Philosophy of Physics

The Stoic Anomaly: An Inquiry into Some Possible Semitic Components in Stoic Logic and Physics (Spanish)

by Carlos Segovia

"La anomalía estoica: En torno a los posibles componentes semíticos de la lógica y la física estoicas," Paideia 89 (2010) 295-307.

1. Introducción
2. La anomalía lingüístico-temporal (sobre la relativa indistinción del presente y el futuro en... more 1. Introducción
2. La anomalía lingüístico-temporal (sobre la relativa indistinción del presente y el futuro en el estoicismo)
3. La anomalía ontológica (sobre la supresión del verbo "ser" en la física estoica)
4. La anomalía lógica (sobre la supresión de la cópula verbal en la lógica estoica)
5. A modo de conclusión

Reconsidering the Relative State Interpretation

by Emre Keskin

Presented at FPA 2011

In a recent paper, Brett Bevers (2011) has presented a reconstruction of Everett’s relative state interpretation of... more In a recent paper, Brett Bevers (2011) has presented a reconstruction of Everett’s relative state interpretation of quantum mechanics. Compared to the now fashionable decoherence reading, Bevers has taken a different approach to interpreting Everett. He argues that Everett’s original account does not require auxiliary assumptions or mechanisms to overcome the quantum measurement problem.
I argue that even though this is a novel way of interpreting what Everett had in mind and that, prima facie, it might seem to overcome the classical problems associated with the many worlds interpretation (e.g. the preferred basis problem), this reconstruction cannot save the Everettian approach from being a kind of hidden variable theory. I will show that John S. Bell’s insight into the original Everett project, namely that it is nothing other than a hidden variable theory, can be extended to this most recent interpretation. In section two, I will give an account of Everett’s original proposal. In section three, I give an overview of Bell’s objections to that project. I will introduce Bevers’ reconstruction of the original Everett in section four. Finally, I will argue that one consequence of my conclusion is that the reconstruction cannot be compatible with a future physics.

A stronger Bell argument for quantum non-locality

by Paul Naeger

pre-print

It is widely accepted that the violation of Bell inequalities excludes local theories of the quantum realm. In this... more It is widely accepted that the violation of Bell inequalities excludes local theories of the quantum realm. In this paper I present a stronger Bell argument which even forbids certain non-local theories. The remaining non-local theories, which can violate Bell inequalities, are characterised by the fact that at least one of the outcomes in some sense probabilistically depends both on its distant as well as on its local parameter. While this is not to say that parameter dependence in the usual sense necessarily holds, it shows that the received analysis of quantum non-locality as “outcome dependence or parameter dependence” is deeply misleading about what the violation of Bell inequalities implies.

Derivation of the Meaning of the Wave Function

by Shan Gao

Draft Version

We show that the physical meaning of the wave function can be derived based on the established parts of quantum... more We show that the physical meaning of the wave function can be derived based on the established parts of quantum mechanics. It turns out that the wave function represents the state of random discontinuous motion of particles, and its modulus square determines the probability density of the particles appearing in certain positions in space.

Comment on "How to protect the interpretation of the wave function against protective measurements" by Jos Uffink

by Shan Gao

Draft Version

It is shown that Uffink's attempt to protect the interpretation of the wave function against protective measurements... more It is shown that Uffink's attempt to protect the interpretation of the wave function against protective measurements fails due to several errors in his arguments.

Problems of the De Broglie-Bohm Theory

by Shan Gao

Draft Version

It is shown that the de Broglie-Bohm theory has a potential problem concerning the mass and charge distributions of a... more It is shown that the de Broglie-Bohm theory has a potential problem concerning the mass and charge distributions of a quantum system such as an electron. According to the de Broglie-Bohm theory, the mass and charge of an electron are localized in a position where its Bohmian particle is. However, protective measurement indicates that they are not localized in one position but distributed throughout space, and the mass and charge density of the electron in each position is proportional to the modulus square of its wave function there.

An exceptionally simple argument against the many-worlds interpretation

by Shan Gao

Draft Version

It is shown that the components of the wave function of a measuring device, each of which represents a definite... more It is shown that the components of the wave function of a measuring device, each of which represents a definite measurement result, do not correspond to many worlds as assumed by the many-worlds interpretation, because all components of the superposed wave function can be observed in our world by protective measurement, and they all exist in one world.

Meaning of the wave function

by Shan Gao

International Journal of Quantum Chemistry, 111, 4124-4138 (2011).

We investigate the meaning of the wave function by analyzing the mass and charge density distributions of a quantum... more We investigate the meaning of the wave function by analyzing the mass and charge density distributions of a quantum system. According to protective measurement, a charged quantum system has effective mass and charge density distributing in space, proportional to the square of the absolute value of its wave function. In a realistic interpretation, the wave function of a quantum system can be taken as a description of either a physical field or the ergodic motion of a particle. The essential difference between a field and the ergodic motion of a particle lies in the property of simultaneity; a field exists throughout space simultaneously, whereas the ergodic motion of a particle exists throughout space in a time-divided way. If the wave function is a physical field, then the mass and charge density will be distributed in space simultaneously for a charged quantum system, and thus, there will exist gravitational and electrostatic self-interactions of its wave function. This not only violates the superposition principle of quantum mechanics but also contradicts experimental observations. Thus, the wave function cannot be a description of a physical field but a description of the ergodic motion of a particle. For the later, there is only a localized particle with mass and charge at every instant, and thus, there will not exist any self-interaction for the wave function. It is further argued that the classical ergodic models, which assume continuous motion of particles, cannot be consistent with quantum mechanics. On the basis of negative result, we suggest that the wave function is a description of the quantum motion of particles, which is random and discontinuous in nature. On this interpretation, the square of the absolute value of the wave function not only gives the probability of the particle being found in certain locations but also gives the objective probability of the particle being there. We show that this new interpretation of the wave function provides a natural realistic alternative to the orthodox interpretation, and its implications for other realistic interpretations of quantum mechanics are also briefly discussed.

Quantum collapse, consciousness and superluminal communication

by Shan Gao

Foundations of Physics Letters 17 (2004) 167-182.

The relation between quantum collapse, consciousness and superluminal communication is analyzed. As we know, quantum... more The relation between quantum collapse, consciousness and superluminal communication is analyzed. As we know, quantum collapse, if exists, can result in the appearance of quantum nonlocality, and requires the existence of a preferred Lorentz frame. This may permit the realization of quantum superluminal communication (QSC), which will no longer result in the usual causal loop in case of the existence of a preferred Lorentz frame. The possibility of the existence of QSC is further analyzed under the assumption that quantum collapse is a real process. We demonstrate that the combination of quantum collapse and the consciousness of the observer will permit the observer to distinguish nonorthogonal states in principle. This provides a possible way to realize QSC. Some implications of the existence of QSC are briefy discussed.

Does gravity induce wavefunction collapse? An examination of Penrose's argument

by Shan Gao

Draft Version

According to Penrose, the fundamental conflict between the superposition principle of quantum mechanics and the... more According to Penrose, the fundamental conflict between the superposition principle of quantum mechanics and the general covariance principle of general relativity entails the existence of wavefunction collapse, e.g. a quantum superposition of two different space-time geometries will collapse to one of them due to the ill-definedness of the time-translation operator for the superposition. In this paper, we argue that Penrose's conjecture on gravity's role in wavefunction collapse is debatable. First of all, it is still a controversial issue what the exact nature of the conflict is and how to resolve it. Secondly, Penrose's argument by analogy is too weak to establish a necessary connection between wavefunction collapse and the conflict as understood by him. Thirdly, the conflict does not necessarily lead to wavefunction collapse. For the conflict or the problem of ill-definedness for a superposition of different space-time geometries also needs to be solved before the collapse of the superposition finishes, and once the conflict has been resolved, the wavefunction collapse will lose its physical basis relating to the conflict. In addition, we argue that Penrose's suggestions for the collapse time formula and collapse states are also problematic.

A model of wavefunction collapse in discrete space-time

by Shan Gao

International Journal of Theoretical Physics 45, 1965-1979.

We give a new argument supporting a gravitational role in quantum collapse. It is demonstrated that the discreteness... more We give a new argument supporting a gravitational role in quantum collapse. It is demonstrated that the discreteness of space-time, which results from the proper combination of quantum theory and general relativity, may inevitably result in the dynamical collapse of the wave function. Moreover, the minimum size of discrete space-time yields a plausible collapse criterion consistent with experiments. By assuming that the source to collapse the wave function is the inherent random motion of particles described by the wave function, we further propose a concrete model of wavefunction collapse in the discrete space-time. It is shown that the model is consistent with the existing experiments and macroscopic experiences.

Is Gravity an Entropic Force?

by Shan Gao

Entropy special issue “Black Hole Thermodynamics”, Jacob D. Bekenstein (eds). 13, 936-948 (2011).

The remarkable connections between gravity and thermodynamics seem to imply that gravity is not fundamental but... more The remarkable connections between gravity and thermodynamics seem to imply that gravity is not fundamental but emergent, and in particular, as Verlinde suggested, gravity is probably an entropic force. In this paper, we will argue that the idea of gravity as an entropic force is debatable. It is shown that there is no convincing analogy between gravity and entropic force in Verlinde’s example. Neither holographic screen nor test particle satisfies all requirements for the existence of entropic force in a thermodynamics system. Furthermore, we show that the entropy increase of the screen is not caused by its statistical tendency to increase entropy as required by the existence of entropic force, but in fact caused by gravity. Therefore, Verlinde’s argument for the entropic origin of gravity is problematic. In addition, we argue that the existence of a minimum size of spacetime, together with the Heisenberg uncertainty principle in quantum theory, may imply the fundamental existence of gravity as a geometric property of spacetime. This may provide a further support for the conclusion that gravity is not an entropic force.

What is a mechanism?: Thinking about mechanisms across the sciences

by Phyllis Illari

With Jon Williamson. European Journal for the Philosophy of Science, Volume 2(1) (2012) 119-135
DOI 10.1007/s13194-011-0038-2

After a decade of intense debate about mechanisms, there is still no consensus characterization. In this paper we... more After a decade of intense debate about mechanisms, there is still no consensus characterization. In this paper we argue for a characterization that applies widely to mechanisms across the sciences. We examine and defend our disagreements with the major current contenders for characterizations of mechanisms. Ultimately, we indicate that the major contenders can all sign up to our characterization.

More really is different

by Mile Gu

Sharpening Occam's Razor with Quantum Mechanics

by Mile Gu

The World in the Data

by Don Ross

Co-authored with James Ladyman

The paper compares Ladyman & Ross’s version of naturalized metaphysics, Rainforest Realism, with the comprehensive... more The paper compares Ladyman & Ross’s version of naturalized metaphysics, Rainforest Realism, with the comprehensive scientific metaphysics recently articulated by a physicist, David Deutsch. Major similarities of the two positions are described and discussed, illustrating the relevance of metaphysics to science. However, a failure of consistent naturalism on Deutsch’s part is also identified and criticized: Deutsch promotes the Everettian multiverse interpretation of quantum physics on the basis of a philosophical commitment to classical determinism. He also fails to appreciate that a broadly realistic attitude to physical theory does not require denying that some important scientific achievements involve using models and their elements as instruments. Both of these errors are traced to an overly strict dichotomy between pure formalism and empirically interpreted content. In quantum mechanics, Bohr’s version of the Copenhagen interpretation fails to be a fully fledged ‘interpretation’ according to currently dominant philosophical opinion. We criticize this opinion. The deep structure of the world is arguably not mathematical but statistical, and there is no such thing as ‘purely formal statistics’. The principles of statistics are generalizations of recurrent patterns found in data; and such structuring of data is the core business of both science and its metaphysical unification. Contrary to Deutsch’s claims, Enlightenment optimism about the capacity for limitless expansion of knowledge is compatible with the hypothesis that the world is irreducibly and fundamentally stochastic. Among great philosophers, C.S. Pearce anticipated this hypothesis. Ladyman & Ross’s metaphysics can be redescribed in terms of it, as follows: the world is the totality of non-redundant statistics, not of things.

Is the Universe Rational?

by Taner Edis

Free Inquiry, 30:2 27-29 (2010)

Matter and selfhood in Kant’s Physics: A Contemporary Reappraisal.

by Paulo Jesus

Lori, N. & Jesus, P. (2010). Matter and selfhood in Kant’s Physics: A Contemporary Reappraisal. In E. Pires, B. Nonnenmacher & S. Von Stupnagel (Eds.), Relations of the Self. Bezüge des Selbst. Selbstreferentielle Prozesse in philosophischen Perspektiven (p. 207-227) (Coimbra University, Portugal, March 12-14, 2009). Coimbra: Coimbra University Press.

The son of Werner Heisenberg and nephew-in-law of Carl Friedrich von Weizsäcker, the neurobiologist Martin Heisenberg,... more The son of Werner Heisenberg and nephew-in-law of Carl Friedrich von Weizsäcker, the neurobiologist Martin Heisenberg, who has worked extensively on the neurogenetics of Drosophila, has recently proposed that quantum physics and behavioral biology can solve the Kantian third antinomy in which Reason (Vernunft) appears to be hostage of an insurmountable conflict with itself concerning the contradictory coexistence of two types of causality, namely “causality in accordance with laws of nature” and “causality through freedom” (A444/B472 ff.)3. To be sure, the novelty of Heisenberg’s proposal does not reside in the idea that the third antinomy is solvable, since for Kant the antinomy is nothing but an illusory contradiction that can be easily “dismantled” and avoided by distinguishing appearances or phenomena (mere representations) that are embedded in an empirically conditioned series in time and space from things in themselves whose intelligible being is situated outside any sensible conditions and enjoys total inde-pendence of all empirical laws. Thus, for him, if the Antinomy is truly understood, then its antinomic structure is dissolved. Indeed, Kant admits that both the realm of empirical causality, which guarantees
the unity of experience, i.e. a necessary chain of time-determined occurrences, and the realm of intelligible causality, which constitutes the power of beginning an original action from
oneself, can coexist effectively, although in different levels of reality as it were. Both models of causality are “true at the same time but in a different relation”.

Truth and Physics Education.

by Robert Shaw

Robert Keith Shaw (2010). Truth and Physics Education. Doctoral dissertation, University of Auckland

This thesis develops a hermeneutic philosophy of science to provide insights into physics education. -/- Modernity... more This thesis develops a hermeneutic philosophy of science to provide insights into physics education. -/- Modernity cloaks the authentic character of modern physics whenever discoveries entertain us or we judge theory by its use. Those who justify physics education through an appeal to its utility, or who reject truth as an aspect of physics, relativists and constructivists, misunderstand the nature of physics. Demonstrations, not experiments, reveal the essence of physics as two characteristic engagements with truth. First, truth in its guise as correspondence enables a human being to prepare for the distinctive event of physics. Second, the event of physics occurs in human perception when someone forces a hidden reality to disclose an aspect of itself. Thus, the ground of physics is our human involvement with reality achieved by way of truth. To support this account of physics, the thesis reports phenomenological investigations into Isaac Newton’s involvement with optics and a secondary school physics laboratory. These involve interpretations of Heidegger’s theory of beings, schema and signification. The project draws upon, and contributes to, the hermeneutic phenomenology of modern physics, a tradition in continental philosophy that begins with Immanuel Kant, and advances particularly from Martin Heidegger to Patrick Heelan. The thesis advocates an ontological pedagogy for modern physics which has as its purpose each individual student’s engagement with reality and truth. Students may achieve this through demonstrations of phenomena that will enable them to dwell with physics, an experience that contrasts with their embroilment in modernity, and which perpetuates nature’s own science.

Stories about the noncommutative world. Story 2. Definitions (2011)

by François-Igor Pris

Some basic definitions of noncommutative spaces are provided. Some basic definitions of noncommutative spaces are provided.