In 1952 Bohm presented a theory about non-relativistic point-particles that move deterministically along trajectories and showed how it reproduces the predictions of standard quantum theory. This theory was actually presented before by de Broglie in 1926, but Bohm’s particular formulation of the theory inspired Epstein to come up with a different trajectory model. The aim of this paper is to examine the empirical predictions of this model. It is found that the trajectories in this model are in general very different (...) from those in the de Broglie-Bohm theory. In certain cases they even seem bizarre and rather unphysical. Nevertheless, it is argued that the model seems to reproduce the predictions of standard quantum theory (just as the de Broglie-Bohm theory). (shrink)

Here I explore a novel no-collapse interpretation of quantum mechanics that combines aspects of two familiar and well-developed alternatives, Bohmian mechanics and the many-worlds interpretation. Despite reproducing the empirical predictions of quantum mechanics, the theory looks surprisingly classical. All there is at the fundamental level are particles interacting via Newtonian forces. There is no wave function. However, there are many worlds.

Until recently Jeffrey Bub and Itamar Pitowsky, in the framework of an information-theoretic view of quantum mechanics, claimed first that to the measurement problem in its ordinary formulation there correspond in effect two measurement problems (simply called the big and the small measurement problems), with a different degree of relevance and, second, that the analysis of a quantum measurement is a problem only if other assumptions – taken by Pitowsky and Bub to be unnecessary ‘dogmas’ – are assumed. Here I (...) critically discuss this unconventional stance on the measurement problem and argue that the Bub-Pitowsky arguments are inconclusive, mainly because they rely on an unwarranted extension to the quantum realm of a distinction concerning the foundations of special relativity which is in itself rather controversial. (shrink)

In this paper we analyze the relation between the notion of typicality and the notion of probability and the related question of how the choice of measure in deterministic theories in physics may be justified. Recently it has been argued that although the notion of typicality is not a probabilistic notion, it plays a crucial role in underwriting probabilistic statements in classical statistical mechanics and in Bohm’s theory. We argue that even in theories with deterministic dynamics, like classical statistical mechanics (...) and Bohm’s theory, the notion of probability can be understood as fundamentally objective, and that it is the notion of probability rather than typicality that may have an explanatory value. (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)

Bohmian mechanics, which is also called the de Broglie-Bohm theory, the pilot-wave model, and the causal interpretation of quantum mechanics, is a version of quantum theory discovered by Louis de Broglie in 1927 and rediscovered by David Bohm in 1952. It is the simplest example of what is often called a hidden variables interpretation of quantum mechanics. In Bohmian mechanics a system of particles is described in part by its wave function, evolving, as usual, according to Schrödinger's equation. However, the (...) wave function provides only a partial description of the system. This description is completed by the specification of the actual positions of the particles. The latter evolve according to the.. (shrink)

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)

By means of the examples of classical and Bohmian quantum mechanics, we illustrate the well-known ideas of Boltzmann as to how one gets from laws defined for the universe as a whole to dynamical relations describing the evolution of subsystems. We explain how probabilities enter into this process, what quantum and classical probabilities have in common and where exactly their difference lies.

What becomes of our clearest theories of explanation, when faced with the unpalatable quantum phenomena that seem to undermine the direct conceptual connection between the fundamental material entities and the self-standing material objects of everyday parlance? The general explanatory theory advocates unification of explanatory concepts with everyday discourse, identification of essentially similar characteristics between direct experience and the hypothesised explanatory ontology, and a conceptualisation of phenomena in terms of objects enduring causally regulated change. On the other hand quantum theory feeds (...) antirealist suspicions about the worth of realist explanatory endeavour with examples of phenomena in which the structure of material separation and individuation based on spatial extension is insufficient for construction of deeper explanatory narratives. An example from history of science, that of Newton’s law-constitutive definition of objects in response to D escartes problem of bodies is used to suggest a possible strategy for explanations unifying the quantum and common-sense conceptual domains, provided the anti-realist challenge to such enterprise is read as questioning the epistemological justification of interpretation of experience in both cases.Što se događa s najjasnijim dostupnim teorijama objašnjenja kada se suoče s problematičnim kvantnim pojavama koje naizgled potkopavaju neposrednu konceptualnu poveznicu između fundamentalnih materijalnih entiteta i samoopstojnih materijalnih predmeta iz svakodnevnog govora? Opća teorija objašnjenja preporuča objedinjenje teoretskih eksplanatornih pojmova sa svakodnevnim govorom, određenje esencijalno sličnih karakteristika između neposrednog iskustva i hipotetske eksplanatorne ontologije te konceptualizaciju pojava kroz predmete koji istraju kroz uzročno regulirane promjene. S druge strane, kvantna teorija potkrjepljuje antirealistične sumnje o valjanosti eksplanatornog nastojanja realizma primjerima pojava u kojima je struktura materijalne razdvojenosti i individuacije temeljene na prostornoj protežnosti nedovoljna za izgradnju dubljih eksplanatornih narativa. Primjerom iz povijesti znanosti, Newtonovom definicijom predmeta temeljenom na zakonima kao odgovorom na Descartesov problem materijalnih tijela, daje se moguća strategija izgradnje objašnjenja koja objedinjuju kvantne i “zdravorazumske” konceptualne domene, ukoliko se antirealistična kritika te izgradnje u oba slučaja shvati kao propitivanje epistemološkog opravdanja tumačenja iskustva. (shrink)