Basic concepts

Interest in how information iscommunicated and how its carriers convey meaning has occupied, since the time of pre-Socratic philosophers, the field of inquiry calledsemiotics, the study ofsignsand sign phenomena. Signs are the irreducible elements of communication and the carriers of meaning. The American philosopher, mathematician, and physicistCharles S. Peirce is credited with having pointed out the three dimensions of signs, which are concerned with, respectively, the body or medium of the sign, the object that the sign designates, and the interpretant or interpretation of the sign. Peirce recognized that the fundamental relations of information are essentially triadic; in contrast, all relations of the physical sciences are reducible to dyadic (binary) relations. Another American philosopher,Charles W. Morris, designated these three sign dimensions syntactic, semantic, andpragmatic, the names by which they are known today.

Information processes are executed by information processors. For a given information processor, whether physical or biological, atoken is an object, devoid of meaning, that the processor recognizes as being totally different from other tokens. A group of such unique tokens recognized by a processorconstitutes its basic “alphabet”; for example, the dot, dash, and space constitute the basic token alphabet of a Morse-code processor. Objects that carry meaning are represented by patterns of tokens calledsymbols. The latter combine to form symbolic expressions that constitute inputs to or outputs from information processes and are stored in the processor memory.

Information processors are components of an information system, which is a class of constructs. An abstract model of an information system features four basic elements: processor, memory, receptor, and effector (Figure 1). The processor has several functions: (1) to carry out elementary information processes on symbolic expressions, (2) to store temporarily in the processor’sshort-term memory the input and output expressions on which these processes operate and that they generate, (3) to schedule execution of these processes, and (4) to change this sequence of operations in accordance with the contents of the short-term memory. Thememory stores symbolic expressions, including those that representcomposite information processes, called programs. The two other components, thereceptor and theeffector, are input and output mechanisms whose functions are, respectively, to receive symbolic expressions or stimuli from the external environment for manipulation by the processor and to emit the processed structures back to the environment.

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Thepower of this abstract model of an information-processing system is provided by the ability of its component processors to carry out a small number of elementary information processes: reading; comparing; creating, modifying, and naming; copying; storing; and writing. The model, which is representative of a broad variety of such systems, has been found useful to explicate man-made information systemsimplemented on sequential information processors.

Because it has been recognized that in nature information processes are not strictly sequential, increasing attention has been focused since 1980 on the study of the human brain as an information processor of the parallel type. Thecognitive sciences, the interdisciplinary field that focuses on the study of the human mind, have contributed to the development ofneurocomputers, a new class of parallel, distributed-information processors that mimic the functioning of the humanbrain, including its capabilities for self-organization and learning. So-calledneural networks, which are mathematical models inspired by the neural circuit network of the human brain, are increasingly finding applications in areas such aspattern recognition, control of industrial processes, and finance, as well as in many research disciplines.

Information as a resource andcommodity

In the late 20th century, information acquired two major utilitarianconnotations. On the one hand, it is considered an economic resource, somewhat on par with other resources such as labour, material, and capital. This view stems from evidence that the possession, manipulation, and use of information can increase the cost-effectiveness of many physical andcognitive processes. The rise in information-processing activities in industrialmanufacturing as well as in humanproblem solving has been remarkable. Analysis of one of the three traditional divisions of the economy, theservice sector, shows a sharp increase in information-intensive activities since the beginning of the 20th century. By 1975 these activities accounted for half of thelabour force of theUnited States.

As an individual and societal resource, information has some interesting characteristics that separate it from the traditional notions of economic resources. Unlike other resources, information is expansive, with limits apparently imposed only by time and human cognitive capabilities. Its expansiveness is attributable to the following: (1) it is naturally diffusive, (2) it reproduces rather than being consumed through use, and (3) it can be shared only, not exchanged in transactions. At the same time, information is compressible, both syntactically and semantically. Coupled with its ability to be substituted for other economic resources, its transportability at very high speeds, and its ability to impart advantages to the holder of information, these characteristics are at the base of such societal industries as research, education, publishing, marketing, and even politics. Societal concern with the husbanding of information resources has extended from the traditional domain of libraries andarchives toencompass organizational, institutional, and governmental information under the umbrella of information resource management.

The second perception of information is that it is an economic commodity, which helps to stimulate the worldwide growth of a new segment of national economies—the information service sector. Taking advantage of the properties of information andbuilding on the perception of its individual and societalutility and value, this sector provides a broad range of information products and services. By 1992 the market share of the U.S. information service sector had grown to about $25 billion. This was equivalent to about one-seventh of the country’s computer market, which, in turn, represented roughly 40 percent of the global market in computers in that year. However, the probable convergence of computers and television (whichconstitutes a market share 100 times larger than computers) and its impact on information services, entertainment, and education are likely to restructure the respective market shares of the informationindustry.