Friendly thoughts on thoughtful friendliness

TL;DR

The paper critiques the assumptions and motivations behind the local friendliness no-go theorem and its experimental tests, questioning their validity within quantum theory and proposing conceptual clarifications.

Contribution

It analyzes the assumptions of the local friendliness theorem, highlighting the need for stronger conditions and clarifying the concept of 'thoughtfulness' in the context of quantum experiments.

Findings

Assumptions need strengthening to exclude variable agent numbers.

Natural emergence of variable agents in quantum theory scenarios.

Motivations for assumptions may be insufficient under current definitions.

Abstract

We discuss Wiseman, Cavalcanti and Rieffel's "thoughtful" local friendliness no-go theorem and the experimental programme they propose to test local friendliness inequalities. We argue that, to prove the theorem, the assumptions need to be strengthened to exclude the possibility of variable numbers of thoughtful agents existing in different phases of the experiment. We argue further that this possibility may arise naturally, even in one-world versions of quantum theory. We also query whether the motivations they give for their assumptions hold up well under their definition of "thoughtfulness" as displaying human-level cognitive ability, and suggest that their justification requires replacing "thoughtfulness" by "consciousness" or "conscious thoughtfulness".