4,892 research outputs found
Quantum Theory and Determinism
Historically, appearance of the quantum theory led to a prevailing view that
Nature is indeterministic. The arguments for the indeterminism and proposals
for indeterministic and deterministic approaches are reviewed. These include
collapse theories, Bohmian Mechanics and the many-worlds interpretation. It is
argued that ontic interpretations of the quantum wave function provide simpler
and clearer physical explanation and that the many-worlds interpretation is the
most attractive since it provides a deterministic and local theory for our
physical Universe explaining the illusion of randomness and nonlocality in the
world we experience.Comment: Some references updated. Published online in Quantum Studies:
Mathematics and Foundation
Quantum Mechanics on Spacetime I: Spacetime State Realism
What ontology does realism about the quantum state suggest? The main extant
view in contemporary philosophy of physics is wave-function realism. We
elaborate the sense in which wave-function realism does provide an ontological
picture; and defend it from certain objections that have been raised against
it. However, there are good reasons to be dissatisfied with wave-function
realism, as we go on to elaborate. This motivates the development of an
opposing picture: what we call spacetime state realism; a view which takes the
states associated to spacetime regions as fundamental. This approach enjoys a
number of beneficial features, although, unlike wave-function realism, it
involves non-separability at the level of fundamental ontology. We investigate
the pros and cons of this non-separability, arguing that it is a quite
acceptable feature; even one which proves fruitful in the context of
relativistic covariance. A companion paper discusses the prospects for
combining a spacetime-based ontology with separability, along lines suggested
by Deutsch and HaydenComment: LaTeX; 29 pages, 1 Fig. Forthcoming in the British Journal for the
Philosophy of Scienc
The physics and metaphysics of primitive stuff
The paper sets out a primitive ontology of the natural world in terms of
primitive stuff, that is, stuff that has as such no physical properties at all,
but that is not a bare substratum either, being individuated by metrical
relations. We focus on quantum physics and employ identity-based Bohmian
mechanics to illustrate this view, but point out that it applies all over
physics. Properties then enter into the picture exclusively through the role
that they play for the dynamics of the primitive stuff. We show that such
properties can be local (classical mechanics), as well as holistic (quantum
mechanics), and discuss two metaphysical options to conceive them, namely
Humeanism and modal realism in the guise of dispositionalism
Ontological aspects of the Casimir Effect
The role of the vacuum, in the Casimir Effect, is a matter of some dispute:
the Casimir force has been variously described as a phenomenon resulting "from
the alteration, by the boundaries, of the zero-point electromagnetic energy",
or a "Van der Waals force between the metal plates" that can be "computed
without reference to zero point energies". Neither of these descriptions are
grounded in a consistently quantum mechanical treatment of matter interacting
with the electromagnetic field. However, the Casimir Effect has been
canonically described within the framework of macroscopic quantum
electrodynamics. On this account, the force is seen to arise due to the
coupling of fluctuating currents to the zero-point radiation, and it is in this
restricted sense that the phenomenon requires the existence of zero-point
fields. The conflicting descriptions of the Casimir Effect, on the other hand,
appear to arise from inadequate ontologies in which an unwarranted metaphysical
priority is assigned either to the matter or the fields. Such ontological
errors may have a direct bearing on the problem of the cosmological constant
and the correct prediction of the Casimir force in a state of thermal
equilibrium.Comment: 6 page
Interdisciplinary perspectives on the development, integration and application of cognitive ontologies
We discuss recent progress in the development of cognitive ontologies and summarize three challenges in the coordinated development and application of these resources. Challenge 1 is to adopt a standardized definition for cognitive processes. We describe three possibilities and recommend one that is consistent with the standard view in cognitive and biomedical sciences. Challenge 2 is harmonization. Gaps and conflicts in representation must be resolved so that these resources can be combined for mark-up and interpretation of multi-modal data. Finally, Challenge 3 is to test the utility of these resources for large-scale annotation of data, search and query, and knowledge discovery and integration. As term definitions are tested and revised, harmonization should enable coordinated updates across ontologies. However, the true test of these definitions will be in their community-wide adoption which will test whether they support valid inferences about psychological and neuroscientific data
Taking Heisenberg's Potentia Seriously
It is argued that quantum theory is best understood as requiring an
ontological duality of res extensa and res potentia, where the latter is
understood per Heisenberg's original proposal, and the former is roughly
equivalent to Descartes' 'extended substance.' However, this is not a dualism
of mutually exclusive substances in the classical Cartesian sense, and
therefore does not inherit the infamous 'mind-body' problem. Rather, res
potentia and res extensa are proposed as mutually implicative ontological
extants that serve to explain the key conceptual challenges of quantum theory;
in particular, nonlocality, entanglement, null measurements, and wave function
collapse. It is shown that a natural account of these quantum perplexities
emerges, along with a need to reassess our usual ontological commitments
involving the nature of space and time.Comment: Final version, to appear in International Journal of Quantum
Foundation
An Introduction to Ontology
Analytical philosophy of the last one hundred years has been heavily influenced by a doctrine to the effect that one can arrive at a correct ontology by paying attention to certain superficial (syntactic) features of first-order predicate logic as conceived by Frege and Russell. More specifically, it is a doctrine to the effect that the key to the ontological structure of reality is captured syntactically in the âFaâ (or, in more sophisticated versions, in the âRabâ) of first-order logic, where âFâ stands for what is general in reality and âaâ for what is individual. Hence âf(a)ntologyâ. Because predicate logic has exactly two syntactically different kinds of referring expressionsââFâ, âGâ, âRâ, etc., and âaâ, âbâ, âcâ, etc.âso reality must consist of exactly two correspondingly different kinds of entity: the general (properties, concepts) and the particular (things, objects), the relation between these two kinds of entity being revealed in the predicate-argument structure of atomic formulas in first-order logic
Scientific Realism without the Wave-Function: An Example of Naturalized Quantum Metaphysics
Scientific realism is the view that our best scientific theories can be regarded as (approximately) true. This is connected with the view that science, physics in particular, and metaphysics could (and should) inform one another: on the one hand, science tells us what the world is like, and on the other hand, metaphysical principles allow us to select between the various possible theories which are underdetermined by the data. Nonetheless, quantum mechanics has always been regarded as, at best, puzzling, if not contradictory. As such, it has been considered for a long time at odds with scientific realism, and thus a naturalized quantum metaphysics was deemed impossible. Luckily, now we have many quantum theories compatible with a realist interpretation. However, scientific realists assumed that the wave-function, regarded as the principal ingredient of quantum theories, had to represent a physical entity, and because of this they struggled with quantum superpositions. In this paper I discuss a particular approach which makes quantum mechanics compatible with scientific realism without doing that. In this approach, the wave-function does not represent matter which is instead represented by some spatio-temporal entity dubbed the primitive ontology: point-particles, continuous matter fields, space-time events. I argue how within this framework one develops a distinctive theory-construction schema, which allows to perform a more informed theory evaluation by analyzing the various ingredients of the approach and their inter-relations
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