**1. Introduction**

In this paper, we study information that is defined as physical concrete phenomena. We also discuss its properties, and its relation to abstract concepts of information. This section presents the background to this study, the justification for undertaking it, and its potential benefits. This section also introduces some basic terms used within the paper.

The various definitions of information range from abstract notions of knowledge, messages, symbols, and signals [1–7], through to more physical notions as objective phenomena [8–11], and on to more quantified concepts—often expressing information as a series of bits [5,11–16].<sup>1</sup> It seems, however, that most concepts of information can be subsumed under two broad categories.<sup>2</sup>

In the first category, we bring together concepts that present information as something abstract, while in the second category, we can gather concepts that define information as a concrete physical phenomenon.

Information in the first category is presented as an abstract concept, therefore, we denote it as information A, where the "A" represents "abstract".<sup>3</sup> In some definitions, information A results from a human agent's interaction with nature [17]. In some other definitions, information A may result from the cognitive activity of some non-human organism [18–20] or even some artificially intelligent agen<sup>t</sup> [21,22]. However, in other cases, information A is claimed to exist independently in some world of ideas [23], or in other cases, information A may be seen through semiotic concepts [24]. Yet others claim that this information is data, or at least derived from data; from this perspective, the boundary between data and information A is quite fluid [4,5,25–30]. To many authors, information A is the prevalent conceptualization of information, and when they write about information, they claim that this is what information is really like [5,14,22,31–39] (note that this list is by necessity selective, and therefore incomplete).

<sup>1</sup> Mark Burgin [14,16] lists 32 mathematical formulas for information.

<sup>2</sup> We acknowledge that a generalization like this will never be 100% accurate, therefore some concepts of information may not fit into either of these two categories, or they may, in some sense, belong to both.

<sup>3</sup> By "abstract," we refer to something not existing in space-time as a physical object.

In the second category, information is regarded as a physical phenomenon, so we denote it as informationC, where the "C" represents "concrete".<sup>4</sup> As informationC is a physical object or phenomenon, it can be measured and quantified, transformed, observed, and used. In this sense, such information is a property of matter and the physical world, and some claim it is the third constituent element of reality (e.g., [9]). InformationC relates to the organization of nature, from the sub-atomic level to large-scale objects, from particles to cosmic bodies [40]. Authors who recognize the existence of physical information and its function in nature include the likes of von Weizsäcker [41], Turek [8], Hidalgo [10], Rovelli [11], Nagel [17], Devlin [34], Heller [42,43], Collier [44], Stonier [45], Polkinghorne [46], Seife [47], Schroeder [48,49], Dodig Crnkovic [50], Wilczek [51], Carroll [52], Davies [53], and Sole and Elena [54]. (As before, the list is by necessity selective and incomplete.) Table 1 below summarizes the main properties of informationA and informationC.



This study focuses on the second category of information, namely, informationC, and discusses how the existence<sup>5</sup> of this information is recognized, the properties that can be attributed to it, and its relationship to informationA (see also Krzanowski [55]).<sup>6</sup> But why is the concept of informationC so important, at least to the author? With the multiple definitions and classifications for information, our understanding of it resembles the parable of the blind men studying an elephant (Shah [56]): We each know a part of the investigated object, but not the whole. The hope is that the concept of informationC may unify our view of information or put it in some order. Unifying the different concepts will further our understanding of reality and increase our recognition of its complexity and coherence, and such things are worth pursuing in their own right. That is why we search for a Grand Unified Theory (GUT) or a Theory of Everything (ToE).

Is informationC a completely novel idea, though? Well, yes and no. On the one hand, the concept of information as a physical phenomenon is certainly not new. Information as a physical entity in various forms has been proposed by many authors (as mentioned above). On the other hand, no comprehensive study has investigated what the concept of informationC entails or how it should be interpreted. This study, therefore, attempts to fill this gap.

In the following discussion, we first present how information as a physical phenomenon may be recognized and comprehended. The cited authors have supplied a short list of features that ground

<sup>4</sup> By "concrete", we mean existing in space and time as a physical object.

<sup>5</sup> In all cases of information, though, how can we say that both kinds of information exist? After all, the statement about how informationA "exists" is not compatible with the statement about how informationC "exists". The concept of existence in the case of information is discussed later in the study.

<sup>6</sup> InformationA and informationC have many interpretations that vary depending on what a specific author regards as concrete or abstract, so this division into two basic classes of information is certainly a generalization. There are also proposals for combining abstract and physical aspects into some sort of unified form of information. One example of this is Rovelli's purely physical meaningful information (i.e., physical information with meaning). We could denote such information as informationAC. The concept of informationAC is not discussed here any further, however, but more details can be found in Rovelli's paper (Rovelli [11], Krzanowski [55]). Something worth noting, however, is that a concrete-abstract combination is only plausible after significantly changing the meaning of its component terms. In Rovelli's case, the concept of meaning (i.e., abstract knowledge) is reworked. In addition, the suggested resolution by Rovelli for the concrete–abstract concept of information has little to do with the general abstract–concrete problem of metaphysics [57,58]; Rovelli's proposal specifically addresses the concept of information, but it does not resolve the metaphysical abstract–concrete division.

the claims of this phenomenon's existence in physical facts. We then focus on three characteristics of information as a physical entity, although these characteristics are not necessarily novel, however, because every physical phenomenon must, by definition, possess some of these properties (see also [57–59]).<sup>7</sup> The question then is, therefore, one of whether we can attribute these features to information, not one of whether these features have been correctly chosen. Next, we look at the dependency between informationC and information A. We then propose that information A can be derived from informationC, but information A cannot be simply reduced to informationC. In the final section, we summarize the main points of this paper and present some problems that have been indicated for informationC, but left unresolved in the reviewed studies.

When we talk about concrete information (informationC) in this paper, we may use the term interchangeably with other terms like objective information (i.e., information that exists objectively) or physical information (i.e., information as a part of physical reality), or we may follow Rovelli's example of purely physical information (i.e., equivalent to physical information). Likewise, when we talk about abstract information (information A), we may use the term interchangeably with similar terms like subjective information (i.e., information that depends upon a cognitive agent), epistemic information (i.e., information related to knowledge), and meaningful information (i.e., information conveying meaning). Finally, the generic term "information" is used to denote any specific concept that must be qualified according to a context or a descriptive term, otherwise it is devoid of meaning. In addition, when we talk about an object, we are referring to something that exists in physical reality.

#### **2. Is InformationC a Physical Phenomenon?**

This section seeks to answer the following questions: Why do we claim that information is a physical phenomenon? Are there natural phenomena that we can class as information?

The concept of information is always associated with form, structure, or organization in some way. For example, information A represents meaning that a cognitive agen<sup>t</sup> has associated with the form, structure, or organization of some entity. InformationC, in contrast, recognizes the form, structure, or organization of some entity as a purely physical phenomenon in itself. But what are the consequences of saying that informationC is a physical phenomenon? It essentially means that informationC is an irreducible aspect of physical reality. InformationC is therefore not like a rainbow or a temperature of a volume of gas8. Instead, informationC exhibits properties that we attribute to physical entities, namely, that (a) it is observable, (b) it is ontologically objective, (c) it can be manipulated, (d) it has no meaning, and I it can be quantified or measured.<sup>9</sup> InformationC exists wherever physical reality exists, just like other physical phenomena. Information as a physical phenomenon that exists objectively has been recognized in the studies of, for example, Mynarski [9], Rovelli [11], Devlin [34], Heller [42,43], Collier [44], Stonier [45], Polkinghorne [46], Seife [47], Caroll [52], Dodig Crnkovic [50,60], and Dodig Crnkovic, Muller and Burgin [61]. Furthermore, Hidalgo [10], Stonier [45], and Seife [47], among others, posited that this information can be manipulated. VonWeizsäcker [41], Seife [47], Carroll [52], Stonier [45], Hidalgo [10], and Collier [44], meanwhile, recognized that this information is not associated with any meaning, and this observation has been confirmed in many other studies. In addition, the studies of von Weizsäcker [41], Barrow [62], Davies [53], Sole and Elena [54], and Heller [42,43] demonstrated that this information can be quantified. Thus, informationC is not conceptualized as an abstract concept in the way that mathematical objects, ideas, or thoughts are abstract (i.e., they exist outside of space and time). Therefore, informationC also does not belong to the

<sup>7</sup> The general features that characterize a physical phenomenon are often disputed, so we follow the most prevalent views on scientific realism [59].

<sup>8</sup> A rainbow and a temperature of a volume of gas are physically reducible to (can be explained by) more fundamental phenomena: white light refraction and the average kinetic energy of gas molecules, respectively.

<sup>9</sup> For more about the conditions for attributing ontology to a physical phenomenon, see the works of Worrall [59], Klee [63], Chakravartty [64], and Liston [65]. We bypass the discussion between the scientific realists and the anti-realists and assume the first position.

Platonic realm of Forms in either the old- or neo-Platonic sense (there will be more about informationC and Plato's Forms later in the study). InformationC is a natural phenomenon, and therefore, contained within nature, just as every physical object is (see also [63–65]).

To avoid making any unfounded claims, we state that informationC must always exist within a physical medium (i.e., it cannot exist on its own). In other words, it is not something existing outside of physical objects, like Forms in Plato's Theory of Forms, but rather a part of physical reality.<sup>10</sup> From this perspective, informationC is the third constituent element of nature [9,34,47], with the first two being energy and matter. This perspective, therefore, excludes any conceptualization of informationC as something mysterious or esoteric or any other form of magical phenomenon hitching a ride on a physical medium.<sup>11</sup> What is more, we also prevent anyone from associating this information with some structure that overlays physical objects, as was suggested by Bates [66], Dinneen and Brauner [67], and in some sense Von Weizsäcker [41].

We now ask another question: What properties should we assign to informationC, and how should we interpret these properties?

## **3. Three Features of InformationC**

When information is defined as a physical phenomenon, it has to have properties in common with other physical entities, namely, the ones that make them physical phenomena (e.g., Worrall [59], Klee [63], Chakravartty [64], Liston [65]). In addition, informationC has a property that makes it a phenomenon in its own right. These properties are discussed below.

We posit that informationC (1) exists objectively, (2) lacks meaning, and (3) expresses the organization or form of physical objects (we will further explain this last claim later on). We posit that we need all three of these features to describe informationC. First, objective existence alone is insu fficient to uniquely characterize physical information, because everything in the real world exists objectively. The same applies to the lack of meaning and the presence of some organization when considered separately.<sup>12</sup> Any combination of two of the three features (e.g., lack of meaning with objectivity, organization with objectivity, etc.) is also not specific enough. Only the combination of these three features is su fficient to make informationC a distinguishable physical phenomenon, so all three features are needed to adequately describe informationC. We do not claim that informationC has only these features. But we only claim, based on our current understanding of informationC these three features are su fficient to characterize it. It is possible that, in the future, this set of properties may change.
