A recent paper by Frauchiger and Renner has brought to light a serious problem with  conventional approaches to quantum theory, by deriving a contradiction using those approaches. In  FR Paradox Kastner 10.17.19  I argue that the paradox shows that quantum theory leads to absurdities and inconsistencies unless there is a clear physical criterion for 'measurement'.  … Continue reading Latest incarnation of the Schrödinger Cat Paradox forces a new view of quantum theory →

The so-called 'quantum eraser' is an experiment that has prompted widespread confusion. In fact, it is nothing more than a photonic version of the EPR experiment. Nothing is erased, and there is no necessary retrocausation or 'temporal nonlocality,' beyond standard EPR correlations. I attempt to clear up the confusion in this paper, which has now … Continue reading The ‘Delayed Choice Quantum Eraser’ Neither Erases Nor Delays →

Bernice Kastner is a math educator whose innovative approach has helped to transform classrooms and enable many students to gain confidence and mastery in math. (She also happens to be my mother.) Her new book, The Role of Language in Teaching Children Math, is now out: https://www.austinmacauley.com/us/book/role-language-teaching-children-math From the publisher: "It can be difficult to … Continue reading Important New Book on Math Education →

In this publication, I address popular uses of the term 'retrocausation' in connection with quantum theory, and find that there is much that needs to be corrected and clarified. Much of the discussion in the literature on this topic involves inconsistencies and equivocation about what retrocausation really is, and about what it can do.  In … Continue reading A critical look at popular ‘retrocausation’ claims. Do they hold up? →

https://alonzipodcast.com/wp/2018/11/01/our-unseen-reality-the-relativistic-transactional-interpretation-of-quantum-mechanics-with-ruth-kastner/ Note correction: I should have said that a real photon goes FROM the emitter TO the absorber (said it backwards, LOL).

I had fun in Buenos Aires last summer with the great people in the Grupo de Filosofía de las Ciencias. Here is my talk on how to understand the emergence of classicality from the quantum level in the context of statistical approaches. https://youtu.be/kvXYmB2qj88

This post is a critique of an interpretational approach to quantum theory known as "Qbism."  Qbism is currently advocated primarily by Fuchs, Mermin, and Schack.  Here, I discuss a little-known but powerful and important argument from Joe Henson regarding Qbism. Henson's argument discloses a crucial fallacy in Qbism's claim to "save locality" in quantum theory; … Continue reading Why “making sense of quantum theory” by denying that theories are about the world does not really work →

via A quantum myth for our times

A talk given at the University of Buenos Aires in June 2017 on the difference between classical systems and quantum ones: https://www.youtube.com/watch?v=kvXYmB2qj88&feature=youtu.be   (Note: Some of the slides were missing text here and there due to a compatibility issue; the correct version is provided here: Baires 2017 slides)

This is a preprint version of this paper: AIP Conference Proceedings 1841, 020002 (2017) R. E. Kastner Abstract. Time-symmetric interpretations of quantum theory are often presented as featuring "retrocausal" effects in addition to the usual forward notion of causation. This paper examines the ontological implications of certain time- symmetric theories, and finds that no dynamical notion … Continue reading Is There Really “Retrocausation” in Time-Symmetric Approaches to Quantum Mechanics? →