# "B" is for Bohr

## TL;DR

This paper argues that Bohr's philosophical insights are central to QBism, emphasizing the importance of human experience and contextuality in understanding quantum phenomena, and clarifies how QBism extends Bohr's ideas.

## Contribution

It offers a philosophical analysis linking Bohr's ideas to QBism, highlighting the role of human experience and contextuality in quantum physics.

## Key findings

- Bohr's concept of contextuality is fundamental to understanding quantum phenomena.
- QBism emphasizes the subjective experience, extending Bohr's ideas.
- Bohr's insights help clarify and strengthen the philosophical foundations of QBism.

## Abstract

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.