Niels Bohr as Philosopher of Experiment: Does Decoherence Theory Challenge Bohr's Doctrine of Classical Concepts?

TL;DR

This paper reinterprets Bohr's doctrine of classical concepts as an epistemological stance rooted in experimental function, arguing it does not conflict with decoherence theory's dynamical approach to quantum-classical transition.

Contribution

It offers a new historical analysis clarifying Bohr's epistemological view and its distinction from dynamical explanations, challenging common misunderstandings in the literature.

Findings

Bohr's doctrine is epistemological, not ontological.

Disagreement between Bohr and Heisenberg about the 'cut' supports this view.

Bohr's doctrine is compatible with decoherence-based solutions.

Abstract

Niels Bohr's doctrine of the primacy of "classical concepts" is arguably his most criticized and misunderstood view. We present a new, careful historical analysis that makes clear that Bohr's doctrine was primarily an epistemological thesis, derived from his understanding of the functional role of experiment. A hitherto largely overlooked disagreement between Bohr and Heisenberg about the movability of the "cut" between measuring apparatus and observed quantum system supports the view that, for Bohr, such a cut did not originate in dynamical (ontological) considerations, but rather in functional (epistemological) considerations. As such, both the motivation and the target of Bohr's doctrine of classical concepts are of a fundamentally different nature than what is understood as the dynamical problem of the quantum-to-classical transition. Our analysis suggests that, contrary to claims often found in the literature, Bohr's doctrine is not, and cannot be, at odds with proposed solutions to the dynamical problem of the quantum-classical transition that were pursued by several of Bohr's followers and culminated in the development of decoherence theory.