42 research outputs found
The One, the Many, and the Quantum
The problem of understanding quantum mechanics is in large measure the
problem of finding appropriate ways of thinking about the spatial and temporal
aspects of the physical world. The standard, substantival, set-theoretic
conception of space is inconsistent with quantum mechanics, and so is the
doctrine of local realism, the principle of local causality, and the
mathematical physicist's golden calf, determinism. The said problem is made
intractable by our obtruding onto the physical world a theoretical framework
that is more detailed than the physical world. This framework portraits space
and time as infinitely and intrinsically differentiated, whereas the physical
world is only finitely differentiated spacewise and timewise, namely to the
extent that spatiotemporal relations and distinctions are warranted by facts.
This has the following consequences: (i) The contingent properties of the
physical world, including the times at which they are possessed, are indefinite
and extrinsic. (ii) We cannot think of reality as being built "from the bottom
up", out of locally instantiated physical properties. Instead we must conceive
of the physical world as being built "from the top down": By entering into a
multitude of spatial relations with itself, "existence itself" takes on both
the aspect of a spatially differentiated world and the aspect of a multiplicity
of formless relata, the fundamental particles. At the root of our
interpretational difficulties is the "cookie cutter paradigm", according to
which the world's synchronic multiplicity is founded on the introduction of
surfaces that carve up space in the manner of three-dimensional cookie cutters.
The neurophysiological underpinnings of this insidious notion are discussed.Comment: 47 pages, LaTeX2e with epsfig (2 figures
Two theories of decoherence
Theories of decoherence come in two flavors---Platonic and Aristotelian.
Platonists grant ontological primacy to the concepts and mathematical symbols
by which we describe or comprehend the physical world. Aristotelians grant it
to the physical world. The significance one attaches to the phenomenon of
decoherence depends on the school to which one belongs. The debate about the
significance of quantum states has for the most part been carried on between
Platonists and Kantians, who advocate an epistemic interpretation, with
Aristotelians caught in the crossfire. For the latter, quantum states are
neither states of Nature nor states of knowledge. The real issue is not the
kind of reality that we should attribute to quantum states but the reality of
the spatial and temporal distinctions that we make. Once this is recognized,
the necessity of attributing ontological primacy to facts becomes obvious, the
Platonic stance becomes inconsistent, and the Kantian point of view becomes
unnecessarily restrictive and unilluminating.Comment: 12 pages, LaTeX2
A space for the quantum world
Epistemic interpretations of quantum mechanics fail to address the puzzle
posed by the occurrence of probabilities in a fundamental physical theory. This
is a puzzle about the physical world, not a puzzle about our relation to the
physical world. Its solution requires a new concept of physical space,
presented in this article. An examination of how the mind and the brain
construct the phenomenal world reveals the psychological and neurobiological
reasons why we think about space in ways that are inadequate to the physical
world. The resulting notion that space is an intrinsically partitioned expanse
has up to now stood in the way of a consistent ontological interpretation.Comment: 11 pages, LaTeX2
"B" is for Bohr
It is suggested that the "B" in QBism rightfully stands for Bohr. The paper
begins by explaining why Bohr seems obscure to most physicists. Having
identified the contextuality of physical quantities as Bohr's essential
contribution to Kant's theory of science, it outlines the latter, its proper
contextuality (human experience), and its decontextualization. In order to
preserve the decontextualization achieved by Kant's theory, Bohr seized on
quantum phenomena as the principal referents of atomic physics, all the while
keeping the universal context of human experience at the center of his
philosophy. QBism, through its emphasis on the individual experiencing subject,
brings home the intersubjective constitution of objectivity more forcefully
than Bohr ever did. If measurements are irreversible and outcomes definite, it
is because the experiences of each subject are irreversible and definite.
Bohr's insights, on the other hand, are exceedingly useful in clarifying the
QBist position, attenuating its excesses, and enhancing its internal
consistency.Comment: 38 pages, to appear in the combined Proceedings of the Workshops on
Meaning and Structure of Quantum Mechanics at Buenos Aires (2016 and 2019
The Pondicherry interpretation of quantum mechanics
This article presents a novel interpretation of quantum mechanics. It extends
the meaning of ``measurement'' to include all property-indicating facts.
Intrinsically space is undifferentiated: there are no points on which a world
of locally instantiated physical properties could be built. Instead, reality is
built on facts, in the sense that the properties of things are extrinsic, or
supervenient on property-indicating facts. The actual extent to which the world
is spatially and temporally differentiated (that is, the extent to which
spatiotemporal relations and distinctions are warranted by the facts) is
necessarily limited. Notwithstanding that the state vector does nothing but
assign probabilities, quantum mechanics affords a complete understanding of the
actual world. If there is anything that is incomplete, it is the actual world,
but its incompleteness exists only in relation to a conceptual framework that
is more detailed than the actual world. Two deep-seated misconceptions are
responsible for the interpretational difficulties associated with quantum
mechanics: the notion that the spatial and temporal aspects of the world are
adequately represented by sets with the cardinality of the real numbers, and
the notion of an instantaneous state that evolves in time. The latter is an
unwarranted (in fact, incoherent) projection of our apparent ``motion in time''
into the world of physics. Equally unwarranted, at bottom, is the use of causal
concepts. There nevertheless exists a ``classical'' domain in which language
suggestive of nomological necessity may be used. Quantum mechanics not only is
strictly consistent with the existence of this domain but also presupposes it
in several ways.Comment: TeX, 38 pages, forthcoming in American Journal of Physics under the
title ``What quantum mechanics is trying to tell us'', v2: revised
submission, v3: changes in proo
Unveiled reality: comment on d'Espagnat's note on measurement
According to d'Espagnat we must choose between nonlinear breaks in quantum
state evolution and weak objectivity. In this comment it is shown that this
choice is forced on us by an inconsistent pseudo-realistic interpretation of
quantum states. A strongly objective one-world interpretation of linear quantum
mechanics is presented. It is argued that the weak objectivity favored by
d'Espagnat is, in fact, inconsistent with quantum mechanics.Comment: Comment on quant-ph/0101141, 13 pages, LaTeX2
Is the end in sight for theoretical pseudophysics?
The question of what ontological message (if any) is encoded in the formalism
of contemporary physics is, to say the least, controversial. The reasons for
this state of affairs are psychological and neurobiological. The processes by
which the visual world is constructed by our minds, predispose us towards
concepts of space, time, and substance that are inconsistent with the
spatiotemporal and substantial aspects of the quantum world. In the first part
of this chapter, the latter are extracted from the quantum formalism. The
nature of a world that is fundamentally and irreducibly described by a
probability algorithm is determined. The neurobiological processes responsible
for the mismatch between our "natural" concepts of space, time, and substance
and the corresponding aspects of the quantum world are discussed in the second
part. These natural concepts give rise to pseudoproblems that foil our attempts
to make ontological sense of quantum mechanics. If certain psychologically
motivated but physically unwarranted assumptions are discarded (in particular
our dogged insistence on obtruding upon the quantum world the intrinsically and
completely differentiated spatiotemporal background of classical physics), we
are in a position to see why our fundamental physical theory is a probability
algorithm, and to solve the remaining interpretational problems.Comment: To appear in a volume edited by V. Krasnoholovets and F. Columbus and
published by Nova Science; 26 page
Reflections on the Spatiotemporal Aspects of the Quantum World
The proper resolution of the so-called measurement problem requires a
"top-down" conception of the quantum world that is opposed to the usual
"bottom-up" conception, which builds on an intrinsically and maximally
differentiated manifold. The key to that problem is that the fuzziness of a
variable can manifest itself only to the extent that less fuzzy variables
exist. Inasmuch as there is nothing less fuzzy than the metric, this argues
against a quantum-gravity phenomenology and suggests that a quantum theory of
gravity is something of a contradiction in terms - a theory that would make it
possible to investigate the physics on scales that do not exist, or to study
the physical consequences of a fuzziness that has no physical consequences,
other than providing a natural cutoff for the quantum field theories of
particle physics.Comment: Invited talk at the First Meeting on the Interface of Gravitational
and Quantum Realms held at IUCAA, Pune (India), December 17--21, 2001. To
appear in Mod. Phys. Lett. A. 17 pages. LaTeX2
The Quantum Mechanics of Being and Its Manifestation
How can quantum mechanics be (i) the fundamental theoretical framework of
contemporary physics and (ii) a probability calculus that presupposes the
events to which, and on the basis of which, it assigns probabilities? The
question is answered without invoking knowledge or observers, by interpreting
the necessary distinction between two kinds of physical quantities -
unconditionally definite quantities and quantities that have values only if
they are measured - as a distinction between the manifested world and its
manifestation.Comment: Published (without the Appendix) in Cosmology (Vol. 24, April 2,
2016): http://cosmology.com/ConsciousnessUniverse3.html. While the published
paper touches on various ways in which quantum mechanics does not have to do
with consciousness, the Appendix concerns what quantum mechanics has to do
with consciousness. 9 pages, 0 figures, PD
Why the wave function, of all things?
There are reasons to doubt that making sense of the wave function (other than
as a probability algorithm) will help with the project of making sense of
quantum mechanics. The consistency of the quantum-mechanical correlation laws
with the existence of their correlata is demonstrated. The demonstration makes
use of the fact (which is implied by the indeterminacy principle) that physical
space is not partitioned "all the way down," and it requires that the
eigenvalue-eigenstate link be replaced by a different interpretive principle,
whose implications are explored.Comment: 12 pages, contribution to an online workshop on the meaning of the
wave function, slightly revise