My Struggles with the Block Universe

TL;DR

This paper discusses the development of Quantum Bayesianism (QBism) as a new interpretation of quantum mechanics, highlighting its historical context, philosophical implications, and its divergence from traditional Copenhagen views.

Contribution

It offers a detailed historical and philosophical account of QBism's emergence and aims to position it as a viable interpretation within quantum foundations.

Findings

QBism evolved from quantum Bayesian ideas.

Historical anecdotes on quantum information terminology.

Philosophical arguments supporting QBism's viability.

Abstract

This document is the second installment of three in the Cerro Grande Fire Series. Like its predecessor arXiv:quant-ph/0105039, "Notes on a Paulian Idea," it is a collection of letters written to various friends and colleagues, most of whom regularly circuit this archive. The unifying theme of all the letters is that each has something to do with the quantum. Particularly, the collection chronicles the emergence of Quantum Bayesianism as a robust view of quantum theory, eventually evolving into the still-more-radical "QBism" (with the B standing for no particular designation anymore), as it took its most distinctive turn away from various Copenhagen Interpretations. Included are many anecdotes from the history of quantum information theory: for instance, the story of the origin of the terms "qubit" and "quantum information" from their originator's own mouth, a copy of a rejection letter written by E. T. Jaynes for one of Rolf Landauer's original erasure-cost principle papers, and much more. Specialized indices are devoted to historical, technical, and philosophical matters. More roundly, the document is an attempt to provide an essential ingredient, unavailable anywhere else, for turning QBism into a live option within the vast spectrum of quantum foundational thought.