This article presents a correspondence dictionary — a practical tool for transitioning from the tangled “informational language” to clear physical language in fundamental physics. The dictionary is based on the distinction of three senses of the word “information” introduced in Article 1 of the series: (1) configuration of a physical system (ontological), (2) observer’s knowledge (epistemic), (3) information as an independent entity (a metaphysical construct to be rejected). The dictionary covers key concepts reformulated in the previous articles of the series: the “collapsar information paradox”, Landauer’s principle, the holographic principle, Wheeler’s “Everything is information” thesis, entropy as “missing information”, and collapsar entropy. For each concept, tables are provided that replace informational formulations with physical ones. The extended dictionary includes additional terms: amount of information, quantum information, transmission, storage, processing and erasure of information, bit, and qubit. In the transitional period, it is recommended to use constructions with explanatory parentheses, for example: “configuration (information in the sense of the physical state of a system)”. The dictionary is addressed to authors of scientific articles, lecturers, students, and journal editors. Its goal is not to abolish the use of the word “information” in communication theory or quantum computing, but to offer a clear alternative where confusion of meanings creates pseudo‑problems. Keywords: dictionary, informational language, physical language, configuration, observer’s knowledge, reformulation.
This article presents a correspondence dictionary — a practical tool for transitioning from the tangled “informational language” to clear physical language in fundamental physics. The dictionary is based on the distinction of three senses of the word “information” introduced in Article 1 of the series: (1) configuration of a physical system (ontological), (2) observer’s knowledge (epistemic), (3) information as an independent entity (a metaphysical construct to be rejected). The dictionary covers key concepts reformulated in the previous articles of the series: the “collapsar information paradox”, Landauer’s principle, the holographic principle, Wheeler’s “Everything is information” thesis, entropy as “missing information”, and collapsar entropy. For each concept, tables are provided that replace informational formulations with physical ones. The extended dictionary includes additional terms: amount of information, quantum information, transmission, storage, processing and erasure of information, bit, and qubit. In the transitional period, it is recommended to use constructions with explanatory parentheses, for example: “configuration (information in the sense of the physical state of a system)”. The dictionary is addressed to authors of scientific articles, lecturers, students, and journal editors. Its goal is not to abolish the use of the word “information” in communication theory or quantum computing, but to offer a clear alternative where confusion of meanings creates pseudo‑problems. Keywords: dictionary, informational language, physical language, configuration, observer’s knowledge, reformulation.
This programmatic article (zeroth in the series “Reformulating Key Concepts of Physics Without Informational Language”) outlines a systematic replacement of “informational language” by physical language. It shows that many paradoxes of modern physics — the collapsar information paradox, Landauer’s principle as “proof of the physicality of information”, the holographic principle as “the informational nature of reality”, and Wheeler’s thesis “It from Bit” (“Everything from the bit”) — arise from conflating three senses of the word “information”: configuration (physical state), observer’s knowledge (epistemic category), and pseudosubstance (metaphysical construct, to be rejected). The key distinction between the ontic (pertaining to reality itself) and the epistemic (pertaining to our knowledge) is introduced. Confusing these levels is the root of pseudo‑paradoxes. On this basis, the article proposes to reformulate eight key concepts (each covered in a separate article of the series): the collapsar pseudo‑paradox, Landauer’s principle, the holographic principle, Wheeler’s thesis, entropy as “missing information”, as well as to compile a correspondence dictionary, analyse the firewall paradox, and address the technical problem of quantum state recovery. The aim of the reformulation is to eliminate pseudo‑problems, return physics to describing matter, fields, and space‑time, and provide a practical tool (dictionary) for switching to clear physical language. The article invites the scientific community to discussion. Keywords: informational language, reformulation, ontic, epistemic, collapsar, programmatic article.
In contemporary physical discourse, the term “information” is used in at least three different senses, which are often conflated, creating pseudo‑problems — the most striking example being the “black hole information paradox”. This article identifies these three phenomena and proposes separate, correct terms for each. The first phenomenon is information as the configuration of a physical system (the microscopic state of fields and particles). This is an ontic phenomenon, existing independently of any observer. The author proposes calling it “configuration” (information in the sense of the physical state of a system). The second phenomenon is information as the observer’s knowledge about the system. This is an epistemic phenomenon, existing only relative to an observer. The proposed term is “observer’s knowledge” (information in the sense of the description accessible to an observer). The third phenomenon is information as an independent physical entity (Wheeler’s “It from Bit” thesis). This is a metaphysical construct lacking a rigorous physical definition. The author proposes calling it “pseudosubstance” (information in the sense of an independent ontological entity) and notes that in serious physical discourse this term should not be used as a working concept. The proposed terminology eliminates ambiguity, makes pseudo‑problems disappear, and returns physics to its foundations — the description of physical objects, not of “information” as a separate entity. During a transitional period, it is recommended to use constructions with parenthetical explanations: “configuration (information in the sense of the physical state of a system)”. The author invites the scientific community to discuss these proposals. Keywords: information, terminology, configuration, observer’s knowledge, pseudosubstance, information paradox.
What is information? A short answer could be: Anything that changes our minds and states of thinking! Information is virtual. It can be carried by speech, an image, scratches on a stone, patterns in a photon field, the connections of neurons in our brains or even by the wavefunction of an electron. Information does not depend on the actual means of transmission nor does its identity change when changing the carrier. Information is physical. It needs to be sustained by a physical substrate and rearranging that substrate to contain the wanted information requires to spend energy or work. Without a physical world, information can not be stored, processed, or transmitted. Our world is permeated with different representations of information. Actually Information about the physical laws governing our Universe can be found everywhere and in everything. Could it then be that the real fundamental elements of this world are tiny bits of information? Could we get it from bit?1 A number of researcher investigate this possibility, and several of their attempts to recover physical laws from the principles governing information are reported about in this special issue on physics of information. The articles by Gregg Jaeger,2 by Ariel Caticha,3 and by John Skilling and Kevin Knuth4 address the reconstruction of quantum mechanics from information theory. Furthermore, Kevin Knuth and James Walsh5 show how to recover space-time from particles sending each others signals in an initially geometry-free setting. A central element of most works on information is the concept of a probability. Probabilities can be defined via various routes. Most familiar might be their definitions by the frequentists school as relative frequencies of events (in the limit of infinite amounts of such). A more general definition of probabilities is the Bayesians' one, which regards probabilities as quantifiers of statements, expressing how much those should be expected to be true. Although this definition looks subjective on the first glance, it rests on a solid mathematical theorem by Richard Cox6 that any extension of binary logic to a continuum of single valued truthfulness quantifier that respects a minimum of requirements must be isomorphic to probability theory. And this definition turns out to embrace the frequentists' definition in case that infinite numbers of comparable events are actually available and can be counted. The majority of authors of this special issues seem to favor the Bayesian perspective, which is probably a result of our own, the guest editors', preference and not necessarily a reflection of the prevailing position of contemporary scientists. The different views on probabilities of frequentists and Bayesians are addressed by the article of Allen Caldwell.7 He builds a bridge between these antagonistic camps by explaining frequentists' constructions in a Bayesian language. In particular, his argumentation why the omnipresent p-value in statistical and experimental literature might often capture a relevant signal of model misfit is reassuring, given that a large fraction of our medical system is based on decisions backed up by p-values. A Bayesian might add that it would be even more reassuring, if a system rigorously build on logic and its continuous extension would be used for decisions affecting live-or-death questions. The laws governing probabilities themselves seem to reflect that of more elementary mathematical structures. Kevin Knuth shows how these emerge from lattice theory, which deals with relations in partially ordered sets like that of collections of possibilities.8 The sum rule of probability theory is a direct consequence of the underlying lattice structure. Interestingly, a number of other theories are resting also on such lattices and therefore exhibit their own versions of sum rules: measures of sets, mutual information, the Euler characteristics of topological spaces, as well as quantum mechanical interactions that are quantified by pairs of numbers, the real and imaginary parts of complex probability amplitudes (see also4). The theory of information has very practical application in physics and elsewhere. Manfred Opper discusses how the solutions of stochastic differential equations can be inferred via variational methods, which have their origin in thermodynamics.9 Torsten Enßlin introduces information field theory (IFT), the information theory for fields, as a means to infer the configuration of a physical field from incomplete and noisy data.10 The mathematical apparatus for this is that of quantum field theory (QFT), just with ordinary probabilities instead of complex probability amplitudes as in the latter. Could it be that the difference between IFT and QFT is just be the same as between classical information theory and quantum mechanics, the transition from real valued to complex valued quantifier for statements? Anyhow, any practical inference machinery, be it for dynamical systems or for fields, requires sophisticated numerical methods. Michael Betancourt reviews Markov Chain Monte Carlo Methods to calculate expectation values over high dimensional probabilities.11 Theo Steininger and coworkers present the NIFTy3 software package for numerical information field theory calculations, which can handle very high dimensional field inference problems.12 Finally, in an article focused on the subtleties of the Monty Hall problem and mostly aiming at information theoretical entertainment, Torsten Enßlin and Margret Westercamp investigate the possibility that human intuition might be more rational than contemporary psychology thinks.13 A number of possible topics for an issue on physics of information are not addressed here. We would have loved to have articles on Landauer's principle, which states that erasing information has to cost energy, on QBism, a Bayesian version of quantum mechanics, on artificial and biological neural networks, as well as any other aspect of the information-soaked biological world. What has a reader of this special issue to be equipped with in order to follow the lines of thoughts? In addition to the usual physicist's education, the minimal additional equipment are the basics of probability theory and the concept of entropy. Most of the other concepts used in the articles rest on those and are introduced there. Let A, B, and C be propositions (or possibilities). The probability P ( A | B ) of A being true assuming that B is true is a number between 0 and 1, with P ( A | B ) = 1 expressing certainty of A under B ( B ⇒ A ) and P ( A | B ) = 0 expressing certainty of not A being the case under B ( B ⇒ ¬ A ).
Introduction Does Schrödinger's wave function describe physical reality (“it” in John Wheeler's terminology (Wheeler 1994)) or some kind of information (“bit”)? The answer to this question must crucially depend on the definition of these terms. Is it then merely a matter of words? Not quite – I feel. Inappropriate words may be misleading, while reasonably chosen terms are helpful. A bit is usually understood as the binary unit of information, which can be physically realized in (classical) computers, but also by neuronal states of having fired or not. This traditional physical (in particular, thermodynamical) realization of information (“bit from it”) has proven essential in order to avoid paradoxes otherwise arising from situations related to Maxwell's demon. On the other hand, the concept of a bit has a typical quantum aspect: the very word quantum refers to discreteness, while, paradoxically, the quantum bit is represented by a continuum (the unit sphere in a two-dimensional Hilbert space) – more similar to an analog computer. If this quantum state describes “mere information,” how can there be real quantum computers that are based on such superpositions of classical bits? The problematic choice of words characterizing the nature of the wave function (or a general “quantum state”) seems to reflect the common uneasiness of physicists, including the founders of quantum theory, about its fundamental meaning. However, it may also express a certain prejudice.
This article analyses the so‑called “black hole information paradox” — one of the most discussed problems in modern theoretical physics. It is shown that the paradox arises only within the framework of “informational language”, where the word “information” is used in three different senses that become conflated. A distinction is introduced between the ontic (the physical configuration of the system, existing independently of any observer) and the epistemic (the observer’s knowledge about the system). A simple description of Hawking radiation is given: quantum fluctuations near the horizon of a collapsar produce pairs of particles; one falls inward, the other escapes, creating the appearance of evaporation. Based on this distinction, a reformulation of the problem is proposed in terms of physical objects without the ontologised concept of “information”. In this reformulation, a collapsar (so‑called “black hole”) is a compact massive object into whose gravitational capture zone physical systems are drawn. Crossing the event horizon means an epistemic loss (the observer ceases to know the configuration), not an ontological destruction. The unitarity of quantum mechanics is not violated because the total quantum state of the system evolves reversibly. The main counter‑arguments (the firewall paradox, the unproven status of correlations in Hawking radiation) are examined and answered. It is shown that the “information paradox” disappears, leaving a technical problem of describing quantum correlations. This article is the first in the series “Reformulating Key Concepts of Physics Without Informational Language”. Keywords: collapsar, information paradox, ontic, epistemic, configuration, observer’s knowledge.
Quantum mechanics was reformulated as an information theory involving a generalized kind of information, namely quantum information, in the end of the last century. Quantum mechanics is the most fundamental physical theory referring to all claiming to be physical. Any physical entity turns out to be quantum information in the final analysis. A quantum bit is the unit of quantum information, and it is a generalization of the unit of classical information, a bit, as well as the quantum information itself is a generalization of classical information. Classical information refers to finite series or sets while quantum information, to infinite ones. Quantum information as well as classical information is a dimensionless quantity. Quantum information can be considered as a “bridge” between the mathematical and physical. The standard and common scientific epistemology grants the gap between the mathematical models and physical reality. The conception of truth as adequacy is what is able to transfer “over” that gap. One should explain how quantum information being a continuous transition between the physical and mathematical may refer to truth as adequacy and thus to the usual scientific epistemology and methodology. If it is the overall substance of anything claiming to be physical, one can question how different and dimensional physical quantities appear. Quantum information can be discussed as the counterpart of action. Quantum information is what is conserved, action is what is changed in virtue of the fundamental theorems of Emmy Noether (1918). The gap between mathematical models and physical reality, needing truth as adequacy to be overcome, is substituted by the openness of choice. That openness in turn can be interpreted as the openness of the present as a different concept of truth recollecting Heidegger’s one as “unconcealment” (ἀλήθεια). Quantum information as what is conserved can be thought as the conservation of that openness