There has recently been renewed discussion of an experiment involving nested interferometers (presented by Danan et al, 2013). This experiment has been used by those authors (and others) to argue for the correctnesss of a formulation of quantum theory known as the "Two State Vector Formalism: (TSVF). In this paper, I take a close look … Continue reading Where Photons Have Been: nowhere without all of their wavefunctions →

This is a paper that I presented at a 2024 conference in honor of author Iain McGilchrist at the Center for Process Studies in San Francisco. It argues that the Western intellectual tradition, despite its many accomplishments, is critically deficient not only in modes of thought naturally associated with the brain's right hemisphere but also … Continue reading The Quantum Master and its Classical Emissary →

In this post, I offer a (hopefully) user-friendly conceptual introduction to gravitation as an entropic force, from the perspective of the transactional formulation. This account departs somewhat from traditional presentations of entropic gravity and the holographic principle by insisting that "information" alone is not physically sufficient to define thermodynamic entropy. Entropy must always be defined … Continue reading Entropic Force and Gravitation →

I previously posted a draft version of a paper pointing out that "Relational Quantum Mechanics" (RQM), an interpretation proposed by C. Rovelli, is faced with serious, arguably fatal problems. That paper has gone through the review process for the journal Philosophy of Physics and is now provisionally accepted (pending minor revisions). Here is the final … Continue reading Forthcoming in Philosophy of Physics: “Relational Quantum Mechanics” is fatally flawed. →

The authors have attempted to save "Relational Quantum Theory" from the well-known inconsistency problems of conventional quantum theory. I argue that they fail rather spectacularly. Comments welcome: https://philsci-archive.pitt.edu/23634/

Ruth E. Kastner University of Maryland, College Park October 7, 2023 ABSTRACT. This essay offers a meta-level analysis in the sociology and history of physics in the context of the "Arrow of Time" or so-called "Two Times" problem. In effect, it argues that the two topics are intertwined, and it is only by coming to … Continue reading The Arrow of Time is Alive and Well but Forbidden Under the Received View of Physics →

Yes, Hugh Everett had a novel idea. And yes, it makes for a great science fiction story. But does it really do what it claims to do? In this paper, excerpted from an edited volume with colleagues Jasmina Jeknic-Dugic and George Jaroskiewicz, I provide some reasons for concern. The Illusory Appeal of Decoherence in the … Continue reading It’s time to consider the serious flaws in the Everettian (“Many Worlds”) Interpretation →

Landauer's Principle is the claim that any computational process that "merges two computational paths" comes with an entropy cost of (at least) k ln 2. This sort of merging is also termed "erasure of information" in the literature. Thus, Landauer's Principle asserts that there is a minimal cost paid in the creation of thermodynamic entropy … Continue reading Landauer’s Principle: Not quite what Landauer had in mind. →

This is an invited contribution to a special issue of InterdisciplinaryScience Reviews honoring Sir Roger Penrose. In it, I argue that standard quantum theory faces serious anomalies that can only be rectified by including real, physical reduction currently lacking in its traditionally accepted/entrenched formulation. qm-needs-real-reduction_penrose-volDownload

In this publication, I propose a way to understand the "exchange" of indices in collective states of two or more identical quanta, and I also question certain assumptions of the standard debate on this topic. Questions/comments welcome. I can also be contacted through my author site: ruthekastner.org quantum-haecceity-kastner-pta-3.19.23_accepted_versionDownload