Recent from talks
Contribute something
Nothing was collected or created yet.
Information
View on Wikipedia
| Communication |
|---|
| General aspects |
| Fields |
| Disciplines |
| Categories |
Information is an abstract concept that refers to something which has the power to inform. At the most fundamental level, it pertains to the interpretation (perhaps formally) of that which may be sensed, or their abstractions. Any natural process that is not completely random and any observable pattern in any medium can be said to convey some amount of information. Whereas digital signals and other data use discrete signs to convey information, other phenomena and artifacts such as analogue signals, poems, pictures, music or other sounds, and currents convey information in a more continuous form.[1] Information is not knowledge itself, but the meaning that may be derived from a representation through interpretation.[2]
The concept of information is relevant or connected to various concepts,[3] including constraint, communication, control, data, form, education, knowledge, meaning, understanding, mental stimuli, pattern, perception, proposition, representation, and entropy.
Information is often processed iteratively: Data available at one step are processed into information to be interpreted and processed at the next step. For example, in written text each symbol or letter conveys information relevant to the word it is part of, each word conveys information relevant to the phrase it is part of, each phrase conveys information relevant to the sentence it is part of, and so on until at the final step information is interpreted and becomes knowledge in a given domain. In a digital signal, bits may be interpreted into the symbols, letters, numbers, or structures that convey the information available at the next level up. The key characteristic of information is that it is subject to interpretation and processing.
The derivation of information from a signal or message may be thought of as the resolution of ambiguity or uncertainty that arises during the interpretation of patterns within the signal or message.[4]
Information may be structured as data. Redundant data can be compressed up to an optimal size, which is the theoretical limit of compression.
The information available through a collection of data may be derived by analysis. For example, a restaurant collects data from every customer order. That information may be analyzed to produce knowledge that is put to use when the business subsequently wants to identify the most popular or least popular dish.[citation needed]
Information can be transmitted in time, via data storage, and space, via communication and telecommunication.[5] Information is expressed either as the content of a message or through direct or indirect observation. That which is perceived can be construed as a message in its own right, and in that sense, all information is always conveyed as the content of a message.
Information can be encoded into various forms for transmission and interpretation (for example, information may be encoded into a sequence of signs, or transmitted via a signal). It can also be encrypted for safe storage and communication.
The uncertainty of an event is measured by its probability of occurrence. Uncertainty is proportional to the negative logarithm of the probability of occurrence. Information theory takes advantage of this by concluding that more uncertain events require more information to resolve their uncertainty. The bit is a typical unit of information. It is 'that which reduces uncertainty by half'.[6] Other units such as the nat may be used. For example, the information encoded in one "fair" coin flip is log2(2/1) = 1 bit, and in two fair coin flips is log2(4/1) = 2 bits. A 2011 Science article estimates that 97% of technologically stored information was already in digital bits in 2007 and that the year 2002 was the beginning of the digital age for information storage (with digital storage capacity bypassing analogue for the first time).[7]
Etymology and history of the concept
[edit]This section has multiple issues. Please help improve it or discuss these issues on the talk page. (Learn how and when to remove these messages)
|
The English word "information" comes from Middle French enformacion/informacion/information 'a criminal investigation' and its etymon, Latin informatiō(n) 'conception, teaching, creation'.[8]
In English, "information" is an uncountable mass noun.
References on "formation or molding of the mind or character, training, instruction, teaching" date from the 14th century in both English (according to Oxford English Dictionary) and other European languages. In the transition from Middle Ages to Modernity the use of the concept of information reflected a fundamental turn in epistemological basis – from "giving a (substantial) form to matter" to "communicating something to someone". Peters (1988, pp. 12–13) concludes:
- Information was readily deployed in empiricist psychology (though it played a less important role than other words such as impression or idea) because it seemed to describe the mechanics of sensation: objects in the world inform the senses. But sensation is entirely different from "form" – the one is sensual, the other intellectual; the one is subjective, the other objective. My sensation of things is fleeting, elusive, and idiosyncratic. For Hume, especially, sensory experience is a swirl of impressions cut off from any sure link to the real world... In any case, the empiricist problematic was how the mind is informed by sensations of the world. At first informed meant shaped by; later it came to mean received reports from. As its site of action drifted from cosmos to consciousness, the term's sense shifted from unities (Aristotle's forms) to units (of sensation). Information came less and less to refer to internal ordering or formation, since empiricism allowed for no preexisting intellectual forms outside of sensation itself. Instead, information came to refer to the fragmentary, fluctuating, haphazard stuff of sense. Information, like the early modern worldview in general, shifted from a divinely ordered cosmos to a system governed by the motion of corpuscles. Under the tutelage of empiricism, information gradually moved from structure to stuff, from form to substance, from intellectual order to sensory impulses.[9]
In the modern era, the most important influence on the concept of information is derived from the Information theory developed by Claude Shannon and others. This theory, however, reflects a fundamental contradiction. Northrup (1993)[10] wrote:
- Thus, actually two conflicting metaphors are being used: The well-known metaphor of information as a quantity, like water in the water-pipe, is at work, but so is a second metaphor, that of information as a choice, a choice made by :an information provider, and a forced choice made by an :information receiver. Actually, the second metaphor implies that the information sent isn't necessarily equal to the information received, because any choice implies a comparison with a list of possibilities, i.e., a list of possible meanings. Here, meaning is involved, thus spoiling the idea of information as a pure "Ding an sich." Thus, much of the confusion regarding the concept of information seems to be related to the basic confusion of metaphors in Shannon's theory: is information an autonomous quantity, or is information always per SE information to an observer? Actually, I don't think that Shannon himself chose one of the two definitions. Logically speaking, his theory implied information as a subjective phenomenon. But this had so wide-ranging epistemological impacts that Shannon didn't seem to fully realize this logical fact. Consequently, he continued to use metaphors about information as if it were an objective substance. This is the basic, inherent contradiction in Shannon's information theory." (Northrup, 1993, p. 5)
In their seminal book The Study of Information: Interdisciplinary Messages,[11] Almach and Mansfield (1983) collected key views on the interdisciplinary controversy in computer science, artificial intelligence, library and information science, linguistics, psychology, and physics, as well as in the social sciences. Almach (1983,[12] p. 660) himself disagrees with the use of the concept of information in the context of signal transmission, the basic senses of information in his view all referring "to telling something or to the something that is being told. Information is addressed to human minds and is received by human minds." All other senses, including its use with regard to nonhuman organisms as well to society as a whole, are, according to Machlup, metaphoric and, as in the case of cybernetics, anthropomorphic.
Hjørland (2007) [13] describes the fundamental difference between objective and subjective views of information and argues that the subjective view has been supported by, among others, Bateson,[14] Yovits,[15][16] Span-Hansen,[17] Brier,[18] Buckland,[19] Goguen,[20] and Hjørland.[21] Hjørland provided the following example:
- A stone on a field could contain different information for different people (or from one situation to another). It is not possible for information systems to map all the stone's possible information for every individual. Nor is any one mapping the one "true" mapping. But people have different educational backgrounds and play different roles in the division of labor in society. A stone in a field represents typical one kind of information for the geologist, another for the archaeologist. The information from the stone can be mapped into different collective knowledge structures produced by e.g. geology and archaeology. Information can be identified, described, represented in information systems for different domains of knowledge. Of course, there are much uncertainty and many and difficult problems in determining whether a thing is informative or not for a domain. Some domains have high degree of consensus and rather explicit criteria of relevance. Other domains have different, conflicting paradigms, each containing its own more or less implicate view of the informativeness of different kinds of information sources. (Hjørland, 1997, p. 111, emphasis in original).
Information theory
[edit]Information theory is the scientific study of the quantification, storage, and communication of information. The field itself was fundamentally established by the work of Claude Shannon in the 1940s, with earlier contributions by Harry Nyquist and Ralph Hartley in the 1920s.[22][23] The field is at the intersection of probability theory, statistics, computer science, statistical mechanics, information engineering, and electrical engineering.
A key measure in information theory is entropy. Entropy quantifies the amount of uncertainty involved in the value of a random variable or the outcome of a random process. For example, identifying the outcome of a fair coin flip (with two equally likely outcomes) provides less information (lower entropy) than specifying the outcome from a roll of a die (with six equally likely outcomes). Some other important measures in information theory are mutual information, channel capacity, error exponents, and relative entropy. Important sub-fields of information theory include source coding, algorithmic complexity theory, algorithmic information theory, and information-theoretic security.[citation needed]
Applications of fundamental topics of information theory include source coding/data compression (e.g. for ZIP files), and channel coding/error detection and correction (e.g. for DSL). Its impact has been crucial to the success of the Voyager missions to deep space, the invention of the compact disc, the feasibility of mobile phones and the development of the Internet. The theory has also found applications in other areas, including statistical inference,[24] cryptography, neurobiology,[25] perception,[26] linguistics, the evolution[27] and function[28] of molecular codes (bioinformatics), thermal physics,[29] quantum computing, black holes, information retrieval, intelligence gathering, plagiarism detection,[30] pattern recognition, anomaly detection[31] and even art creation.
As sensory input
[edit]Often information can be viewed as a type of input to an organism or system. Inputs are of two kinds. Some inputs are important to the function of the organism (for example, food) or system (energy) by themselves. In his book Sensory Ecology[32] biophysicist David B. Dusenbery called these causal inputs. Other inputs (information) are important only because they are associated with causal inputs and can be used to predict the occurrence of a causal input at a later time (and perhaps another place). Some information is important because of association with other information but eventually there must be a connection to a causal input.
In practice, information is usually carried by weak stimuli that must be detected by specialized sensory systems and amplified by energy inputs before they can be functional to the organism or system. For example, light is mainly (but not only, e.g. plants can grow in the direction of the light source) a causal input to plants but for animals it only provides information. The colored light reflected from a flower is too weak for photosynthesis but the visual system of the bee detects it and the bee's nervous system uses the information to guide the bee to the flower, where the bee often finds nectar or pollen, which are causal inputs, a nutritional function.
As an influence that leads to transformation
[edit]Information is any type of pattern that influences the formation or transformation of other patterns.[33][34] In this sense, there is no need for a conscious mind to perceive, much less appreciate, the pattern. Consider, for example, DNA. The sequence of nucleotides is a pattern that influences the formation and development of an organism without any need for a conscious mind. One might argue though that for a human to consciously define a pattern, for example a nucleotide, naturally involves conscious information processing. However, the existence of unicellular and multicellular organisms, with the complex biochemistry that leads, among other events, to the existence of enzymes and polynucleotides that interact maintaining the biological order and participating in the development of multicellular organisms, precedes by millions of years the emergence of human consciousness and the creation of the scientific culture that produced the chemical nomenclature.
Systems theory at times seems to refer to information in this sense, assuming information does not necessarily involve any conscious mind, and patterns circulating (due to feedback) in the system can be called information. In other words, it can be said that information in this sense is something potentially perceived as representation, though not created or presented for that purpose. For example, Gregory Bateson defines "information" as a "difference that makes a difference".[35]
If, however, the premise of "influence" implies that information has been perceived by a conscious mind and also interpreted by it, the specific context associated with this interpretation may cause the transformation of the information into knowledge. Complex definitions of both "information" and "knowledge" make such semantic and logical analysis difficult, but the condition of "transformation" is an important point in the study of information as it relates to knowledge, especially in the business discipline of knowledge management. In this practice, tools and processes are used to assist a knowledge worker in performing research and making decisions, including steps such as:
- Review information to effectively derive value and meaning
- Reference metadata if available
- Establish relevant context, often from many possible contexts
- Derive new knowledge from the information
- Make decisions or recommendations from the resulting knowledge
Stewart (2001) argues that transformation of information into knowledge is critical, lying at the core of value creation and competitive advantage for the modern enterprise.
In a biological framework, Mizraji [36] has described information as an entity emerging from the interaction of patterns with receptor systems (eg: in molecular or neural receptors capable of interacting with specific patterns, information emerges from those interactions). In addition, he has incorporated the idea of "information catalysts", structures where emerging information promotes the transition from pattern recognition to goal-directed action (for example, the specific transformation of a substrate into a product by an enzyme, or auditory reception of words and the production of an oral response)
The Danish Dictionary of Information Terms[37] argues that information only provides an answer to a posed question. Whether the answer provides knowledge depends on the informed person. So a generalized definition of the concept should be: "Information" = An answer to a specific question".
When Marshall McLuhan speaks of media and their effects on human cultures, he refers to the structure of artifacts that in turn shape our behaviors and mindsets. Also, pheromones are often said to be "information" in this sense.
Technologically mediated information
[edit]These sections are using measurements of data rather than information, as information cannot be directly measured.
As of 2007
[edit]It is estimated that the world's technological capacity to store information grew from 2.6 (optimally compressed) exabytes in 1986 – which is the informational equivalent to less than one 730-MB CD-ROM per person (539 MB per person) – to 295 (optimally compressed) exabytes in 2007.[7] This is the informational equivalent of almost 61 CD-ROM per person in 2007.[5]
The world's combined technological capacity to receive information through one-way broadcast networks was the informational equivalent of 174 newspapers per person per day in 2007.[7]
The world's combined effective capacity to exchange information through two-way telecommunication networks was the informational equivalent of 6 newspapers per person per day in 2007.[5]
As of 2007, an estimated 90% of all new information is digital, mostly stored on hard drives.[38]
As of 2020
[edit]The total amount of data created, captured, copied, and consumed globally is forecast to increase rapidly, reaching 64.2 zettabytes in 2020. Over the next five years up to 2025, global data creation is projected to grow to more than 180 zettabytes.[39]
As records
[edit]| Part of a series on |
| Library and information science |
|---|
Records are specialized forms of information. Essentially, records are information produced consciously or as by-products of business activities or transactions and retained because of their value. Primarily, their value is as evidence of the activities of the organization but they may also be retained for their informational value. Sound records management ensures that the integrity of records is preserved for as long as they are required.[citation needed]
The international standard on records management, ISO 15489, defines records as "information created, received, and maintained as evidence and information by an organization or person, in pursuance of legal obligations or in the transaction of business".[40] The International Committee on Archives (ICA) Committee on electronic records defined a record as, "recorded information produced or received in the initiation, conduct or completion of an institutional or individual activity and that comprises content, context and structure sufficient to provide evidence of the activity".[41]
Records may be maintained to retain corporate memory of the organization or to meet legal, fiscal or accountability requirements imposed on the organization. Willis expressed the view that sound management of business records and information delivered "...six key requirements for good corporate governance...transparency; accountability; due process; compliance; meeting statutory and common law requirements; and security of personal and corporate information."[42]
Semiotics
[edit]Michael Buckland has classified "information" in terms of its uses: "information as process", "information as knowledge", and "information as thing".[43]
Beynon-Davies[44][45] explains the multi-faceted concept of information in terms of signs and signal-sign systems. Signs themselves can be considered in terms of four inter-dependent levels, layers or branches of semiotics: pragmatics, semantics, syntax, and empirics. These four layers serve to connect the social world on the one hand with the physical or technical world on the other.
Pragmatics is concerned with the purpose of communication. Pragmatics links the issue of signs with the context within which signs are used. The focus of pragmatics is on the intentions of living agents underlying communicative behaviour. In other words, pragmatics link language to action.
Semantics is concerned with the meaning of a message conveyed in a communicative act. Semantics considers the content of communication. Semantics is the study of the meaning of signs – the association between signs and behaviour. Semantics can be considered as the study of the link between symbols and their referents or concepts – particularly the way that signs relate to human behavior.
Syntax is concerned with the formalism used to represent a message. Syntax as an area studies the form of communication in terms of the logic and grammar of sign systems. Syntax is devoted to the study of the form rather than the content of signs and sign systems.
Nielsen (2008) discusses the relationship between semiotics and information in relation to dictionaries. He introduces the concept of lexicographic information costs and refers to the effort a user of a dictionary must make to first find, and then understand data so that they can generate information.
Communication normally exists within the context of some social situation. The social situation sets the context for the intentions conveyed (pragmatics) and the form of communication. In a communicative situation intentions are expressed through messages that comprise collections of inter-related signs taken from a language mutually understood by the agents involved in the communication. Mutual understanding implies that agents involved understand the chosen language in terms of its agreed syntax and semantics. The sender codes the message in the language and sends the message as signals along some communication channel (empirics). The chosen communication channel has inherent properties that determine outcomes such as the speed at which communication can take place, and over what distance.
Physics and determinacy
[edit]The existence of information about a closed system is a major concept in both classical physics and quantum mechanics, encompassing the ability, real or theoretical, of an agent to predict the future state of a system based on knowledge gathered during its past and present. Determinism is a philosophical theory holding that causal determination can predict all future events,[46] positing a fully predictable universe described by classical physicist Pierre-Simon Laplace as "the effect of its past and the cause of its future".[47]
Quantum physics instead encodes information as a wave function, a mathematical description of a system from which the probabilities of measurement outcomes can be computed. A fundamental feature of quantum theory is that the predictions it makes are probabilistic. Prior to the publication of Bell's theorem, determinists reconciled with this behavior using hidden variable theories, which argued that the information necessary to predict the future of a function must exist, even if it is not accessible for humans, a view expressed by Albert Einstein with the assertion that "God does not play dice".[48]
Modern astronomy cites the mechanical sense of information in the black hole information paradox, positing that, because the complete evaporation of a black hole into Hawking radiation leaves nothing except an expanding cloud of homogeneous particles, this results in the irrecoverability of any information about the matter to have originally crossed the event horizon, violating both classical and quantum assertions against the ability to destroy information.[49][50]
The application of information study
[edit]The information cycle (addressed as a whole or in its distinct components) is of great concern to information technology, information systems, as well as information science. These fields deal with those processes and techniques pertaining to information capture (through sensors) and generation (through computation, formulation or composition), processing (including encoding, encryption, compression, packaging), transmission (including all telecommunication methods), presentation (including visualization / display methods), storage (such as magnetic or optical, including holographic methods), etc.
Information visualization (shortened as InfoVis) depends on the computation and digital representation of data, and assists users in pattern recognition and anomaly detection.
-
Partial map of the Internet, with nodes representing IP addresses
-
Galactic (including dark) matter distribution in a cubic section of the Universe
-
Visual representation of a strange attractor, with converted data of its fractal structure
Information security (shortened as InfoSec) is the ongoing process of exercising due diligence to protect information, and information systems, from unauthorized access, use, disclosure, destruction, modification, disruption or distribution, through algorithms and procedures focused on monitoring and detection, as well as incident response and repair.
Information analysis is the process of inspecting, transforming, and modeling information, by converting raw data into actionable knowledge, in support of the decision-making process.
Information quality (shortened as InfoQ) is the potential of a dataset to achieve a specific (scientific or practical) goal using a given empirical analysis method.
Information communication represents the convergence of informatics, telecommunication and audio-visual media & content.
See also
[edit]- Accuracy and precision
- Complex adaptive system
- Complex system
- Data storage
- Engram
- Free Information Infrastructure
- Freedom of information
- Informatics
- Information and communication technologies
- Information architecture
- Information broker
- Information continuum
- Information ecology
- Information engineering
- Information geometry
- Information inequity
- Information infrastructure
- Information management
- Information metabolism
- Information overload
- Information quality (InfoQ)
- Information science
- Information sensitivity
- Information technology
- Information theory
- Information warfare
- Infosphere
- Lexicographic information cost
- Library science
- Meme
- Philosophy of information
- Quantum information
- Receiver operating characteristic
- Satisficing
References
[edit]- ^ John B. Anderson; Rolf Johnnesson (1996). Understanding Information Transmission. Ieee Press. ISBN 978-0-471-71120-9.
- ^ Hubert P. Yockey (2005). Information Theory, Evolution, and the Origin of Life. Cambridge University Press. p. 7. ISBN 978-0-511-54643-3.
- ^ Luciano Floridi (2010). Information – A Very Short Introduction. Oxford University Press. ISBN 978-0-19-160954-1.
- ^ Webler, Forrest (25 February 2022). "Measurement in the Age of Information". Information. 13 (3): 111. doi:10.3390/info13030111.
- ^ a b c "World_info_capacity_animation". YouTube. 11 June 2011. Archived from the original on 21 December 2021. Retrieved 1 May 2017.
- ^ "DT&SC 4-5: Information Theory Primer, Online Course". YouTube. University of California. 2015.
- ^ a b c Hilbert, Martin; López, Priscila (2011). "The World's Technological Capacity to Store, Communicate, and Compute Information". Science. 332 (6025): 60–65. Bibcode:2011Sci...332...60H. doi:10.1126/science.1200970. PMID 21310967. S2CID 206531385. Free access to the article at martinhilbert.net/WorldInfoCapacity.html
- ^ Oxford English Dictionary, Third Edition, 2009, full text
- ^ Peters, J. D. (1988). Information: Notes Toward a Critical History. Journal of Communication Inquiry, 12, 10-24.
- ^ Qvortrup, L. (1993). The controversy over the concept of information. An overview and a selected and annotated bibliography. Cybernetics & Human Knowing 1(4), 3-24.
- ^ Machlup, Fritz & Una Mansfield (eds.). 1983. The Study of Information: Interdisciplinary Messages. New York: Wiley.
- ^ Machlup, Fritz. 1983. "Semantic Quirks in Studies of Information," pp. 641-71 in Fritz Machlup & Una Mansfield, The Study of Information: Interdisciplinary Messages. New York: Wiley.
- ^ Hjørland, B. (2007). Information: Objective or Subjective/Situational?. Journal of the American Society for Information Science and Technology, 58(10), 1448-1456.
- ^ Bateson, G. (1972). Steps to an ecology of mind. New York: Ballantine.
- ^ Yovits, M.C. (1969). Information science: Toward the development of a true scientific discipline. American Documentation (Vol. 20, pp. 369–376).
- ^ Yovits, M. C. (1975). A theoretical framework for the development of information science. In International Federation for Documentation. Study Committee Research on the Theoretical Basis of Information. Meeting (1974: Moscow) Information science, its scope, objects of research and problems: Collection of papers [presented at the meeting of the FID Study Committee "Research on the Theoretical Basis of Information"] 24–26 April 1974, Moscow (pp. 90–114). FID 530. Moscow: VINITI
- ^ Spang-Hanssen, H. (2001). How to teach about information as related to documentation. Human IT, (1), 125–143. Retrieved May 14, 2007, from http://www.hb.se/bhs/ith/1-01/hsh.htm Archived 2008-02-19 at the Wayback Machine
- ^ Brier, S. (1996). Cybersemiotics: A new interdisciplinary development applied to the problems of knowledge organisation and document retrieval in information science. Journal of Documentation, 52(3), 296–344.
- ^ Buckland, M. (1991). Information and information systems. New York: Greenwood Press.
- ^ Goguen, J. A. (1997). Towards a social, ethical theory of information. In G. Bowker, L. Gasser, L. Star, & W. Turner, Erlbaum (Eds.), Social science research, technical systems and cooperative work: Beyond the great divide (pp. 27–56). Hillsdale, NJ: Erlbaum. Retrieved May 14, 2007, from http://cseweb.ucsd.edu/~goguen/ps/sti.pdf
- ^ Hjørland, B. (1997). Information seeking and subject representation. An activity-theoretical approach to information science. Westport: Greenwood Press.
- ^ Pérez-Montoro Gutiérrez, Mario; Edelstein, Dick (2007). The Phenomenon of Information: A Conceptual Approach to Information Flow. Lanham (Md.): Scarecrow Press. pp. 21–22. ISBN 978-0-8108-5942-5.
- ^ Wesołowski, Krzysztof (2009). Introduction to Digital Communication Systems (PDF) (1. publ ed.). Chichester: Wiley. p. 2. ISBN 978-0-470-98629-5.
- ^ Burnham, K. P. and Anderson D. R. (2002) Model Selection and Multimodel Inference: A Practical Information-Theoretic Approach, Second Edition (Springer Science, New York) ISBN 978-0-387-95364-9.
- ^ F. Rieke; D. Warland; R Ruyter van Steveninck; W Bialek (1997). Spikes: Exploring the Neural Code. The MIT press. ISBN 978-0-262-68108-7.
- ^ Delgado-Bonal, Alfonso; Martín-Torres, Javier (3 November 2016). "Human vision is determined based on information theory". Scientific Reports. 6 (1) 36038. Bibcode:2016NatSR...636038D. doi:10.1038/srep36038. ISSN 2045-2322. PMC 5093619. PMID 27808236.
- ^ cf; Huelsenbeck, J. P.; Ronquist, F.; Nielsen, R.; Bollback, J. P. (2001). "Bayesian inference of phylogeny and its impact on evolutionary biology". Science. 294 (5550): 2310–2314. Bibcode:2001Sci...294.2310H. doi:10.1126/science.1065889. PMID 11743192. S2CID 2138288.
- ^ Allikmets, Rando; Wasserman, Wyeth W.; Hutchinson, Amy; Smallwood, Philip; Nathans, Jeremy; Rogan, Peter K. (1998). "Thomas D. Schneider], Michael Dean (1998) Organization of the ABCR gene: analysis of promoter and splice junction sequences". Gene. 215 (1): 111–122. doi:10.1016/s0378-1119(98)00269-8. PMID 9666097.
- ^ Jaynes, E. T. (1957). "Information Theory and Statistical Mechanics". Phys. Rev. 106 (4): 620. Bibcode:1957PhRv..106..620J. doi:10.1103/physrev.106.620. S2CID 17870175.
- ^ Bennett, Charles H.; Li, Ming; Ma, Bin (2003). "Chain Letters and Evolutionary Histories". Scientific American. 288 (6): 76–81. Bibcode:2003SciAm.288f..76B. doi:10.1038/scientificamerican0603-76. PMID 12764940. Archived from the original on 7 October 2007. Retrieved 11 March 2008.
- ^ David R. Anderson (1 November 2003). "Some background on why people in the empirical sciences may want to better understand the information-theoretic methods" (PDF). Archived from the original (PDF) on 23 July 2011. Retrieved 23 June 2010.
- ^ Dusenbery, David B. (1992). Sensory Ecology. New York: W.H. Freeman. ISBN 978-0-7167-2333-2.
- ^ Shannon, Claude E. (1949). The Mathematical Theory of Communication. Bibcode:1949mtc..book.....S.
- ^ Casagrande, David (1999). "Information as verb: Re-conceptualizing information for cognitive and ecological models" (PDF). Journal of Ecological Anthropology. 3 (1): 4–13. doi:10.5038/2162-4593.3.1.1.
- ^ Bateson, Gregory (1972). Form, Substance, and Difference, in Steps to an Ecology of Mind. University of Chicago Press. pp. 448–466.
- ^ Mizraji, E. (2021). "The biological Maxwell's demons: exploring ideas about the information processing in biological systems". Theory in Biosciences. 140 (3): 307–318. doi:10.1007/s12064-021-00354-6. PMC 8568868. PMID 34449033.
- ^ Simonsen, Bo Krantz. "Informationsordbogen – vis begreb". Informationsordbogen.dk. Retrieved 1 May 2017.
- ^ Failure Trends in a Large Disk Drive Population. Eduardo Pinheiro, Wolf-Dietrich Weber and Luiz Andre Barroso
- ^ "Total data volume worldwide 2010–2025". Statista. Retrieved 6 August 2021.
- ^ ISO 15489
- ^ Committee on Electronic Records (February 1997). "Guide For Managing Electronic Records From An Archival Perspective" (PDF). www.ica.org. International Committee on Archives. p. 22. Retrieved 9 February 2019.
- ^ Willis, Anthony (1 August 2005). "Corporate governance and management of information and records". Records Management Journal. 15 (2): 86–97. doi:10.1108/09565690510614238.
- ^ Buckland, Michael K. (June 1991). "Information as thing". Journal of the American Society for Information Science. 42 (5): 351–360. doi:10.1002/(SICI)1097-4571(199106)42:5<351::AID-ASI5>3.0.CO;2-3.
- ^ Beynon-Davies, P. (2002). Information Systems: an introduction to informatics in Organisations. Basingstoke, UK: Palgrave. ISBN 978-0-333-96390-6.
- ^ Beynon-Davies, P. (2009). Business Information Systems. Basingstoke: Palgrave. ISBN 978-0-230-20368-6.
- ^ Ernest Nagel (1999). "§V: Alternative descriptions of physical state". The Structure of Science: Problems in the Logic of Scientific Explanation (2nd ed.). Hackett. pp. 285–292. ISBN 978-0-915144-71-6.
A theory is deterministic if, and only if, given its state variables for some initial period, the theory logically determines a unique set of values for those variables for any other period.
- ^ Laplace, Pierre Simon, A Philosophical Essay on Probabilities, translated into English from the original French 6th ed. by Truscott, F.W. and Emory, F.L., Dover Publications (New York, 1951) p.4.
- ^ The Collected Papers of Albert Einstein, Volume 15: The Berlin Years: Writings & Correspondence, June 1925-May 1927 (English Translation Supplement), p. 403
- ^ Hawking, Stephen (2006). The Hawking Paradox. Discovery Channel. Archived from the original on 2 August 2013. Retrieved 13 August 2013.
- ^ Overbye, Dennis (12 August 2013). "A Black Hole Mystery Wrapped in a Firewall Paradox". The New York Times. Retrieved 12 August 2013.
Further reading
[edit]- Liu, Alan (2004). The Laws of Cool: Knowledge Work and the Culture of Information. University of Chicago Press.
- Bekenstein, Jacob D. (August 2003). "Information in the holographic universe". Scientific American. 289 (2): 58–65. Bibcode:2003SciAm.289b..58B. doi:10.1038/scientificamerican0803-58. PMID 12884539.
- Gleick, James (2011). The Information: A History, a Theory, a Flood. New York, NY: Pantheon.
- Lin, Shu-Kun (2008). "Gibbs Paradox and the Concepts of Information, Symmetry, Similarity and Their Relationship". Entropy. 10 (1): 1–5. arXiv:0803.2571. Bibcode:2008Entrp..10....1L. doi:10.3390/entropy-e10010001. S2CID 41159530.
- Floridi, Luciano (2005). "Is Information Meaningful Data?" (PDF). Philosophy and Phenomenological Research. 70 (2): 351–370. doi:10.1111/j.1933-1592.2005.tb00531.x. hdl:2299/1825. S2CID 5593220.
- Floridi, Luciano (2005). "Semantic Conceptions of Information". In Zalta, Edward N. (ed.). The Stanford Encyclopedia of Philosophy (Winter 2005 ed.). Metaphysics Research Lab, Stanford University.
- Floridi, Luciano (2010). Information: A Very Short Introduction. Oxford: Oxford University Press.
- Logan, Robert K. What is Information? – Propagating Organization in the Biosphere, the Symbolosphere, the Technosphere and the Econosphere. Toronto: DEMO Publishing.
- Machlup, F. and U. Mansfield, The Study of information : interdisciplinary messages. 1983, New York: Wiley. xxii, 743 p. ISBN 978-0471887171
- Nielsen, Sandro (2008). "The Effect of Lexicographical Information Costs on Dictionary Making and Use". Lexikos. 18: 170–189.
- Stewart, Thomas (2001). Wealth of Knowledge. New York, NY: Doubleday.
- Young, Paul (1987). The Nature of Information. Westport, Ct: Greenwood Publishing Group. ISBN 978-0-275-92698-4.
- Kenett, Ron S.; Shmueli, Galit (2016). Information Quality: The Potential of Data and Analytics to Generate Knowledge. Chichester, United Kingdom: John Wiley and Sons. doi:10.1002/9781118890622. ISBN 978-1-118-87444-8.
External links
[edit]- Semantic Conceptions of Information Review by Luciano Floridi for the Stanford Encyclopedia of Philosophy
- Principia Cybernetica entry on negentropy
- How Much Information? 2003 Archived 7 April 2010 at the Wayback Machine an attempt to estimate how much new information is created each year (study was produced by faculty and students at the School of Information Management and Systems at the University of California at Berkeley)
- (in Danish) Informationsordbogen.dk The Danish Dictionary of Information Terms / Informationsordbogen
Information
View on GrokipediaEtymology and Definitions
Historical origins of the term
The term "information" originates from the Latin noun informātiō (genitive informātiōnis), denoting the process or result of giving form or shape, derived from the verb informāre, a compound of in- ("into") and formāre ("to form" or "to fashion"). This root conveys the act of imparting structure, particularly to the mind or intellect, as in molding ideas or knowledge.[7][8] The word entered Middle English around the late 14th century (circa 1380–1400), borrowed partly from Anglo-Norman and Middle French enformacion or information, which themselves stemmed from the Latin accusative informationem. Initial English usages emphasized instruction, advice, or the communication of formative knowledge, often in contexts of education, training, or moral shaping, as seen in Chaucer's Parlement of Foules (c. 1382), where it refers to imparting concepts or doctrines.[7][8][9] Early senses also included legal or accusatory connotations, such as intelligence used in criminal investigations or charges against an individual, reflecting French legal traditions where information denoted an inquiry or denunciation. By the 15th century, the term broadened to include abstract notions like outlines of ideas, concepts, or systematic doctrines, aligning with scholastic philosophy's emphasis on informātiō as the act of endowing form to matter or thought.[10][8] In classical and medieval philosophy, precursors to the term linked it to notions of eidos (form) in Plato and Aristotle, where informing involved actualizing potential through structure, though the Latin informātiō formalized this in patristic and scholastic texts, such as those by Thomas Aquinas, who used it to describe divine or intellectual formation of the soul. This evolution from concrete shaping to abstract knowledge transmission set the stage for later semantic shifts, uninfluenced by modern quantitative interpretations until the 20th century.[11][12]Core definitions and key distinctions
Information is fundamentally a measure of the reduction in uncertainty regarding the state of a system or the occurrence of an event, enabling more accurate predictions than chance alone would allow.[13] This conception aligns with empirical observations in communication and decision-making, where patterns or signals resolve ambiguity about possible outcomes. In philosophical terms, information represents shareable patterns that convey meaning, distinct from mere randomness or noise, as it structures knowledge transmission between agents.[14][15] In the formal framework of information theory, established by Claude Shannon in 1948, information is quantified as the average surprise or uncertainty in a message source, calculated via the entropy formula , where denotes the probability of each possible message symbol.[6][16] This definition treats information as a probabilistic property of signal selection, emphasizing freedom of choice in encoding possibilities rather than the message's interpretive content or truth value.[16] Shannon's approach operationalizes information for engineering purposes, such as optimizing transmission channels, but deliberately excludes semantics, focusing solely on syntactic structure and statistical correlations.[6] A primary distinction lies between syntactic information, which pertains to the formal arrangement and probability distribution of symbols (as in Shannon's model), and semantic information, which incorporates meaning, context, and referential accuracy to represent real-world states.[6] Syntactic measures, like entropy, remain invariant to whether a signal conveys falsehoods or truths, whereas semantic evaluations assess informativeness based on alignment with verifiable facts, as seen in critiques of Shannon's framework for overlooking causal or epistemic validity.[6] Another key differentiation is between data, information, and knowledge within the DIKW hierarchy. Data consist of raw, uncontextualized symbols, facts, or measurements—such as isolated numerical readings or binary digits—that possess no inherent meaning on their own.[17][18] Information emerges when data are processed, organized, and contextualized to answer specific queries (e.g., who, what, where, when), yielding interpretable insights like "sales dropped 15% in Q3 2023 due to supply disruptions."[19][20] Knowledge extends this by integrating information with experiential understanding and causal reasoning, enabling predictive application or decision-making (e.g., "adjust inventory forecasts using historical patterns to mitigate future disruptions").[19][17] This progression reflects a value-adding transformation, where each level builds causally on the prior, though empirical studies note that not all data yield information, and not all information becomes actionable knowledge without human cognition.[18]Historical Evolution
Pre-modern conceptions
In ancient Greek philosophy, conceptions of what would later be termed information centered on the metaphysical role of form in structuring reality and knowledge. Plato (c. 428–348 BCE) posited eternal Forms or Ideas as transcendent archetypes that particulars imperfectly imitate or participate in, thereby imparting intelligible structure to the chaotic sensible world; this participatory relation prefigures information as the conveyance of essential order from ideal to material domains.[21] Aristotle (384–322 BCE), critiquing Plato's separation of forms, advanced hylomorphism, wherein form (eidos or morphē) informs indeterminate prime matter (hylē), actualizing its potential into concrete substances—such as bronze informed into a statue or biological matter into an organism—thus defining information ontologically as the causal imposition of structure enabling existence and function.[22][23] The Latin term informatio, from informare ("to give form to" or "to shape"), emerged in Roman rhetoric and philosophy, denoting the process of endowing matter, mind, or discourse with form. Cicero (106–43 BCE) employed informatio in contexts of education and oratory to describe the shaping of understanding through communicated ideas, bridging Greek ontology with practical instruction.[11] Early Christian thinkers like Augustine of Hippo (354–430 CE) adapted this, viewing informatio as divine illumination forming the soul toward truth, where scriptural and revelatory content informs human intellect akin to light shaping vision, emphasizing information's teleological role in spiritual cognition over mere empirical data.[24] Medieval scholasticism synthesized Aristotelian hylomorphism with Christian theology, treating information as the intelligible species or forms abstracted by the intellect from sensory particulars. Thomas Aquinas (1225–1274 CE) defined cognitive faculties by their capacity to receive informatio—the extrinsic forms of things impressed on the mind without their material substrate—enabling universal knowledge from individual experiences; for instance, perceiving a tree yields not its matter but its quidditative form, which informs the possible intellect into act.[25][26] This framework, echoed in Albertus Magnus (c. 1200–1280 CE) and Duns Scotus (1266–1308 CE), prioritized causal realism in epistemology, where information's truth derives from correspondence to informed essences rather than subjective interpretation, influencing views of revelation as God's self-informing disclosure.[24][27]Modern formalization (19th-20th century)
In the mid-19th century, George Boole advanced the formalization of logical reasoning through algebraic methods, treating propositions as binary variables amenable to mathematical operations. In his 1847 work The Mathematical Analysis of Logic, Boole proposed representing logical relations via equations, such as x(1 - y) = 0 for "x only if y," enabling the systematic manipulation of symbolic expressions without reliance on linguistic interpretation.[28] This approach, expanded in The Laws of Thought (1854), established logic as a calculus of classes and probabilities, where operations like addition and multiplication correspond to disjunction and conjunction, laying groundwork for discrete symbolic processing of information independent of content.[28] Boole's system quantified logical validity through equation solving, influencing later computational and informational frameworks by demonstrating how information could be encoded and transformed algorithmically. Building on Boolean foundations, Gottlob Frege introduced a comprehensive formal language in Begriffsschrift (1879), the first predicate calculus notation. Frege's two-dimensional diagrammatic script expressed judgments, quantifiers (universal and existential), and inferences via symbols like ⊢ for assertion and nested scopes for scope and binding, allowing precise articulation of complex relations such as ∀x (Fx → Gx).[29] This innovation separated logical form from psychological or natural language associations, formalizing deduction as syntactic rule application and enabling the representation of mathematical truths as pure informational structures. Frege's work highlighted the distinction between sense (Sinn) and reference (Bedeutung) in later writings (1892), underscoring that formal systems capture syntactic information while semantics concerns interpretation, a dichotomy central to subsequent informational theories.[29] Parallel developments in physics provided logarithmic measures akin to informational uncertainty. Ludwig Boltzmann formalized thermodynamic entropy in 1877 as , where is Boltzmann's constant and the number of microstates compatible with a macrostate, quantifying the multiplicity of configurations underlying observable disorder.[30] J. Willard Gibbs refined this in 1902 with the ensemble average , incorporating probabilities over states, which mathematically paralleled later informational entropy despite originating in physical reversibility debates. These formulations treated information implicitly as the resolution of microstate possibilities, influencing quantitative views of uncertainty reduction without direct semantic intent.[30] By the 1920s, telecommunications engineering yielded explicit non-probabilistic metrics for information transmission. Harry Nyquist, in his 1924 paper "Certain Factors Affecting Telegraph Speed," derived that a channel of bandwidth Hz over time seconds supports at most independent pulses, limiting symbol rates and thus informational throughput in noiseless conditions.[31] Ralph Hartley extended this in "Transmission of Information" (1928), defining the quantity of information as , where is the number of equiprobable message alternatives and the base, or equivalently for sequences, with selections from symbols.[32] Hartley's measure emphasized choice resolution over meaning, assuming uniform distributions and focusing on syntactic variety, which provided a direct precursor to capacity bounds in communication systems.[31] These engineering formalisms prioritized efficiency in symbol conveyance, decoupling informational volume from content fidelity and setting the stage for probabilistic generalizations.Post-1940s developments
In 1948, Norbert Wiener published Cybernetics: Or Control and Communication in the Animal and the Machine, establishing cybernetics as the science of control and communication across mechanical, biological, and social systems, with information conceptualized as a quantifiable element enabling feedback loops and adaptive behavior rather than mere data transmission.[33][34] This framework extended the notion of information from static content to dynamic processes governing organization and prediction in complex systems, influencing fields like engineering and early artificial intelligence.[35] The 1950s marked the coalescence of information science as a discipline, spurred by postwar computing advances and the demand for automated literature searching amid exponential growth in scientific publications.[36] The term "information science" appeared in 1955, emphasizing systematic methods for indexing, retrieval, and user-centered processing of recorded knowledge, distinct from librarianship by incorporating operations research and early digital tools.[37] By the 1960s, experimental online retrieval systems, such as those funded by U.S. government programs, demonstrated practical scalability, with prototypes like NASA's RECON (1960s) handling thousands of queries per day and paving the way for database technologies.[38] Philosophical inquiries shifted toward semantic dimensions of information, addressing limitations in purely syntactic measures. In 1953, Yehoshua Bar-Hillel and Rudolf Carnap formulated a probabilistic semantic information measure, defining it as the logical content of statements that reduce uncertainty while incorporating truth and meaningfulness, applied to state-descriptions in empirical languages.[39] Fred Dretske's 1981 work Knowledge and the Flow of Information posited information as nomically necessitated correlations between signals and sources, grounding epistemology in informational causation where true beliefs require informational links to facts.[36] From the 1990s onward, Luciano Floridi systematized the philosophy of information (PI), elevating information to an ontological primitive for analyzing reality, cognition, and ethics. Floridi defined strongly semantic information as well-formed, meaningful, and veridical data in 2004, culminating in his 2011 synthesis viewing the universe as an "infosphere" of informational entities and processes.[40] This approach critiqued reductionist views by integrating levels of abstraction, with applications to digital ethics and the informational basis of life, reflecting information's evolution from a technical metric to a foundational category amid the digital era's data proliferation.[36]Information Theory
Mathematical foundations (Shannon, 1948)
Claude Shannon's seminal paper, "A Mathematical Theory of Communication," published in two parts in the Bell System Technical Journal in July and October 1948, established the quantitative foundations of information theory by modeling communication systems mathematically.[1] Shannon conceptualized a communication system comprising an information source producing symbols from a finite alphabet, a transmitter encoding these into signals, a channel transmitting the signals (potentially with noise), a receiver decoding the signals, and a destination interpreting the message.[1] This framework abstracted away from semantic content, focusing instead on the statistical properties of symbol sequences to measure information as the reduction of uncertainty.[41] Central to Shannon's foundations is the concept of entropy for a discrete random variable with probability mass function , defined as bits per symbol, representing the average uncertainty or information content required to specify the source's output.[1] For a source emitting symbols independently, the entropy scales to , enabling efficient encoding: the source coding theorem states that the minimum average codeword length for uniquely decodable codes approaches bits per symbol as block length increases, provided is finite.[1] Entropy satisfies additivity for independent variables ( if and independent), non-negativity (), and maximization at uniform distribution (, with equality for equiprobable symbols), underscoring its role as a fundamental limit on lossless compression.[1] Extending to noisy channels, Shannon introduced mutual information , quantifying the information about input conveyed by output through a channel with transition probabilities .[1] The channel capacity is the maximum over input distributions, in bits per channel use, serving as the supremum rate for reliable communication: the noisy channel coding theorem asserts that rates below allow arbitrarily low error probability with sufficiently long codes, while rates above do not.[1] For the binary symmetric channel with crossover probability , , where is the binary entropy function.[1] These results derive from combinatorial arguments on typical sequences—those with empirical frequencies close to true probabilities—and large deviation principles, ensuring exponential error decay.[1] Shannon's discrete model initially assumed finite alphabets and memoryless sources but laid groundwork for extensions to continuous cases via differential entropy , though without absolute convergence, emphasizing relative measures like mutual information for capacity.[1] The theory's rigor stems from probabilistic limits rather than constructive codes, later realized by algorithms like Huffman for source coding and Turbo/LDPC for channel coding, validating the foundational bounds empirically.[42] Critically, Shannon's entropy diverges from thermodynamic entropy by lacking units tied to physical states, prioritizing statistical predictability over causal mechanisms in message generation.[41]Central concepts: Entropy and channel capacity
In information theory, entropy quantifies the average uncertainty or information content associated with a random variable representing a message source. Claude Shannon introduced this concept in his 1948 paper "A Mathematical Theory of Communication," defining it as a measure of the expected information produced by a stochastic process.[1] The entropy of a discrete random variable with possible values and probability mass function is given by the formula: measured in bits, where the base-2 logarithm reflects binary choices required to specify an outcome.[1] This logarithmic measure arises from the additivity of information content for independent events and the need to weight rarer outcomes more heavily due to their higher informational value.[1] For a uniform distribution over outcomes, entropy reaches its maximum of bits, indicating maximal uncertainty; conversely, a deterministic outcome yields zero entropy.[1] Conditional entropy extends this to the remaining uncertainty in given knowledge of , computed as .[1] Mutual information then measures the reduction in uncertainty of due to , serving as a foundational metric for dependence between variables.[1] These quantities enable precise analysis of information flow in communication systems, independent of semantic content, focusing solely on probabilistic structure.[1] Channel capacity represents the maximum reliable transmission rate over a communication channel, defined as the supremum of mutual information over all input distributions , normalized per use: .[43] Shannon proved that rates below capacity allow error-free communication with arbitrarily long codes, while exceeding it renders reliable decoding impossible, establishing fundamental limits grounded in noise characteristics.[1] For the additive white Gaussian noise (AWGN) channel, the capacity simplifies to , where is bandwidth in hertz, signal power, and noise power, highlighting the logarithmic scaling with signal-to-noise ratio (SNR).[44] This formula, derived in Shannon's work and later formalized with Hartley, underscores bandwidth and SNR as causal determinants of throughput, with practical engineering optimizing inputs to approach theoretical bounds.[44]Extensions, applications, and critiques
Algorithmic information theory, introduced by Andrey Kolmogorov in 1965, extends Shannon's probabilistic framework by quantifying the information content of individual objects rather than ensembles, defining it as the length of the shortest computer program that generates the object—a measure known as Kolmogorov complexity.[45] This approach captures compressibility and randomness intrinsically, independent of probability distributions, and has applications in computability theory and data analysis, though it is uncomputable in general due to the halting problem.[46] Quantum extensions, such as quantum Shannon theory developed since the 1990s, adapt core concepts like entropy and channel capacity to quantum systems, enabling analysis of superposition and entanglement in quantum communication protocols.[47] Information theory underpins data compression algorithms, where Shannon entropy sets the theoretical limit for lossless encoding; for instance, Huffman coding from 1952 assigns shorter codes to more probable symbols, achieving near-entropy rates in practice, as seen in formats like ZIP which reduce file sizes by exploiting redundancy.[48] In cryptography, Shannon's 1949 work established perfect secrecy criteria, proving that the one-time pad requires keys as long as the message for unbreakable encryption under computational unboundedness, influencing modern stream ciphers and key lengths.[49] Error-correcting codes, such as Reed-Solomon used in CDs and QR codes since the 1960s, derive from channel capacity theorems to detect and repair transmission errors up to a fraction of the noise rate.[48] Beyond communications, mutual information quantifies feature relevance in machine learning, powering algorithms like decision trees since the 1980s.[50] Critics argue Shannon's theory neglects semantic meaning, focusing solely on syntactic uncertainty reduction; Shannon himself stated in 1948 that "these semantic aspects of communication are irrelevant to the engineering problem," limiting its scope to quantifiable transmission without addressing interpretation or context.[1] This syntactic emphasis fails to capture "aboutness" or natural meaning in messages, as probabilistic measures like entropy do not distinguish informative content from noise in a semantic sense, prompting proposals for semantic extensions that incorporate receiver knowledge or causal relevance.[51] Despite these limitations, the theory's empirical success in engineering applications demonstrates its robustness for causal prediction of reliable communication, though extensions like algorithmic variants address some individual-sequence shortcomings without resolving uncomputability.[52]Physical Foundations
Thermodynamic links to entropy
The mathematical formulation of entropy in information theory, , introduced by Claude Shannon in 1948, parallels the Gibbs entropy in statistical mechanics, , where is Boltzmann's constant. This similarity reflects Shannon's deliberate analogy to thermodynamic entropy, which quantifies disorder or the multiplicity of microstates, as per Ludwig Boltzmann's 1877 expression for the number of accessible states . However, information entropy remains dimensionless and measures epistemic uncertainty rather than physical disorder, lacking direct units of energy per temperature. The connection manifests physically through the thermodynamics of computation, where handling information alters system entropy. James Clerk Maxwell's 1867 thought experiment of a "demon" that selectively allows fast or slow gas molecules to pass through a door, seemingly decreasing entropy without work input, highlighted tensions between information and the second law of thermodynamics. The paradox arises because the demon exploits knowledge of molecular states to perform sorting, but resolving it requires accounting for the entropy cost of acquiring, storing, and erasing that information. Leo Szilard proposed in 1929 that each measurement yielding one bit of mutual information generates at least of entropy in the measuring apparatus, compensating for any local decrease. Rolf Landauer refined this in 1961, establishing that erasing one bit of information in a computational system—via a logically irreversible process—dissipates at least of energy as heat at temperature , linking logical operations to thermodynamic irreversibility. This bound holds at equilibrium and derives from the second law, as reversible computation avoids erasure but practical systems often incur it. Experimental confirmation came in 2012 using an overdamped colloidal particle in a feedback-controlled double-well potential, where bit erasure dissipated heat matching the Landauer limit of approximately J at room temperature, with excess dissipation attributed to non-equilibrium effects. Further verifications include 2016 single-electron transistor measurements and 2018 quantum bit erasure in superconducting circuits, approaching the bound within factors of 10-100 due to finite-time constraints. Recent 2024-2025 studies in quantum many-body systems have probed the principle under non-equilibrium conditions, affirming its generality. These results underscore that information is physical, with processing inevitably coupled to entropy production, enabling resolutions to demon-like paradoxes through total entropy accounting across system and memory.Information in quantum mechanics
In quantum mechanics, information is fundamentally tied to the probabilistic nature of quantum states, described by density operators rather than classical bit strings. Unlike classical information, which can be perfectly copied and measured without disturbance, quantum information resides in superpositions and entangled states that collapse upon measurement, limiting accessibility and manipulability. This framework emerged from efforts to quantify uncertainty in quantum systems, paralleling Shannon's classical entropy but accounting for non-commutativity and coherence.[53][54] The von Neumann entropy provides a central measure of quantum information content, defined for a density matrix ρ as S(ρ) = -Tr(ρ log₂ ρ), where Tr denotes the trace operation. This entropy quantifies the mixedness or uncertainty of a quantum state, with pure states having zero entropy and maximally mixed states achieving the maximum value log₂ d for a d-dimensional Hilbert space. It extends classical Shannon entropy to quantum systems by incorporating quantum correlations, and its additivity for independent subsystems underpins theorems on compression and distillation of quantum information. For instance, Schumacher's coding theorem establishes that quantum sources can be compressed to their von Neumann entropy rate without loss, mirroring classical results but respecting quantum no-go principles.[53][55] A cornerstone limitation is the no-cloning theorem, which proves that no unitary operation or quantum channel can produce an exact copy of an arbitrary unknown quantum state |ψ⟩ from |ψ⟩ ⊗ |0⟩ to |ψ⟩ ⊗ |ψ⟩. This arises from the linearity of quantum evolution: supposing such a cloner existed would lead to contradictions when applied to superpositions, as cloning α|0⟩ + β|1⟩ would yield inconsistent results compared to cloning basis states separately. The theorem, first rigorously stated in 1982, implies that quantum information cannot be duplicated faithfully, enabling secure protocols like quantum key distribution while prohibiting perfect error correction without additional resources.[56][57] Quantum channels govern information transmission, but Holevo's theorem bounds the classical information extractable from them. For an ensemble of quantum states {p_i, ρ_i} sent through a noiseless channel, the Holevo quantity χ = S(∑ p_i ρ_i) - ∑ p_i S(ρ_i) upper-bounds the mutual information between sender and receiver, showing that n qubits convey at most n classical bits reliably, despite superposition. This limit, derived in 1973, highlights how quantum coherence does not amplify classical capacity without entanglement assistance, distinguishing quantum information processing from naive expectations of exponential gains. Extensions like the Hashing-Squeezing-Wilde theorem further refine capacities for entangled inputs.[58] Entanglement, quantified via measures like entanglement entropy, represents non-local correlations that cannot be simulated classically, forming the basis for quantum advantages in computation and communication. These physical constraints—rooted in unitarity, measurement-induced collapse, and Hilbert space geometry—ensure that information in quantum mechanics is not merely encoded data but an intrinsic property governed by the theory's axioms, with implications for thermodynamics via the quantum second law and black hole information paradoxes.[54][53]Recent quantum information breakthroughs (2020-2025)
In 2020, researchers at the University of Science and Technology of China (USTC) demonstrated quantum advantage using the Jiuzhang photonic quantum processor, which solved a Gaussian boson sampling problem in 200 seconds—a task estimated to take the world's fastest supercomputer 2.5 billion years. This marked an early milestone in photonic quantum information processing, leveraging light-based qubits for specific computational tasks beyond classical simulation. Progress accelerated in quantum error correction (QEC), essential for reliable quantum information storage and manipulation. In December 2024, Google Quantum AI reported below-threshold surface code QEC on its Willow superconducting processor, implementing a distance-7 code with logical error rates suppressed by over an order of magnitude and a distance-5 code sustaining coherence for extended cycles.[59] This breakthrough demonstrated scalable logical qubits, where adding physical qubits reduced errors exponentially, a critical step toward fault-tolerant quantum computing.[59] Building on this, Quantinuum announced in June 2025 the first universal, fully fault-tolerant quantum gate set using trapped-ion qubits, achieving repeatable error correction with logical qubits outperforming physical ones by factors enabling utility-scale applications.[60] IBM outlined a refined roadmap in June 2025 for large-scale fault-tolerant quantum computing, targeting modular architectures with error-corrected logical qubits by 2029, supported by advances in cryogenic scaling and syndrome extraction efficiency.[61] These QEC developments shifted quantum information systems from noisy intermediate-scale quantum (NISQ) devices toward practical utility, with experimental logical qubit lifetimes exceeding physical qubit decoherence times by margins previously unattainable.[61][60] In quantum communication, networks emerged as a parallel frontier. Purdue University established a multi-node quantum network testbed in September 2025, successfully distributing photonic entanglement across nodes for distributed quantum information protocols, enabling experiments in quantum repeaters and secure key distribution.[62] Concurrently, a April 2025 demonstration achieved secure quantum communication over 254 kilometers of deployed telecom fiber using coherence-preserving protocols, minimizing loss and decoherence without dedicated quantum channels.[63] These feats advanced quantum internet prototypes, facilitating entanglement-based information transfer resistant to eavesdropping via quantum no-cloning theorems.[62][63] Google's Willow processor also claimed quantum advantage in 2025 for benchmark tasks, solving problems intractable for classical supercomputers within minutes, corroborated by reduced error rates in random circuit sampling.[64] Overall, these breakthroughs from 2020 to 2025 underscored a transition in quantum information science toward integrated, error-resilient systems, with implications for computation, sensing, and secure networks, though challenges in full scalability persist.[64][65]Biological and Cognitive Contexts
Genetic information and heredity
Genetic information refers to the molecular instructions encoded in deoxyribonucleic acid (DNA) that direct the development, functioning, growth, and reproduction of organisms. DNA consists of two long strands forming a double helix, composed of nucleotide subunits—adenine (A), thymine (T), cytosine (C), and guanine (G)—where A pairs with T and C with G, enabling stable storage and replication of sequence-specific data.[66][67] This sequence specifies the order of amino acids in proteins via the genetic code, a triplet-based system of 64 codons (three-nucleotide combinations) that map to 20 standard amino acids and stop signals, with redundancy but near-universality across life forms.[68] The code's deciphering began with Marshall Nirenberg and Heinrich Matthaei's 1961 cell-free experiment, which demonstrated that synthetic poly-uridine RNA (UUU repeats) directed incorporation of only phenylalanine, establishing UUU as its codon and confirming messenger RNA's role in translation.[68][69] The flow of genetic information follows the central dogma of molecular biology, articulated by Francis Crick in 1958: sequential information transfers unidirectionally from DNA to RNA (transcription) and RNA to protein (translation), excluding reverse flows like protein to DNA under normal conditions.[70] This framework, refined in Crick's 1970 elaboration, underscores DNA's primacy as the heritable repository, with RNA intermediates enabling expression while preventing feedback that could destabilize the code.[71] Deviations, such as reverse transcription in retroviruses, represent exceptions rather than violations, as they still align with nucleic acid-to-nucleic acid transfers.[70] Heredity transmits this information across generations via gametes (sperm and eggs), produced through meiosis—a reductive division that halves the chromosome number (from diploid 2n to haploid n) and introduces variation via crossing over and independent assortment.[72][73] Mitosis, conversely, maintains genetic fidelity in somatic cells by producing identical diploid daughters, supporting organismal development and repair.[72] Fertilization restores diploidy by fusing gametes, recombining parental genomes. Empirical heritability estimates from twin studies—comparing monozygotic (identical) twins sharing 100% DNA versus dizygotic (fraternal) sharing ~50%—reveal genetic factors explain 40-80% of variance in traits like height (h² ≈ 80%), intelligence (h² ≈ 50-70%), and behavioral dispositions, with meta-analyses of over 14 million twin pairs across 17,000 traits confirming broad genetic influence despite environmental modulation.[74][75] These estimates derive from Falconer's formula, h² = 2(r_MZ - r_DZ), where r denotes intraclass correlations, highlighting causal primacy of genes in trait variation while accounting for shared environments.[75] Mutations—sequence alterations via errors in replication or damage—introduce heritable changes, with rates around 10^{-8} to 10^{-9} per base pair per generation in humans, driving evolution but often deleterious due to functional constraints on coding regions.[76]Sensory processing and neural information
Sensory processing converts environmental stimuli into neural signals through transduction in specialized receptor cells, such as photoreceptors in the retina or hair cells in the cochlea, generating graded potentials that trigger action potentials in afferent neurons. These discrete spikes serve as the primary currency of information transmission in the nervous system, propagating along axons to central brain regions for further decoding and integration. Applying information theory, the mutual information between stimulus and response quantifies transmission fidelity as , where denotes entropy, revealing how neural activity reduces uncertainty about the input.[77][78] Neural coding strategies encode stimulus properties via spike patterns: rate coding relies on firing frequency to represent intensity, as seen in muscle spindle afferents signaling stretch magnitude; temporal coding exploits precise spike timing relative to stimulus onset, evident in auditory nerve fibers phase-locking to sound waves up to 4 kHz; and population coding distributes information across neuron groups, with vector summation in motor cortex or orientation tuning in visual cortex. In dynamic sensory environments, such as fly motion detection, single H1 neurons transmit up to 200 bits per second, with each spike contributing independently to stimulus reconstruction, approaching theoretical efficiency bounds under Poisson noise assumptions.[79][78] Experiments in the primary visual cortex (V1) of mammals demonstrate that mutual information between oriented gratings and neuronal responses averages 0.1-0.5 bits per spike for simple cells, increasing with contrast and selectivity, though population codes across dozens of neurons can exceed 10 bits per trial by decorrelating redundant signals. Hierarchical processing from thalamus to cortex filters noise, preserving information despite synaptic unreliability—thalamic relay cells maintain output rates half those of inputs without loss in auditory or somatosensory pathways. However, channel capacity limits arise from spike timing jitter and refractory periods, constraining total throughput to roughly 1-10 bits per neuron per second in peripheral nerves.[80][81][82] Sparse coding optimizes bandwidth in resource-limited systems, as in olfactory bulb mitral cells or retinal ganglion cells, where bursts distinguish signal from noise, transmitting more bits per event than uniform rates; for example, distinguishing single spikes from bursts in multiplexed networks yields higher mutual information under variable stimuli. Redundancy across parallel pathways, like the magnocellular and parvocellular streams in vision, enhances robustness but introduces correlation that information theory analyses must account for via joint entropy to avoid overestimation. These mechanisms ensure causal fidelity from periphery to cortex, though debates persist on whether coding prioritizes efficiency or sparsity for metabolic costs.[83][78]Integrated information and consciousness debates
Integrated Information Theory (IIT), proposed by neuroscientist Giulio Tononi in 2004, posits that consciousness corresponds to the capacity of a system to integrate information, quantified by a measure denoted as Φ (phi), which captures the extent to which a system's causal interactions exceed those of its parts considered independently.[84] In this framework, derived from information-theoretic principles, a system's level of consciousness is determined by the irreducible, intrinsic information it generates through its maximally irreducible conceptual structure, requiring physical rather than merely functional integration.[84] Proponents, including Tononi and collaborator Christof Koch, argue that IIT provides a principled explanation for why specific brain regions, such as the posterior cortex during wakefulness, exhibit high Φ values correlating with conscious states, distinguishing them from unconscious processes like those in cerebellum or deep sleep.[85] Despite its mathematical formalism, IIT faces substantial criticism for lacking robust empirical validation, with studies from 2020 to 2025 indicating weak support for its strong claims compared to rival theories of consciousness.[86] [87] For instance, empirical tests attempting to link Φ to neural activity have yielded mixed results, often supporting only a diluted version of the theory that emphasizes informational complexity without prescribing specific conscious phenomenology.[86] Critics, including neuroscientists like Tim Bayne, challenge IIT's axiomatic foundations—such as the postulate that consciousness is structured and definite—as inadequately justified and potentially unfalsifiable, arguing that the theory's abstract mechanics fail to align with observable neural correlates of consciousness derived from lesion studies or perturbation experiments.[88] Additionally, computational neuroscientists like Joscha Bach highlight that IIT overemphasizes static integration at the expense of dynamic, predictive processing evident in biological cognition, rendering it insufficient for explaining adaptive behaviors tied to awareness.[89] Philosophically, IIT's implications lean toward an emergent form of panpsychism, suggesting that consciousness arises as a fundamental property of sufficiently integrated physical systems, potentially attributing experiential qualities to non-biological entities like grid networks if their Φ exceeds zero.[84] [90] This has drawn objections for exacerbating the "combination problem" of how micro-level conscious elements combine into unified macro-experiences, a issue IIT addresses via causal irreducibility but which skeptics deem circular or empirically untestable.[91] While IIT 4.0, formalized in 2023, refines these concepts to emphasize cause-effect power over repertoire partitions, ongoing debates in 2024–2025 underscore its speculative nature, with limited consensus in neuroscience viewing it as a heuristic rather than a causal account grounded in first-principles mechanisms of neural computation.[92] Recent applications, such as linking posterior parietal cortex integration to conditioning responses, offer tentative support but do not resolve core disputes over sufficiency and falsifiability.[93]Semiotics and Communication
Signs, symbols, and semantic content
In semiotics, signs and symbols serve as vehicles for semantic content, the meaningful interpretation derived from their relation to objects or concepts. A sign is defined as an entity that communicates a meaning distinct from itself to an interpreter, encompassing forms such as words, images, sounds, or objects that acquire significance through contextual investment.[94][95] This process, known as semiosis, generates information by linking perceptible forms to interpretive effects, distinguishing semantic information—tied to meaning and relevance—from purely syntactic measures of signal structure.[96] Charles Sanders Peirce's triadic model structures the sign as comprising a representamen (the sign's form), an object (what it denotes), and an interpretant (the cognitive or pragmatic effect produced).[97] This framework posits that meaning emerges dynamically through the interpretant's mediation, allowing signs to classify as icons (resembling their objects, like photographs), indices (causally linked, such as smoke indicating fire), or symbols (arbitrarily conventional, like words in language). Peirce's approach emphasizes the ongoing, interpretive nature of semiosis, where each interpretant can become a new sign, propagating chains of significance essential for complex information conveyance.[97] Ferdinand de Saussure's dyadic conception contrasts by bifurcating the sign into signifier (the sensory form, e.g., a spoken word) and signified (the associated mental concept), with their union arbitrary and system-dependent.[95] Signification arises from differential relations within a linguistic code, where value derives from contrasts rather than inherent essence, influencing structuralist views of semantic content as relational and conventional.[98] This model highlights how semantic information in human communication relies on shared codes, enabling efficient transmission but vulnerable to misinterpretation absent consensus. Semantic content thus integrates beyond formal syntax, as in Claude Shannon's 1948 information theory, which quantifies message entropy without addressing meaning or truth.[96] Efforts to formalize semantics, such as Yehoshua Bar-Hillel and Rudolf Carnap's 1950s framework, measure informational value via the logical probability of state-descriptions, prioritizing messages that exclude falsehoods and reduce uncertainty about reality.[96] In practice, symbols—predominantly arbitrary signs—dominate cultural and linguistic information systems, their semantic potency rooted in collective habit rather than natural resemblance, underscoring causal realism in how interpretive communities stabilize meaning against noise or ambiguity.Models of information transmission
Claude Shannon introduced the foundational mathematical model for information transmission in his 1948 paper "A Mathematical Theory of Communication," published in the Bell System Technical Journal.[1] This model conceptualizes communication as an engineering problem of reliably sending discrete symbols from a source to a destination over a channel prone to noise, quantifying information as the amount required to reduce uncertainty in the receiver's knowledge of the source's message.[42] Shannon defined information entropy for a discrete source with symbols having probabilities as bits per symbol, representing the average uncertainty or the minimum bits needed for encoding.[1] The core process involves an information source generating a message, which a transmitter encodes into a signal format compatible with the communication channel; the signal travels through the channel, where noise may introduce errors, before a receiver decodes it back into an estimate of the message for the destination.[1] Channel capacity is the maximum mutual information rate over input distributions, ensuring error-free transmission above which reliable communication becomes impossible by the noisy-channel coding theorem.[42] This framework prioritizes syntactic fidelity—accurate symbol reconstruction—over semantic content, treating messages as probabilistic sequences without regard for meaning.[1] Warren Weaver's 1949 interpretation extended Shannon's engineering focus to broader communication problems, adding feedback loops from receiver to transmitter to correct errors iteratively and distinguishing three levels: technical (signal fidelity), semantic (message meaning), and effectiveness (behavioral impact on the receiver).[99] However, the model remains linear and unidirectional in its basic form, assuming passive channels and ignoring interpretive contexts.[100] In semiotic extensions, transmission incorporates signs' triadic structure per Charles Peirce—representamen (sign vehicle), object (referent), and interpretant (meaning effect)—where channel noise affects not just syntax but pragmatic interpretation by the receiver's cultural and experiential fields.[101] Later models, such as Wilbur Schramm's 1954 interactive framework, introduce overlapping "fields of experience" between sender and receiver to account for shared encoding/decoding competencies, enabling feedback and mutual adaptation beyond Shannon's noise-only perturbations.[102] These developments highlight that pure syntactic transmission suffices for digital reliability but fails to capture causal influences of context on informational efficacy in human systems.[52]Human vs. non-human communication systems
Human communication systems, centered on spoken and written language, enable the encoding and transmission of abstract, propositional information across time, space, and contexts, allowing for novel expressions through combinatorial rules.[103] These systems exhibit productivity, where finite elements generate infinite novel utterances, and displacement, referring to non-immediate events or hypothetical scenarios.[104] In contrast, non-human communication, observed in species like primates, birds, and insects, primarily conveys immediate environmental cues such as threats or resources, lacking generative syntax and semantic depth.[105] Linguist Charles Hockett outlined design features distinguishing human language, including duality of patterning—meaningless sounds combine into meaningful units—and cultural transmission via learning rather than instinct alone.[106] Animal systems rarely meet these; for instance, honeybee waggle dances indicate food location and distance but are fixed, non-interchangeable signals not producible or interpretable by all bees equally, and fail to extend to abstract or displaced references.[107] Vervet monkey alarm calls differentiate predators (e.g., leopards vs. eagles) but remain context-bound and non-recursive, without combining to form new meanings.[108] Experiments training apes like chimpanzees with symbols or signs yield rudimentary associations but no evidence of syntactic recursion or infinite productivity, limited to 100-400 symbols without grammatical novelty.[109] Non-human systems often prioritize behavioral influence over informational exchange, functioning as emotional or manipulative signals tied to survival needs, such as mating calls or dominance displays, without the flexibility for discussing past events or counterfactuals inherent in human language.[110] [111] While some animals exhibit deception or cultural variants (e.g., bird songs), these lack the ostensive-inferential structure of human communication, relying instead on simple associative learning.[112] Human uniqueness stems from recursive embedding and hierarchical syntax, enabling complex causal reasoning and collective knowledge accumulation, absent in even advanced non-human examples like cetacean vocalizations or corvid gestures.[113] [103]| Feature | Human Language | Non-Human Examples |
|---|---|---|
| Productivity | Infinite novel combinations from finite rules | Fixed signals; no novel syntax (e.g., bee dances)[114] |
| Displacement | References to absent/non-present | Mostly immediate context (e.g., vervet calls)[115] |
| Cultural Transmission | Learned across generations | Largely innate/genetic (e.g., bird songs)[116] |
| Duality of Patterning | Sounds → morphemes → sentences | Holophrastic units without layering[104] |
