The distinction of external (exo) and internal (endo) perspectives is addressed with respect to the issues of observation and measurement in quantum theory. It is demonstrated how the exo/endo-terminology can be fruitfully applied to two equally important concepts of reality in the quantum world: local (common sense) reality and holistic (nonlocal) reality. Basic elements of the exo/endo-distinction are then used to interpret certain features concerning the issues of time, histories, and presence.
The distinction of external (exo) and internal (endo) perspectives is addressed with respect to the issues of observation and measurement in quantum theory. It is demonstrated how the exo/endo-terminology can be fruitfully applied to two equally important concepts of reality in the quantum world: local (common sense) reality and holistic (nonlocal) reality. Basic elements of the exo/endo-distinction are then used to interpret certain features concerning the issues of time, histories, and presence.
We argue about the following concepts:(i)introduction of endo and exo-observer of a physical system (ii) possible relation between endo, exo-observer and continuum/discrete nature of the same system (iii)the distinction about two categories of observers do not help to solve the basic nature (continuum/discrete) of the system considered. We argue that discrete math tool utilized to describe behavior of a physical system is to ascribe to the exo-observer description. In other words, discreteness nature of a system is due at the presence of an external observer description, the observation act. Vice versa, we retain, that endo-observer description give us a continuum nature of the system but only in a Platonic realm. Finally, we retain that a real theory of the state of matter could to build a real independence from the observer. These brief considerations open a discussion on the foundations of discrete math tools and their relation with the observation act, included the possible extension to foundations of the quantum mechanics.
We argue about the following concepts:(i)introduction of endo and exo-observer of a physical system (ii) possible relation between endo, exo-observer and continuum/discrete nature of the same system (iii)the distinction about two categories of observers do not help to solve the basic nature(continuum/discrete)of the system considered. We argue that discrete math tool utilized to describe behavior of a physical system is to ascribe to the exo-observer description. In other words, discreteness nature of a system is due at the presence of an external observer description, the observation act. Vice versa, we retain, that endo-observer description give us a continuum nature of the system but only in a Platonic realm. Finally, we retain that a real theory of the state of matter could to build a real independence from the observer. These brief considerations open a discussion on the foundations of discrete math tools and their relation with the observation act, included the possible extension to foundations of the quantum mechanics.
This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book reviews classical physical and quantum theories for nonspecialists, building on the basics to introduce recent advances. A definition of physical is included for specialists also to consider. The book analyzes quantum theory interpretations, revealing a developmental progression from the standard, many-worlds, decoherence/consistent histories, quantum probability, quantum information field, and transactional interpretations to neorealism. It outlines a new holistic interpretation of quantum theory; of major significance is the subtle concept of levels of spacetime. The book considers loop quantum gravity, string, inflationary big bang, and unified field theories. The diverse interpretations are in large part due to focusing on the observed as the only reality: the process of observing and the observer were practically ignored.
Abstract Apparent paradoxes in Quantum Physics demand a sharp distinction between a "real part of the world" and the realm of possibilities. In the former we may distinguish individual elements (coarse events) relating to space-time, with causal connections between them respecting the relativistic locality principle. The latter, quantitatively described by probability assignments conditioned on existing facts and depending on the definition of equivalence classes of situations, cannot be subdivided in space-time categories. There are global correlations (Pauli principle...). The cut between the realms of facts and possibilities implies an evolutionary picture of the "real world" in which the (generalized) arrow of time assumes basic significance. Some deficiencies of existing theory are pointed out.
This article surveys a selection of key conceptual and interpretational developments in quantum mechanics, tracing the theory from its foundational postulates to contemporary discussions of measurement, nonlocality, and the emergence of classicality. Beginning with the structure of Hilbert space and the postulates governing state evolution and measurement, the epistemic stance of the Copenhagen interpretation and its modern reformulations are examined. The Einstein-Podolsky-Rosen argument, Bell's theorem, and Hardy's paradox are then discussed as probes of locality and realism, alongside the deterministic but explicitly nonlocal de Broglie-Bohm theory. The measurement problem and the implications of contextuality are analyzed in relation to objective collapse models, which introduce new physical dynamics to account for definite outcomes. Finally, the role of decoherence in the suppression of interference and the emergence of classical behavior is explored, together with the interpretational frameworks of many-worlds and consistent histories. This material aims to provide a coherent introductory overview of how several of the most prominent interpretations address the central concern of what quantum mechanics tells us about the nature of physical reality.
In both quantum mechanics and relativity theory, the concept of the observer plays a critical role. However, there is no consensus on the definition of observer in these theories. Following Einstein's thought experiments, one could ask: What would it look like to sit inside a photon or to be a photon? And what type of observer could represent this more global perspective of the photon's interior? To address these questions, we introduce the concepts of internal and external observers with a focus on their relationship in quantum theory and relativity theory. The internal observer, associated with the internal observables super-algebra, glues the external interactions. Drawing inspiration from the advancements in abstract algebraic topology, we propose mathematical representation of the internal observer. We also outline principles for ensuring the consistency of observers in terms of information theory. It becomes evident, through the analysis of the introduced hierarchy of observers, that entanglement is a primitive of space-time causal relationships. While external observers must abide by the relativistic causality linked with the no-signaling principle in quantum mechanics, the internal observer is inherently non-local and may be acausal. However, its consistency is maintained through the formulation of the self-consistency principle. One of the goals of this paper is to construct the representation of the internal observer from the local external algebra of observables, which can be associated with external observers. Additionally, we demonstrate how the concepts of internal and external observers can be applied in the fields of quantum information theory, algebraic quantum field theory, and loop quantum gravity. The concept of internal observer seems to be also fundamental for further development of quantum gravity.