The paper takes up Bell's “Everett theory” and develops it further. The resulting theory is about the system of all particles in the universe, each located in ordinary, 3-dimensional space. This many-particle system as a whole performs random jumps through 3N-dimensional configuration space – hence “Tychistic Bohmian Mechanics”. The distribution of its spontaneous localisations in configuration space is given by the Born Rule probability measure for the universal wavefunction. Contra Bell, the theory is argued to satisfy the minimal desiderata for (...) a Bohmian theory within the Primitive Ontology framework. TBM's formalism is that of ordinary Bohmian Mechanics, without the postulate of continuous particle trajectories and their deterministic dynamics. This “rump formalism” receives, however, a different interpretation. We defend TBM as an empirically adequate and coherent quantum theory. Objections voiced by Bell and Maudlin are rebutted. The “for all practical purposes”-classical, Everettian worlds exist sequentially in TBM. In a temporally coarse-grained sense, they quasi-persist. By contrast, the individual particles themselves cease to persist. (shrink)

This thesis develops a detailed account of the emergence of for all practical purposes continuous, quasi-classical world histories from the discontinuous, stochastic micro dynamics of Minimal Bohmian Mechanics (MBM). MBM is a non-relativistic quantum theory. It results from excising the guiding equation from standard Bohmian Mechanics (BM) and reinterpreting the quantum equilibrium hypothesis as a stochastic guidance law for the random actualization of configurations of Bohmian particles. On MBM, there are no continuous trajectories linking up individual configurations. Instead, individual configurations (...) are actualized independently of each other, carving out the decoherence-induced branching structure of the universal wave function. Yet, by contrast to the Everett interpretation, branches of the universal wave function are not actualized in parallel, i.e. all at the same time. Rather, world branches, on MBM, are actualized sequentially. -/- For an introduction to MBM, the transition from BM to MBM is described, and their empirical equivalence is established. I present the conditions under which MBM can be classified as a primitive ontology (PO) theory, regarded as crucial for the acceptance of a theory as Bohmian by many proponents of BM. While rendering MBM compatible with the PO approach, it must not fall prey to the problem of communication, arising from the two-space reading of BM. -/- The issue of temporal solipsism, identified by Bell as a serious problem for his “Everett (?) theory” – the historic predecessor of MBM – is discussed. I argue that Barbour’s time capsule approach does not provide a satisfactory solution. In particular, his adopting a more than minimal psychophysical parallelism between brain processes and experience of macroscopic change is argued to be reasonable in light of our current best neuroscience, yet problematic for theories relying solely on time capsules, understood as highly structured, individual, internally static configurations. As a solution, I introduce worlds, and world histories, as key concepts in providing a link between MBM’s micro dynamics and macroscopic phenomena. Worlds, other than time capsules, are coarse-grained regions in phase- or configuration space, defined as sets of possible micro states satisfying a relation of sufficient similarity from a macroscopic perspective, with respect to a given micro state. Hence, worlds may overlap. -/- I argue that worlds thus construed are a reasonable option for replacing the disjoint macro regions of phase space, resulting from the usual way of partitioning phase space in the standard framework of Boltzmannian statistical mechanics. This move solves the issue of discontinuous change of macro variables upon the micro state crossing the boundary between different macro regions. -/- I adapt this move for MBM’s discontinuous micro dynamics in configuration space. Issues revolving around the microscopic-macroscopic distinction, particle identity, impenetrability and haecceity in light of the desideratum of particle number conservation, etc., are discussed. I provide a detailed explanation of how overlapping worlds in MBM form world histories, thereby linking up macroscopically distinct worlds. Thus, the problem of temporal solipsism is resolved in a way that is compatible with a more than minimal psychophysical parallelism. (shrink)

[ENGLISH] The present article is a contribution to the development of metrological structural realism. This position of philosophy of science goes back to Matthias Neuber, who introduces it as a third variation of the main structural realisms: epistemic structural realism and ontic structural realism. Here, Neuber attempts to tackle the problems of OSR and ESR while preserving their respective strengths. Of central importance to his approach, are the concepts of invariance, structure and, especially, measurement. Starting from Eino Kaila’s „non-linguistic, realist (...) account of logical empricism“, the present article investigates the necessity of yet another position of structural realism. The established structural realisms are examined for their strengths and weaknesses. Afterwards, the requirements on MSR are formulated in a way that extends beyond Neuber’s account. These requirements are of ontological, epistemological and metrological nature. -/- [DEUTSCH] Der vorliegende Aufsatz ist ein Beitrag zur Entwicklung des Metrologischen Strukturenrealismus. Diese Wissenschaftstheoretische Position geht auf Matthias Neuber zurück, der sie als dritte Spielart zwischen den großen Strukturenrealismen – dem Epistemischen Strukturenrealismus und dem Ontischen Strukturenrealismus – ansiedelt. Neuber versucht, die wissenschaftstheoretischen Probleme von ESR und OSR anzugehen, gleichzeitig aber ihre jeweiligen Stärken beizubehalten. Dabei sind die Konzepte der Invarianz, der Struktur und besonders der Messung von zentraler Bedeutung. Ausgehend von Eino Kailas „non-linguistic, realist account of logical empiricism“ untersucht der vorliegende Aufsatz die Notwendigkeit einer weiteren strukturenrealistischen Position. Dazu werden die etablierten Strukturenrealismen auf ihre Stärken und Schwächen hin untersucht. Es folgt eine Ausformulierung der Forderungen an den MSR, die über die Darstellung bei Neuber hinaus geht. Diese Forderungen sind ontologischer, epistemischer und metrologischer Natur. (shrink)