What does it mean for a hypothesis to be ad hoc? One prominent account has it that ad hoc hypotheses have no independent empirical support. Others have viewed ad hoc judgements as subjective. Here I critically review both of these views and defend my own Coherentist Conception of Ad hocness by working out its conceptual and descriptive attractions.

The purpose of this contribution is to examine the current state of the de Broglie-Bohm theory (dBB) in light of Bohm’s vision as he explicitly set it out in his book Quantum theory [In Bohm, D., Quantum theory, Courier corporation, (1961b)]. In particular, two programmes that differ in many crucial respects are currently being pursued. On the one hand, the Bohmian mechanics school, founded by Dürr Goldstein and Zanghì, considers the theory to be Galilean invariant, regards particles’ motion as determined (...) by a nomological entity, the universal wave function, upholds the quantum equilibrium hypothesis and explains probabilities in terms of typicality. On the other hand, the Pilot-wave school advocated by Valentini considers the theory to be based on Aristotelian dynamics, regards the wave function as a physical field displaying a contingent nature, and explains quantum equilibrium as the result of a process of relaxation from quantum non-equilibrium. Looking at Bohm’s work [In Bohm, D., Quantum theory, Courier corporation, (1961b)], it is clear that his intention was to construct a theory that was empirically different from standard quantum mechanics, so that it would be testable and falsifiable. Only this way could he defend dBB from the criticism that accused the theory of being 'metaphysical'. These methodological concerns about the falsifiability of the theory constitute, in my opinion, a strong reason for regarding Valentini's programme as methodologically valuable, even if it might turn out to be wrong. Indeed, the programme of the Pilot-wave school aims to be falsifiable with respect to standard quantum mechanics and can in principle defend the empirical status of particle trajectories. (shrink)

In der vorliegenden Arbeit wird über die verschiedenen Aspekte der sogenannten FitzGerald-Lorentz-Kontraktion berichtet. Nach einem kurzen Abriß der Entwicklung der Ätherkonzeption wird eine Beschreibung des Michelson-Morley Versuchs gegeben und seine Rolle in der Entstehungsgeschichte der speziellen Relativitätstheorie diskutiert. Anschließend wird die Kontraktionshypothese vorgestellt und die Frage erörtert, ob die Kontraktion „wirklich“ oder nur „scheinbar“ ist. Einige Gedankenexperimente werden vorgestellt, die zeigen, daß die Kontraktion bewegter Körper kein bloßer Schein ist. Ferner wird die noch bei Einstein unklare Beantwortung nach der Frage (...) der Sichtbarkeit der Längenkontraktion durch die Analyse der Begriffe „Beobachten“ und „Sehen“ aufgehellt. Abschließend wird auf die Frage nach der Falsifizierbarkeit der Kontraktionshypothese eingegangen, die von Popper aufgeworfen wurde. (shrink)

The Einsteinian revolution, which began around 1905, was one of the most remarkable in the history of physics. It replaced Newtonian mechanics, which had been accepted as completely correct for nearly 200 years, by the special and general theories of relativity. It also eliminated the aether, which had dominated physics throughout the nineteenth century. This paper poses the question of why this momentous scientific revolution began. The suggested answer is in terms of the remarkable series of discoveries and inventions which (...) occurred in the preceding decade and which were the result of technological developments in instrumentation. The paper gives a survey of these inventions and discoveries, which include X-rays, radioactivity, the electron, wireless transmissions across the Atlantic and the patenting of the first thermionic valve. An attempt is then made to show that it was these developments, which gave rise to special relativity. (shrink)

I argue that to the extent to which philosophical theories of objective probability have offered theoretically adequateconceptions of objective probability (in connection with such desiderata as causal and explanatory significance, applicability to single cases, etc.), they have failed to satisfy amethodological standard — roughly, a requirement to the effect that the conception offered be specified with the precision appropriate for a physical interpretation of an abstract formal calculus and be fully explicated in terms of concepts, objects or phenomena understood independently (...) of the idea of physical probability. The significance of this, and of the suggested methodological standard, is then briefly discussed. (shrink)

In this paper I argue that the case of Einstein׳s special relativity vs. Hendrik Lorentz׳s ether theory can be decided in terms of empirical evidence, in spite of the predictive equivalence between the theories. In the historical and philosophical literature this case has been typically addressed focusing on non-empirical features. I claim that non-empirical features are not enough to provide a fully objective and uniquely determined choice in instances of empirical equivalence. However, I argue that if we consider arguments proposed (...) by Richard Boyd, and by Larry Laudan and Jarret Leplin, a choice based on non-entailed empirical evidence favoring Einstein׳s theory can be made. (shrink)