## 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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## References

- Aerts D. (1994) Quantum structures, separated physical entities and probability. Foundations of Physics 24: 1227CrossRefGoogle Scholar
- Aerts D. (1996a) Relativity theory: What is reality?. Foundations of Physics 6: 1627–1644CrossRefGoogle Scholar
- Aerts D. (1996b) Towards a framework for possible unification of quantum and relativity theories. International Journal of Theoretical Physics 35: 2399–2416CrossRefGoogle Scholar
- Aerts D., Coecke B., D’Hooghe B., Valckenborgh F. (1997) A mechanistic macroscopic physical entity with a three-dimensional Hilbert space description. Helvetica Physica Acta 70: 793–802Google Scholar
- Aerts D. (1982) Description of many physical entities without the paradoxes encountered in quantum mechanics. Foundations of Physics 12: 1131–1170CrossRefGoogle Scholar
- Aerts D. (1984) The missing element of reality in the description of quantum mechanics of the EPR paradox situation. Helvetica Physica Acta 57: 421–428Google Scholar
- Aerts, D. (1990). An attempt to imagine parts of the reality of the micro-world. In J. Mizerski, et al. (Eds.),
*Problems in quantum physics II; Gdansk ’89*. Singapore: World Scientific Publishing Company. An Italian translation of this article is also available: “Un tentativo di immaginare parti del micromondo,” AutoRicerca (Vol. 2, pp. 77–109) (2011).Google Scholar - Aerts D. (1992a) The construction of reality and its influence on the understanding of quantum structures. International Journal of Theoretical Physics 31: 1815–1837CrossRefGoogle Scholar
- Aerts D. (1992b) A possible explanation for the probabilities of quantum mechanics. Journal of Mathematical Physics 27: 202–210CrossRefGoogle Scholar
- Aerts D. (1998) The entity and modern physics: The creation-discovery view of reality. In: Castellani E. (Ed.), Interpreting bodies: Classical and quantum objects in modern physics. Princeton Unversity Press, PrincetonGoogle Scholar
- Aerts, D. (1999a). The stuff the world is made of: Physics and reality. In D. Aerts, J. Broekaert, & E. Mathijs (Eds.),
*The white book of ‘Einstein meets Magritte*(pp. 129–183). Dordrecht: Kluwer Academic Publishers.Google Scholar - Aerts, D. (1999b). Quantum mechanics: Structures, axioms and paradoxes. In D. Aerts, J. Broekaert, & E. Mathijs (Eds.),
*The indigo book of ‘Einstein meets Magritte*(pp. 141–205). Dordrecht: Kluwer Academic Publishers.Google Scholar - Aerts, D. (2002a). Reality and probability: Introducing a new type of probability calculus. In
*Probing the structure of quantum mechanics: Nonlinearity, nonlocality, computation and axiomatics*(pp. 205–229). Singapore: World Scientific.Google Scholar - Aerts, D. (2002b). Being and change: Foundations of a realistic operational formalism. In
*Probing the Structure of quantum mechanics: Nonlinearity, nonlocality, computation and axiomatics*(pp. 71–110). Singapore: World Scientific.Google Scholar - Christiaens, W. (2002). Some notes on Aerts’ interpretation of the EPR-paradox and the violation of Bell-inequalities. In
*Probing the structure of quantum mechanics: Nonlinearity, nonlocality, computation and axiomatics*(pp. 259–286). Singapore: World Scientific.Google Scholar - Coecke B. (1995a) Hidden measurement representation for quantum entities described by finite dimensional complex Hilbert spaces. Foundations of Physics 25: 203CrossRefGoogle Scholar
- Coecke B. (1995b) Generalization of the proof on the existence of hidden measurements to experiments with an infinite set of outcomes. Foundations of Physics Letters 8: 437CrossRefGoogle Scholar
- Coecke B. (1996) New examples of hidden measurement systems and outline of a general scheme. Tatra Mountains Mathematical Publications 10: 203Google Scholar
- Conway J. H., Kochen S. (2006) The free will theorem. Foundation of Physics 36: 1441–1473CrossRefGoogle Scholar
- Conway J. H., Kochen S. (2009) The strong free will theorem. Notices of the American Mathematical Society 56: 226–232Google Scholar
- Einstein A., Podolsky B., Rosen N. (1935) Can quantum-mechanical description of physical reality be considered complete?. Physical Review 47: 777–780CrossRefGoogle Scholar
- Freeman A. et al (2005) Sheldrake and his critics: the sense of being glared at. Journal of Consciousness Studies 12(6): 1–126Google Scholar
- Gleason A. M. (1957) Measures on the closed subspaces of a Hilbert space. Journal of Mathematics and Mechanics 6: 885–893Google Scholar
- Heisenberg W. (1930) The physical principles of quantum theory. University of Chicago Press, ChicagoGoogle Scholar
- Kochen S., Specker E. P. (1967) The problem of hidden variables in quantum mechanics. Journal of Mathematics and Mechanics 17: 59–87Google Scholar
- Piron C. (1976) Foundations of quantum physics. W. A. Benjamin Inc., MassachusettsGoogle Scholar
- Piron C. (1978) La Description d’un Système Physique et le Présupposé de la Théorie Classique. Annales de la Fondation Louis de Broglie 3: 131–152Google Scholar
- Piron, C. (1990).
*Mécanique quantique. Bases et applications*. Presses polytechniques et universitaires romandes, Lausanne (Second corrected edition 1998) (1st ed.).Google Scholar - Poincaré H. (1902) La science et l’hypothèse. Flammarion, ParisGoogle Scholar
- Sassoli de Bianchi, M. (2011a). Ephemeral properties and the illusion of microscopic particles.
*Foundations of Science*, 16(4), 393–409. doi: 10.1007/s10699-011-9227-x. An Italian translation of the article is also available: “Proprietá effimere e l’illusione delle particelle microscopiche,” AutoRicerca (Vol. 2, pp. 39–76). - Sassoli de Bianchi, M. (2011b). The
*δ*-quantum machine, the*k*-model, and the non-ordinary spatiality of quantum entities. To appear in:*Foundations of Science*, arXiv:1104.4738v2 [quant-ph].Google Scholar - Sassoli de Bianchi, M. (2011c). From permanence to total availability: A quantum conceptual upgrade. To appear in:
*Foundations of Science*. doi: 10.1007/s10699-011-9233-z. - Smets S. (2005) The modes of physical properties in the logical foundations of physics. Logic and Logical Philosophy 14: 37–53Google Scholar