Umberto Eco’s A Theory of Semiotics (1976) is a critique of the theory that the meaning of signals or signs is determined by the objects (i.e. things or events) to which they refer, and is a rejection of the notion that ‘iconic’ signs must be likenesses of their objects. Eco argues that the meaning of signals or signs is not necessarily determined by whether they refer to actual objects, and he explains that the existence of objects to which signals or signs may correspond is not a necessary condition for their signification. Eco also criticizes the notion that a typology of signs may clarify the nature of sign function, arguing instead that any typology of signs may fail to explain how different kinds of signs may share the same modes of production. Eco thus argues that the correct approach to developing a unified semiotic theory should not be to propose a typology of signs but should be to provide a method of investigating how sign-vehicles may function as signs and to provide a means of understanding how sign-vehicles may be produced and interpreted.

According to Eco, a general semiotic theory should include not only a theory of how codes may establish rules for systems of signification but a theory of how signs may be produced and interpreted. A theory of codes may clarify aspects of ‘signification,’ while a theory of sign-production may clarify aspects of ‘communication.’¹ Eco defines ‘signification’ as the semiotic event whereby a sign ‘stands for’ something, and he defines ‘communication’ as the transmission of information from a source to a destination. Communication is made possible by the existence of a code, or by a system of signification. Without a code or a system of signification, there is no set of rules to determine how the expression of signs is to be correlated with their content. The use of a code or a system of signification in order to correlate the expression and content of signs may be necessary in order to establish any form of communication.

Eco explains that a theory of sign-production should include not only a theory of communication but a theory of ‘mentions’ (i.e. referring acts) and a theory of communicational acts. A theory of communication may explain how information may be transmitted from a source (or content-continuum) through a channel (or expression-continuum) to a destination. A theory of ‘mentions’ may explain how signs may be used for naming things and for making statements about actual situations. A theory of communicational acts may explain how a sender may transmit verbal or non-verbal messages to an addressee.

Eco notes that Hjelmslev (1943) describes semiotics as a study of signs which is itself analogous to a language and which may therefore be studied by a ‘metasemiotic.’ A ‘metasemiotic’ is a metalanguage which is concerned with the terminology of semiotics. Hjelmslev also makes a distinction between scientific and non-scientific semiotics, and defines ‘semiology’ as the study of non-scientific semiotics. A ‘metasemiology’ is therefore a scientific ‘metasemiotic’ which studies the terminology of ‘semiology.’²

Eco explains that semiotics may involve many different areas of research, such as: zoosemiotics (including the study of animal communication), paralinguistics (including the study of how voice control or vocal qualities may contribute to communication), kinesics and proxemics (including the study of how physical gestures or postures may contribute to communication), tactile communication (including the study of how behavior such as a pat on the back or a slap on the shoulder may function as a mode of communication), visual communication (including the study of how photographs, drawings, maps, or diagrams may function as modes of communication), medical semiotics (including the study of medical signs and symptoms), text theory (including the study of literary texts), and the study of rhetoric, the study of ancient alphabets and secret codes, the study of formalized languages (including the study of mathematical, logical, or scientific languages), the study of natural languages (including biological and environmental signs), the study of olfactory signs, the study of codes of taste, the study of musical codes, the study of systems of objects (including the study of architecture and of industrial design), the study of cultural codes (including the study of group and family behavior), and the study of mass communication (including the study of media such as television, newspapers, magazines, and film).³

Eco defines a sign as anything which may be interpreted to ‘stand for’ (or substitute for) something. He also accepts Hjelmslev’s definition of a sign as an entity which has both an ‘expression-form’ and a ‘content-form’ and which is established by the interdependence between them. A sign is a unit consisting of an expression and a content which are connected with each other by a mutual correlation or ‘sign function.’⁴

According to Hjelmslev (1943), a ‘sign function’ is the interdependence between the expression and content of a sign. A sign cannot have a content without being an expression and cannot be an expression without having a content. The expression of a sign presupposes its content, and the content of a sign presupposes its expression.⁵ Expression and content are the two ‘functives’ (or terminals) of every ‘sign-function.’

Hjelmslev explains that the meaning of a sign should to be distinguished from the content of the sign, because a sign may in some cases be lacking in content without being lacking in meaning, and may in other cases be lacking in meaning despite not being lacking in content.⁶

Eco defines a ‘signal’ as a unit of information which may be transmitted from a source to a destination, and argues that a ‘signal’ may not necessarily be a communicational act. A ‘signal’ may be a stimulus to a particular response, but may not necessarily be intended to mean anything. Thus, a ‘signal’ may not necessarily be a sign, and may not necessarily have any signification.

Eco also explains that a ‘code’ is a rule which correlates elements of an expression-plane with elements of a content-plane. A ‘code’ is an instrument for connecting the expression of signs to their content, and is a correlational device which generates ‘sign-functions.’ A ‘code’ is also a rule for sign production and interpretation, in that it determines how the expression and content of signs are to be correlated.

Eco argues that any given sign must be an element of an expression-plane, and must therefore be conventionally correlated to one or more elements of a content-plane.⁷ A sign cannot belong to an expression-plane without belonging to a content-plane, and cannot belong to a content-plane without belonging to an expression-plane. However, a sign may in some cases belong to more than one expression-plane, and may in some cases belong to more than one content-plane. The expression of a sign may have more than one content, and the content of a sign may have more than one expression.

Eco explains that a system of signification may include not only syntactic rules (i.e. rules for the combination of signs) but semantic rules (i.e. rules for the signification of signs) and behavioral rules (i.e. rules for the coordination of syntactic and semantic rules, so that proper understanding of a given array of signs may produce a corresponding behavioral response). Thus, an ‘s-code’ (or code as system) is a system of rules which has syntactic, semantic, and behavioral applications. An ‘s-code’ differs from an ordinary ‘code,’ in that an ‘s-code’ is a system of signification, while a ‘code’ is merely a correlational device for producing or interpreting signs. A ‘code’ may correlate the items of different information systems or the items of different ‘s-codes.’

Eco argues that the ‘referential fallacy’ in classical theories of semiotics is the false assumption that the meaning of a sign-vehicle is determined by its referent (i.e. by the object to which the sign-vehicle refers). The ‘extensional fallacy’ in classical theories of semiotics is the false assumption that the meaning of a sign-vehicle is determined by its extension (i.e. by the class of objects to which the sign-vehicle refers). According to Eco, both the ‘referential fallacy’ and the ‘extensional fallacy’ may distort a theory of codes by promoting the false assumption that the object of a sign, or the class of objects to which the sign refers, is a necessary condition for the sign’s meaning or signification.

Eco also argues that the content and not the referent of a sign is the location of the sign’s meaning. The meaning of a sign is a ‘cultural unit,’ in that the meaning of every sign is culturally defined. A ‘cultural unit’ may be defined as a semantic unit (i.e. a content unit or ‘sememe’), in that it may be analyzed into its elementary semantic components (i.e. its ‘semes’ or semantic markers). A ‘cultural unit’ may also be defined as a syntactic unit (i.e. an expression unit or ‘lexeme’), in that it may be analyzed into its elementary syntactic components (i.e. its syntactic markers).⁸

According to Eco, semantic units may be either ‘categorematic’ (i.e. having an independent meaning, and being capable of standing on their own as terms in a categorical proposition) or ‘syncategorematic’ (i.e. having no independent meaning, and being incapable of standing on their own as terms in a categorical proposition). ‘Syncategorematic’ units must be joined to ‘categorematic’ units in order to function as terms in a categorical proposition.

Eco also explains that every semantic unit may be an element of a semantic field. Insofar as semantic units are ‘cultural units,’ the semantic field to which a given semantic unit belongs may be an aspect of the world-vision belonging to a particular culture.⁹ The semantic fields of a culture or society may be either complementary, contradictory, or indifferent to each other.

Eco argues that every ‘cultural unit’ is an element of a system of other ‘cultural units’ which may limit or further define its meaning. Every ‘cultural unit’ may be an element of more than one semantic field. ‘Cultural units’ may also in some cases be ambiguous or equivocal in nature, and may in some cases be ‘fuzzy concepts.’ ‘Fuzzy concepts’ may be ‘sememes’ which are open to different ‘readings’ because of the different meanings which they may have in different situations or because of the different ways in which they may be combined with other ‘cultural units.’¹⁰

Eco explains that the semantic markers of any given ‘sememe’ may be either denotative or connotative. Denotative markers do not rely on a preceding denotation in order to constitute a 'sememe,' but connotative markers rely on a preceding denotation in order to constitute a 'sememe.' Denotative markers form the content of an expression, but connotative markers form the content of a ‘sign-function.’¹¹

Eco also explains that a ‘sign-function’ may be denotative to the extent that its expression does not signify the content of another ‘sign-function,’ but may be connotative to the extent that its expression signifies the content of another ‘sign-function.’ To denote is to signify something without relying on a preceding denotation, but to connote is to rely on a preceding denotation in order to signify something.

Eco distinguishes between ‘types’ and ‘tokens’ as signs which may have different modes of production. ‘Types’ may be replicated by ‘tokens,’ and ‘tokens’ may be motivated by ‘types.’ According to Peirce (1897), a ‘type’ is a law which is a sign (i.e.a ‘legisign’), and a ‘token’ is an actually existing thing or event which is a sign. A ‘type’ is a general rule which acts through a ‘replica’ (i.e. a sign which is an individual example of its application), and a ‘token’ may also be a ‘replica.’ According to Eco, a ‘type’ is an abstract model for a concrete ‘token,’ and a ‘token’ is an actual sign-vehicle which is used for communication. A ‘token’ is also an individual occurrence of an expression, and may signify either an ‘expression-type’ or a ‘content-type.’ An ‘expression-type’ is an element of an expression-plane, while a ‘content-type’ is an element of a content-plane.

Eco argues that modes of sign-production may be described by a typology according to four criteria: 1) the amount of physical labor which is necessary in order to produce expressions, 2) the type-token ratio, 3) the continuum which is to be shaped, and 4) the mode and rate of articulation. These four criteria may be used to describe both the modes of sign-production by which expressions are produced and the modes of sign-production by which ‘expression-tokens’ are correlated with ‘expression-types’ or‘content’-types.’

Eco explains that modes of sign-production which may be defined by the intensity of the physical labor which they require for the production of sign-expressions include: 1) recognition, 2) ostension, 3) replication, and 4) invention. Recognition involves a reconstitution of a previous experience of sign-expressions. Ostension involves a choice of existing or potentially existing sign-expressions as ‘tokens’ of ‘expression-types.’ Replication involves producing ‘expression-tokens’ according to the model of already-existing ‘expression-types.’ Invention involves the production of completely new sign-expressions.

Eco also explains that type/token ratios may be of two kinds: 1) ‘ratio facilis,’ and 2) ‘ratio difficilis.’ ‘Ratio facilis’ is a mode of sign-production in which an ‘expression-type’ is replicated by an ‘expression token.’ ‘Ratio difficilis’ is a mode of sign-production in which a ‘content-type’ is correlated with an ‘expression-token.’

According to Eco, the replication of ‘types’ by ‘tokens’ may occur by means of ‘vectors,’ ‘stylizations,’ ‘combinational units,’ and ‘pseudo-combinational units.’ ‘Vectors’ are markers of a system of expressions which must be combined with markers of another system of expressions in order to produce an expression. ‘Stylizations’ are expression-markers which are correlated to content-markers by extra-coding, such as overcoding. ‘Combinational units’ are combinations of expression-markers which may be correlated with combinations of content-markers. ‘Pseudo-combinational units’ are expression-markers which are not correlated with content-markers (and which therefore have no meaning), but which are nevertheless governed by combinational rules.

Eco explains that the replication of ‘types’ by means of ‘vectors’ is a ‘ratio difficilis’ mode of sign-production. The replication of ‘types’ by means of ‘stylizations’ is a combined ‘ratio difficilis’ and ‘ratio facilis’ mode of sign-production. The replication of ‘types’ by means of ‘combinational’ or ‘pseudo-combinational’ units is a ‘ratio facilis’ mode of sign-production.

Eco’s theory of codes and theory of modes of sign production provide many insights into the ways in which the meaning of signs may be culturally defined. He rejects what he calls ‘naïve iconism’ as a theory which falsely assumes that so-called 'iconic' signs must be similar or analgous to their objects, and he argues instead that the iconicity of any particular mode of sign-production is a matter of cultural convention. He explains, however, that to say that the iconicity of any particular mode of sign-production is a matter of cultural convention is not to say that it is a matter which is decided upon arbitrarily. To the contrary, the degree of iconicity of any particular expression may be determined by the degree to which the expression is correlated with its content, and may not be determined by the degree to which the expression is similar or analogous to some object to which it may refer. Iconicity may therefore be a property of a particular mode of producing ‘sign-functions,’ but may not be a property of any particular kind of sign.

¹Umberto Eco, A Theory of Semiotics (Bloomington: Indiana University Press, 1976), p.4.
²Louis Hjelmslev, Prolegomena to a Theory of Language (Madison: University of Wisconsin Press, 1963), p. 120.
³Eco, A Theory of Semiotics, pp. 9-13.
⁴Hjelmslev, Prolegomena to a Theory of Language, p. 58.
⁵Ibid., p. 49.
⁶Ibid., p. 49.
⁷Eco, A Theory of Semiotics, p. 48.
⁸Ibid., p. 72.
⁹Ibid., p. 76.
¹⁰Ibid., p. 82.
¹¹Ibid., p. 86.

Eco, Umberto. A Theory of Semiotics. Bloomington: Indiana University Press, 1976.

Hjelmslev, Louis. Prolegomena to a Theory of Language. Madison: University of Wisconsin Press, 1963.

Peirce, Charles Sanders. Collected Papers of Charles Sanders Peirce. Volumes V and VI. Cambridge: Harvard University Press, 1960.