experience possible given the scientific presumption that everything from molecules to minerals to minds is wholly physical?). I first argue that one of the most valuable tools in the scientific arsenal (metaphor) cannot be recruited to address the hard problem due to the inability to forge connections between the stubborn fact of subjective experience and physically grounded models of scientific explanation. I then argue that adherence (...) to the physicalist tenets of contemporary science has a limiting effect on a full appreciation of the phenomenon under discussion. (shrink)

Pentru a analiza conceptele de euristica și toleranță metodologică dezvoltate de Lakatos, m-am concentrat pe secțiunea ”Falsification and the methodology of scientific research programmes”, publicată pentru prima dată ca articol în 1970 și apoi în cartea The methodology of scientific research programmes, Volume I (Lakatos 1978). Am analizat, în acest text, exemplificarea autorului pentru programul de cercetare al emisiei de lumină (în fizica cuantică timpurie) al lui Bohr. O exemplificare detaliată a conceptelor este prezentată de Lakatos în secțiunea ”Newton's effect (...) on scientific standards” din aceeași carte. De asemenea, am făcut dese referiri la cartea Proofs and Refutations (Lakatos 1976) publicată de Lakatos în 1976, în care expune viziunea sa euristică printr-o aplicare directă la evoluția matematicii, și am apelat și la articole ale altor autori pentru analiza celor două concepte în viziunea lui Lakatos. -/- Cuvinte cheie: Imre Lakatos, euristica, toleranța metodologică -/- CUPRINS -/- Abstract 1 Prezentarea generală 1.1 Falsificaţionismul dogmatic (sau naturalist) 1.2 Falsificarea metodologică 1.3 Falsificaţionismul metodologic sofisticat 2 Toleranţa metodologică 3 Euristica 3.1 Euristica negativă: "nucleul dur” al programului 3.2 Euristica pozitivă: "centura de protecţie" a programului 3.3 Bohr: un exemplu de program de cercetare 3.4 Proofs and Refutations 4 Concluzii Bibliografie -/- DOI: 10.13140/RG.2.2.35405.28649. (shrink)

Hydrogen, an atom composed of a single proton and electron, is the fundamental and most abundant element in the universe. Hydrogen composes approximately 90% of the visible universe. As we all know there are different types of energies linked with proton –electron system due to the fundamental forces in any atom such as Kinetic energy, Electrostatic energy,Gravitational energy etc. In quantum framework, Gravity is a very weak force and it’s equivalence with other forces were once thought impossible. I strongly believe (...) that all energies are one or the other forms of a single energy and to prove that all energies are a fraction or part of rest mass energy mec^2. In this paper, I’ve tried to define a new equation unifying all the energies of a hydrogen atom. (shrink)

There is confusion among scholars of Bohr as to whether he should be categorized as an instrumentalist (see Faye 1991) or a realist (see Folse 1985). I argue that Bohr is a realist, and that the confusion is due to the fact that he holds a very special view of realism, which did not coincide with the philosophers’ views. His approach was sometimes labelled instrumentalist and other times realist, because he was an instrumentalist on the theoretical level, but a realist (...) on the level of models. Such a realist position is what I call phenomenological realism. In this paper, and by taking Bohr’s debate with Einstein as a paradigm, I try to prove that Bohr was such a realist. (shrink)

The late 19th-century Ignorabimus controversy over the limits of scientific knowledge has often been characterized as proclaiming the end of intellectual progress, and by implication, as plunging Germany into a crisis of pessimism from which Liberalism never recovered. My research supports the opposite interpretation. The initiator of the Ignorabimus controversy, Emil du Bois-Reymond, was a physiologist who worked his whole life against the forces of obscurantism, whether they came from the Catholic and Conservative Right or the scientistic and millenarian Left. (...) Du Bois-Reymond’s doubt that scientists would ever elucidate consciousness must therefore be seen as an endorsement, and not a rejection, of his faith in reason. (shrink)

Entropy is ubiquitous in physics, and it plays important roles in numerous other disciplines ranging from logic and statistics to biology and economics. However, a closer look reveals a complicated picture: entropy is defined differently in different contexts, and even within the same domain different notions of entropy are at work. Some of these are defined in terms of probabilities, others are not. The aim of this chapter is to arrive at an understanding of some of the most important notions (...) of entropy and to clarify the relations between them, After setting the stage by introducing the thermodynamic entropy, we discuss notions of entropy in information theory, statistical mechanics, dynamical systems theory and fractal geometry. (shrink)

Counterfactual reasoning has been used to account for many aspects of scientific reasoning. More recently, it has also been used to account for the scientific practice of modeling. Truth in a model is truth in a situation considered as counterfactual. When we reason with models, we reason with counterfactuals. Focusing on selected models like Bohr’s atom model or models of population dynamics, I present an account of how the imaginative development of a counterfactual supposition leads us from reality to interesting (...) model assumptions; how it guides our reasoning from these assumptions to interesting consequences for the model scenario via counterfactual entailment; and how it leads us back to conclusions on real target phenomena. (shrink)

The central motivation behind the scientific realism debate is explaining the impressive success of scientific theories. The debate has been dominated by two rival types of explanations: the first relies on some sort of static, referentially transparent relationship between the theory and the unobservable world, such as truthlikeness, representation, or structural similarity; the second relies on no robust relationship between the theory and unobservable reality at all, and instead draws on predictive similarity and the stringent methodology of science to explain (...) success. I argue that this is a false dichotomy, at least insofar as dynamical theories are concerned. The best explanation of the success of dynamical theories, I argue, must appeal to a robust but referentially opaque theory–world relation. The dynamical notion of ‘tracking’ fulfills this promise. I formulate a modified no miracles argument that is liberated from the false dichotomy and show how tracking responds to the modified argument. (shrink)

Amalgamating evidence from heterogeneous sources and across levels of inquiry is becoming increasingly important in many pure and applied sciences. This special issue provides a forum for researchers from diverse scientific and philosophical perspectives to discuss evidence amalgamation, its methodologies, its history, its pitfalls, and its potential. We situate the contributions therein within six themes from the broad literature on this subject: the variety-of-evidence thesis, the philosophy of meta-analysis, the role of robustness/sensitivity analysis for evidence amalgamation, its bearing on questions (...) of extrapolation and external validity of experiments, its connection with theory development, and its interface with causal inference, especially regarding causal theories of cancer. (shrink)

The use of probability theory is widespread in our daily life as well as in scientific theories. In virtually all cases, calculations can be carried out within the framework of classical probability theory. A special exception is given by quantum mechanics, which gives rise to a new probability theory: quantum probability theory. This dissertation deals with the question of how this formalism can be understood from a philosophical and physical perspective. The dissertation is divided into three parts. In the first (...) part, the formalism of quantum probability theory and its relation to quantum mechanics is presented. The second part considers the possibility of reformulating quantum probability theory to embed it within classical probability. Mathematically, this possibility overlaps with the possibility of the existence of hidden variables theories of quantum mechanics: theories that attempt to solve fundamental problems in quantum mechanics by introducing additional physical properties of systems. The conclusion of this part is that, although classical reformulations of quantum probability theory are formally possible, they offer little insight into the formalism of quantum probability theory itself. The third part regards a more direct investigation of quantum probability theory. A reformulation of quantum probability theory is obtained by constructing a quantum logic on the basis of empirical non-probabilistic predictions of quantum mechanics. In this reformulation quantum probability functions are conditional probability functions on an algebra of propositions about measurements and measurement outcomes. (shrink)

Le modèle atomique de Bohr a été l'un des exemples les plus brillants de la méthodologie des programmes de recherche d'Imre Lakatos. Les grandes lignes du programme de recherche de Bohr (Bohr 1913) peuvent être caractérisées par : 1. Le problème initial ; 2. Ses heuristiques négatives et positives ; 3. Les problèmes qu'il a tenté de résoudre au cours du développement ; 4. Son point de dégénérescence (point de saturation) et, enfin, 5. Le programme par lequel il a été (...) remplacé. 10.13140/RG.2.2.21718.68166 . (shrink)

This article examines the problem of the origins of the correspondence principle formulated by Bohr in 1920 and intends to test the correctness of the argument that the essential elements of that principle were already present in the 1913 “trilogy”. In contrast to this point of view, moreover widely shared in the literature, this article argues that it is possible to find a connection between the formulation of the correspondence principle and the assessment that led Bohr to abandon the search (...) for a Planck-type theory. In fact, a thorough examination of Bohr’s works shows that the birth of this principle coincided with the depletion of a research program whose origins may date back to Bohr’s stay at the Rutherford’s laboratory (summer 1912). Finally, this article argues that original program of research was abandoned when it became clear that Planck’s quantum hypothesis for the harmonic oscillator was not an adequate support for the theoretical architecture of atomic physics; namely, there was evidence enough to justify a most drastic conclusion, according to Bohr: “I do not think that a theory of the Planck type can be made logical consistent”. (shrink)

In this article, I evaluate Hartmann and Fitelson’s solution to the Bayesian problem of old evidence by applying it to an early stage in the development of quantum theory. I argue that this case study suggests that whether old evidence is anomalous affects its support for a hypothesis. I introduce and defend two formal assumptions to accommodate this idea. This analysis not only explicates an important historical example, but it also shows that the given solution captures the intuitive importance of (...) “surprising” evidence that has previously been problematic in the context of old evidence. (shrink)

Recent research shows that research programmes (quantitative, qualitative and mixed) in education are not displaced (as suggested by Kuhn) but rather lead to integration. The objective of this study is to present a rationale for mixed methods (integrative) research programs based on contemporary philosophy of science (Lakatos, Giere, Cartwright, Holton, Laudan). This historical reconstruction of episodes from physical science (spanning a period of almost 300 years, 17 th to 20 th century) does not agree with the positivist image of science. (...) Quantitative data (empirical evidence) by itself, does not facilitate progress (despite widespread belief to the contrary), neither in the physical sciences nor in the social sciences (education) A historical reconstruction shows that both Piaget and Pascual-Leone's research programs in cognitive psychology, follow the Galilean idealisation quite closely, similar to the research programs of Newton, Mendeleev, Einstein, Thomson, Rutherford, Millikan and Perl in the physical sciences. This relationship does not imply that researchers in education have to emulate research in the physical sciences. A major argument in favor of mixed methods (integrative) research programs is that it provides a rationale for hypotheses, theories, guiding assumptions and presuppositions to compete and provide alternatives. Similar to the physical sciences, this proliferation of hypotheses leads to controversies and rivalries, and thus facilitates the decision making process of the scientific community. It is concluded that mixed methods research programs (not paradigms) in education can facilitate the construction of robust strategies, provided we let the problem situation (as studied by practicing researchers) decide the methodology. (shrink)

This paper considers the importance of unification in the context of developing scientific theories. I argue that unifying hypotheses are not valuable simply because they are supported by multiple lines of evidence. Instead, they can be valuable because they guide experimental research in different domains in such a way that the results from those experiments inform the scope of the theory being developed. I support this characterization by appealing to the early development of quantum theory. I then draw some comparisons (...) with discussions of robustness reasoning. (shrink)

Policy-makers face an uncertain world. One way of getting a handle on decision-making in such an environment is to rely on evidence. Despite the recent increase in post-fact figures in politics, evidence-based policymaking takes centre stage in policy-setting institutions. Often, however, policy-makers face large volumes of evidence from different sources. Robustness analysis can, prima facie, handle this evidential diversity. Roughly, a hypothesis is supported by robust evidence if the different evidential sources are in agreement. In this thesis, I strengthen the (...) case for the use of robustness analysis in evidence-based policymaking by answering open research questions about this inference technique. First, I argue that existing taxonomies miss a fruitful category of robustness reasoning, that is predictive stability. Second, I claim that derivational robustness analysis – the investigation of whether the results of different models are in agreement – can yield interesting insights even if not the entire relevant model space is covered by available models or if the model results are only partially in agreement. Third, I claim that expert knowledge is necessary to address questions that arise when one applies measurement robustness analysis – the investigation into whether multiple means of measurement yield the same result. Finally, I argue that, in situations where evidence from different measurements is not in agreement, it can be advisable to no longer take all of the evidence into account. This can be done in a rationally defensible way by choosing the most adequate theory or model underlying parts of the evidence set. I discuss examples from climate, medical, and economic policy-making to establish my claims. (shrink)

This paper considers the importance of unification in the context of developing scientific theories. I argue that unifying hypotheses are not valuable simply because they are supported by multiple lines of evidence. Instead, they can be valuable because they guide experimental research in different domains in such a way that the results from those experiments inform the scope of the theory being developed. I support this characterization by appealing to the early development of quantum theory. I then draw some comparisons (...) with discussions of robustness reasoning. (shrink)

El principio de correspondencia y el punto de vista de la complementariedad constituyen los sucesivos ejes alrededor de los cuales gira la interpretación de Bohr de la teoría cuántica. En este trabajo sostenemos que el concepto kantiano de analogía resulta un hilo conductor que permite comprender satisfactoriamente tal desarrollo histórico del pensamiento de Bohr. Mostraremos que el principio de correspondencia guía la búsqueda de analogías en la experiencia, mientras que desde el punto de vista de la complementariedad Bohr establece analogías (...) simbólicas. The principle of correspondence and, later, the viewpoint of complementarity are the axes around which Bohr´s interpretation of quantum theory rotates. In this paper we claim that the Kantian notion of analogy enables a satisfactory understanding of such historical development of Bohr's thought. We shall show that the principle of correspondence guides the search for analogies in experience, while from the viewpoint of complementarity Bohr establishes symbolic analogies. (shrink)

A case study of the development of quantum field theory and of S-matrix theory, from their inceptions to the present, is presented. The descriptions of science given by Kuhn and by Lakatos are compared and contrasted as they apply to this case study. The episodes of the developments of these theories are then considered as candidates for competing research programs in Lakatos' methodology of scientific research programs. Lakatos' scheme provides a reasonable overall description and a plausible assessment of the relative (...) value of these two programs in terms of progressive and degenerating problem shifts. Also discussed are the roles of various types of models as they have been used in these areas of theoretical high-energy physics. (shrink)

A cluster of problems — the “quantum mechanical measurement problem”, the “problem of the reduction of the wave packet”, the “problem of the actualization of potentialities,” and the “Schrödinger Cat problem” — are raised by standard quantum dynamics when certain assumptions are made about the interpretation of the quantum mechanical formalism. Investigators who are unwilling to abandon these assumptions will be motivated to propose modifications of the quantum formalism. Among these, many (including Professor Ghirardi and Professor Pearle) have felt that (...) the most promising locus of modification is quantum dynamics, and in their presentations (this Volume) they have suggested stochastic modifications of the standard deterministic and linear evolution of the quantum state. (shrink)

Niels Bohr’s model of the hydrogen atom is widely cited as an example of an inconsistent scientific theory because of its reliance on classical electrodynamics together with assumptions about interactions between matter and electromagnetic radiation that could not be reconciled with CED. This view of Bohr’s model is controversial, but we believe a recently proposed approach to reasoning with inconsistent commitments offers a promising formal reading of how Bohr’s model worked. In this paper we present this new way of reasoning (...) with inconsistent commitments and compare it with other approaches before applying it to Bohr’s model and offering some suggestions for how it might be extended to account for subsequent developments in old quantum theory. (shrink)

We complete our previous(1, 2) demonstration that there is a family of new solutions to the photon and Dirac equations using spatial and temporal circles and four-vector behaviour of the Dirac bispinor. We analyse one solution for a bound state, which is equivalent to the attractive two-body interaction between a charged point particle and a second, which remains at rest. We show this yields energy and angular momentum eigenvalues that are identical to those found by the usual method of solving (...) of the Dirac equation,(4) including fine structure. We complete our previous derivation(2) of QED from a set of rules for the two-body interaction and generalise these. We show that QED may be decomposed into a two-body interaction at every point in spacetime. (shrink)

Some scientific theories are inconsistent, yet non-trivial and meaningful. How is that possible? The present paper aims to show that we can analyse the inferential use of such theories in terms of consistent compositions of the applications of universal axioms. This technique will be represented by a preferred models semantics, which allows us to accept the instances of universal axioms selectively. For such a semantics to be developed, the framework of partial structures by da Costa and French will be extended (...) by a few elements of the Sneed formalism, also known as the structuralist approach to science. (shrink)

The purpose of this dissertation is to contribute to our understanding of scientific theory pursuit by providing a detailed case study on the development of early quantum theory, from roughly 1900 to 1916. I first elaborate on why this case should be considered an instance of piecemeal pursuit by presenting the historical quantum conjectures that were being used in different contexts. These conjectures gave varied interpretations of quantization. By comparing these conjectures, I identify a general quantum postulate that captures the (...) underlying assumption common to all the cases. I argue that it is possible to consider a general postulate about quantization even when its proper application is ambiguous in a given context, and that the postulate can be separated from different elements of the framework being used to investigate it. I show that the quantum postulate can be deemed promising by analysing the support it gains using a Bayesian framework. I first defend the use of such a framework by considering the purported inconsistencies in Planck's introduction of his quantum conjecture and how we should handle these. I then explicate two cases of support for the postulate. First, I show how we can use a particular solution to the Bayesian problem of old evidence to interpret the support the quantum postulate received by accounting for phenomena that had no previous explanation. Finally, I show that the quantum postulate is also supported by a unification argument, where unification is interpreted as informational relevance between the different domains of inquiry. (shrink)

We present a general classification of the conditions under which cognitive science, concerned, e.g. with decision making, requires the use of quantum theoretical notions. The analysis is done in the frame of the mathematical approach based on the theory of quantum measurements. We stress that quantum effects in cognition can arise only when decisions are made under uncertainty. Conditions for the appearance of quantum interference in cognitive sciences and the conditions when interference cannot arise are formulated.

The correspondence principle states that the quantum system will approach the classical system in high quantum numbers. Indeed, the average of the quantum probability density distribution reflects a classical-like distribution. However, the probability of finding a particle at the node of the wave function is zero. This condition is recognized as the nodal issue. In this paper, we propose a solution for this issue by means of complex quantum random trajectories, which are obtained by solving the stochastic differential equation derived (...) from the optimal guidance law. It turns out that point set A, which is formed by the intersections of complex random trajectories with the real axis, can represent the quantum mechanical compatible distribution of the quantum harmonic oscillator system. Meanwhile, the projections of complex quantum random trajectories on the real axis form point set B that gives a spatial distribution without the appearance of nodes, and approaches the classical compatible distribution in high quantum numbers. Furthermore, the statistical distribution of point set B is verified by the solution of the Fokker–Planck equation. (shrink)

The paper offers a historical overview of Einstein's oscillating attitude towards a "phenomenological" and "dynamical" treatment of rods and clocks in relativity theory. Contrary to what it has been usually claimed in recent literature, it is argued that this distinction should not be understood in the framework of opposition between principle and constructive theories. In particular Einstein does not seem to have plead for a "dynamical" explanation for the phenomenon rods contraction and clock dilation which was initially described only "kinematically". (...) On the contrary textual evidence shows that, according to Einstein, a realistic microscopic model of rods and clocks was needed to account for the very existence of measuring devices of "identical construction" which always measure the same unit of time and the same unit of length. In fact, it will be shown that the empirical meaningfulness of both relativity theories depends on what, following Max Born, one might call the "principle of the physical identity of the units of measure". In the attempt to justify the validity of such principle, Einstein was forced by different interlocutors, in particular Hermann Weyl and Wolfgang Pauli, to deal with the genuine epistemological, rather then physical question whether a theory should be able or not to described the material devices that serve to its own verification. (shrink)

ArgumentThe use of diagrams is pervasive in theoretical physics. Together with mathematical formulae and natural language, diagrams play a major role in theoretical modeling. They enrich the expressive power of physicists and help them to explore new theoretical ideas. Diagrams are not only heuristic or pedagogical tools, but they are also tools that enable developing the content of models into novel implications.

In line with the semantic conception of scientific theories, I develop an account of the intertheory relation of comparative structural similarity. I argue that this relation is useful in explaining the concept of verisimilitude and I support this contention with a concrete historical example. Finally, I defend this relation against the familiar charge that the concept of similarity is insufficiently objective.

We have shown in a previous paper that the Dirac bispinor can vary like a four-vector and that Quantum Electrodynamics can be reproduced with this form of behaviour. In Part I of this paper, we show that QED with the same transformational behaviour also holds in an alternative space we call M-space. We use the four-vector behaviour to model the two-body interaction in M and show that this has similar physical properties to the usual model in L which it predicts. (...) In Part II of this paper we use M-space to show that QED can be reduced to two simple rules for a two-body interaction. (shrink)