This chapter examines the nature of physical reality in the context of unavoidable unobservables in physics. One of the features of science, especially physical science, is a powerful urge to construct theories of phenomena, instead of just cataloging and classifying phenomena and their spatio-temporal patterns. The concept of fields' of various kinds dominates physical theory and modern physics, and fields are essential to both classical and quantum theories. The concept of physical reality in the context of the Einstein, Podolsky and Rosen (EPR) assertion of the incompleteness of quantum mechanics is perhaps appropriate. Quantum theory of physical systems consisting of large number of particles led to the concept of a quantum field associated with the particles, a generalisation of the wave function itself. Space and time are supreme and primary unobservables in physics, without any reality independent of matter, notwithstanding their modern status as the dynamical arena of gravitational effects as described in Einstein's general theory of relativity.
This chapter examines the nature of physical reality in the context of unavoidable unobservables in physics. One of the features of science, especially physical science, is a powerful urge to construct theories of phenomena, instead of just cataloging and classifying phenomena and their spatio-temporal patterns. The concept of fields' of various kinds dominates physical theory and modern physics, and fields are essential to both classical and quantum theories. The concept of physical reality in the context of the Einstein, Podolsky and Rosen (EPR) assertion of the incompleteness of quantum mechanics is perhaps appropriate. Quantum theory of physical systems consisting of large number of particles led to the concept of a quantum field associated with the particles, a generalisation of the wave function itself. Space and time are supreme and primary unobservables in physics, without any reality independent of matter, notwithstanding their modern status as the dynamical arena of gravitational effects as described in Einstein's general theory of relativity.
The fundamental physical theories that interpret and explain behaviour of matter in nature are dependent on several unobservables and insensibles in their construction. While a rigorous natural philosophy cannot take them for granted, there does not seem to be a way of avoiding such unobservables in our theories. While a program to banish all unobservables from physical theory is unlikely to succeed, and perhaps even unnecessary, they are both the strong and weak points of the theoretical descriptions of physical nature. Analyzing them for empirical and philosophical consistency and integrity is always a promising path towards a better theory. In this paper, I examine the nature of physical reality in the context of unobservables in physics and discuss three examples. One is about the apparent loss of physical reality due to the need for a consistent quantum mechanical representation. The second example deals with the conflict between the assumed reality of quantum fields, so fundamental and essential to our standard physics worldview, and the dynamics of the observable universe. The third deals with an all-important difference between conventional modern physics constructed in the unreal and unobservable empty `space' and an empirically and logically determined physics with matter-filled universe as its arena. The acknowledgment of the observable matter-filled universe necessitates reformulation of dynamics with total relativity. Not surprisingly, this paradigm with its universal cosmic links also holds human concepts of harmony and beauty.
From a phenomenological and experimental viewpoint, quantum mechanics is remarkably successful in explaining effects and processes in the microscopic world. Recently, however, a growing body of literature has revisited the theory's own formal foundations, specifically addressing issues of self-consistency and completeness. As a major historical example of these foundational challenges, the Einstein-Podolsky-Rosen (EPR) argument famously claimed that the theory is incomplete. While many valid criticisms and refutations of the EPR logic exist, they generally rely on a combination of technical results and conceptual objections to EPR's interpretive assumptions, thus transcending the plain quantum framework itself. Motivated by these trends of examining the theory's structural limits, here we revisit the EPR argument. Focusing on elements essential to the EPR reasoning, we first analyze general quantum correlations for EPR states: (i) the fact that their observables are always associated with non-commuting operators, and (ii) the nature of the correlated information obtained through measurement. From these two points alone, and relying strictly on the core rules of quantum mechanics, we demonstrate how to overturn the alleged EPR incompleteness without invoking any extraneous propositions. Consequently, we show that the standard formalism alone suffices to resolve such type of skepticism regarding the theory's physical reach. This offers, at least in a paradigmatic instance, a powerful indication of a structurally well-founded, self-consistent quantum theory.
The fundamental physical theories that interpret and explain behaviour of matter in nature are dependent on several unobservables and insensibles in their construction.While a rigorous natural philosophy cannot take them for granted, there does not seem to be a way of avoiding such unobservables in our theories.While a program to banish all unobservables from physical theory is unlikely to succeed, and perhaps even unnecessary, they are both the strong and weak points of the theoretical descriptions of physical nature.Analyzing them for empirical and philosophical consistency and integrity is always a promising path towards a better theory.In this paper, I examine the nature of physical reality in the context of unobservables in physics and discuss three examples.One is about the apparent loss of physical reality due to the need for a consistent quantum mechanical representation.The second example deals with the conflict between the assumed reality of quantum fields, so fundamental and essential to our standard physics worldview, and the dynamics of the observable universe.The third deals with an allimportant difference between conventional modern physics constructed in the unreal and unobservable empty 'space' and an empirically and logically determined physics with matter-filled universe as its arena.The acknowledgment of the observable matter-filled universe necessitates reformulation of dynamics with total relativity.Not surprisingly, this paradigm with its universal cosmic links also holds human concepts of harmony and beauty.
Causal set theory starts out from a central result in general relativity according to which the causal structure determines, up to a so-called ‘conformal factor’, the geometry of a relativistic spacetime. Space and time, it seems, must be part and parcel of the ontology of any physical theory, of any theory with a credible claim to being a physical theory, that is. After all, physics is the science of the fundamental constitution of the material bodies, their motion in space and time, and indeed of space and time themselves. There are two areas in physics in which space or spacetime may emerge from something qualitatively rather different: wave function monism in quantum mechanics and quantum theories of gravity. The former case concerns a particular interpretative issue in non-relativistic quantum mechanics. The severity and the characteristics of the disappearance of spacetime differ from one approach to quantum gravity to another.
Taking into account the results that we have been obtained during the last decade in the foundations of quantum mechanic we put forward a view on reality that we call the 'creation discovery view'. In this view it is made explicit that a measurement is an act of a macroscopic physical entity on a microphysical entity that entails the creation of new elements of reality as well as the detection of existing elements of reality. Within this view most of the quantum mechanical paradoxes are due to structural shortcomings of the standard quantum theory, which means that our analysis agrees with the claim made in the Einstein Podolsky Rosen paper, namely that standards quantum mechanics is an incomplete theory. This incompleteness is however not due to the absence of hidden variables but to the impossibility for standard quantum mechanics to describe separated quantum entities. Nonlocality appears as a genuine property of nature in our view and makes it necessary to reconsider the role of space in reality. Our proposal for a new interpretation for space makes it possible to put forward an new hypothesis for why it has not been possible to unify quantum mechanics and relativity theory.
Quantum mechanics is considered to be one of the most successful as well as revolutionary theories in the history of physics. It gives the conceptual and mathematical basis of the behavior of matter and energy at atomic and subatomic level. In the course of time quantum mechanics has grown out of a theory that was created to cover experimental anomalies to a comprehensive theory that forms the basis of theoretical physics as known today. Its use is much broader to the early atomic models and now it is central to quantum field theory, particle physics and condensed matter physics, cosmology, and new theories of quantum gravity. Quantum mechanics has a significant impact on the philosophical concept of physical reality because of its abstract nature, the probabilistic nature of its interpretations, wave functions and non-local correlations. The classical physics, in contrast to quantum mechanics, presupposes the determinism and exact predictability of the phenomena; quantum mechanics regards the unpredictability of phenomena as the natural law. This change of thought has enabled physicists to develop a set of theoretical frameworks, which better capture experimental data, especially at gross extremes of energy and space. Quantum mechanics is a theory and a method of modern theoretical physics. It allows the development of field theories of the description of fundamental interactions, predicts the occurrence of previously unknown particles, and the explanation of complex collective phenomena in many-body systems. Moreover, additional quantum concepts have already become essential in the study of the early universe, black holes and microphysical geometry of space-time. The purpose of the research paper is to examine the vast number of theoretical physics studies using quantum mechanics as a tool. The paper has emphasised the contribution of quantum mechanics in the current research on the study of unification of physical theories as it is manifested in key subfields to which quantum mechanics has made contributions. There are also some reflections of where quantum mechanics is likely to make a paradigm shift in the future that confirm its relevance as a fundamental pillar of theoretical physics.