## Abstract

Founding our analysis on the *Geneva-Brussels* approach to the foundations of physics, we provide a clarification and classification of the key concept of observation. An entity can be observed with or without a scope. In the second case, the observation is a purely non-invasive discovery process; in the first case, it is a purely invasive process, which can involve either creation or destruction aspects. An entity can also be observed with or without a full control over the observational process. In the latter case, the observation can be described by a *symmetry breaking* mechanism, through which a specific deterministic observational process is selected among a number of potential ones, as explained in Aerts’ *hidden measurement approach*. This is what is called a product test, or *product observation*, whose consequences are that outcomes can only be predicted in probabilistic terms, as it is the case in typical quantum measurements. We also show that observations can be about *intrinsic* (stable) properties of the observed entity, or about *relational* (ephemeral) properties between the observer and observed entities; also, they can be about intermediate properties, neither purely classical, nor purely quantum. Our analysis allows us to propose a general conceptual characterization of quantum measurements, as observational processes involving three aspects: (1) product observations, (2) pure creation aspects and (3) ephemeral relational properties. We also discuss the important concept of *non-spatiality* and emphasize some of the differences and similarities between quantum and classical/relativistic observations.

### Keywords

Observation Quantum measurement Creation Discovery Intrinsic properties Relational properties## Preview

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