Redefining the Observer Effect: Toward a Broad Observer Effect as Constraint Rather Than Action

Abstract

This concept paper proposes a broader definition of the observer effect: not only the disturbance caused by observation, but also the way visibility, invisibility, and apparent naturalness are shaped by the observer’s structure, position, ability, environment, connecting apparatus, and descriptive system. It distinguishes active observer effects, where observation alters the object, from passive observer effects, where being an observer constrains what can be seen, resolved, reconstructed, and theoretically closed. Passive observer effects are further divided into internal effects, arising from the observer’s own structure and performance, and external effects, arising from the observer’s environment and position. Based on this framework, the paper offers a unified way to organize human observers, instruments, theoretical descriptions, approximations, assumptions, and even the axiomatization of vague concepts. Unreviewed conceptual preprint. PDFs in English and Japanese. Generative AI tools were used for language refinement and translation support; the author takes full responsibility for the final text, references, and claims. Keywordsobserver effect, internal observer, passive observer effect, relative a priori order, observational instrument, composite observer, effective state space, approximation, ideal system, axiomatic physics