According to the relationship between the sign and the referent, signs are distinguished as indexical, iconic, and symbolic. This distinction was introduced by Peirce.
According to the definition that Peirce gave:
“The icon has no direct dynamic connection with the object it represents; it only happens that its qualities resemble those of the object and thereby evoke similar feelings in the mind that perceives the resemblance. But in reality, it is not connected with them.
The index is physically connected with its object; they form an organic pair, but the interpreting mind has nothing to do with this connection other than to recognize it after it has been established.
The symbol is connected with its object due to the idea in the mind of the person using the symbol, without which such a relation would not exist”
3.3.1. Index
Index or indexical sign derives from the Latin index meaning indicator.
The indexical sign is in an immediate direct relationship with its referent without any similarity between them.
Peirce claims that:
“An index is a sign, or a representation, that refers to its object not so much by resemblance or analogy to it, nor because it is associated with the general traits that the object possesses, but because it is in a dynamic (especially spatial) relation with the individual object, on one hand, and, on the other hand, with the meaning or memory of a person for whom it serves as a sign […]
Indexes can be distinguished from other signs by three characteristic features:
- first, they do not have a significant resemblance to their objects;
- second, they refer to individualities, single elements, single sets of elements, or single continua;
- third, they direct attention to their object by blind force.
But it would be difficult, if not impossible, to find a completely pure index or to find a sign absolutely devoid of indexical quality. Psychologically, the action of indexes depends on association by contiguity rather than association by resemblance or intellectual operations”
According to Prieto, an index is “an immediately sensed fact that acquaints us with something in relation to another fact, which it is not itself.”
For Umberto Eco, an index is “a sign related to the object it signifies by virtue of a real impact from that object”.
The relationship between the index and its object is direct—the object directly produces its index (fire produces smoke, a car produces tire tracks, perfume produces a scent, illness produces a fever, etc.), but the object itself remains hidden from the senses.
Smoke is a sign of fire only if the fire itself is not visible. The sight of a fire producing smoke is not a sign for anyone.
Understanding indexes is an important factor in an individual’s orientation in their environment, and its correct interpretation depends on their cultural experience. For instance, a person can recognize rashes as an index of an allergy only if they already know that allergies cause rashes.
Indexes can be interpreted as:
- Anticipatory – when observed before reaching their source, for example, the smell of delicious food before reaching the kitchen.
- Simultaneous – when they appear simultaneously with their object, such as the symptoms of a disease.
- Lagging – when their effect continues after the action of their object, for example, tire tracks left by a car.
Regardless of whether the index is anticipatory or lagging, it must exist together with its object for at least a fraction of a second, at the moment of its creation.
3.3.2. Icon
Icon or iconic sign is derived from the Greek ‘eikon’ meaning “image.”
The iconic sign has no direct relationship with its referent, but it is related to it by resemblance.
According to Peirce,
“a sign can be iconic, that is, represent its object mainly by resemblance, whatever its mode of existence”
The iconic sign is more or less a copy of its referent. But, as is well known, even the best copy differs from the original.
The peculiarity of iconic signs is that, as copies of the object, they represent it more or less limitedly and incompletely. For example, a photograph of Umberto Eco is only a two-dimensional visual representation, which does not correspond to his “volume” or intellectual qualities.
The iconic sign does not indicate; it shows—not the most essential characteristic of the object, but the most recognizable one. Iconic signs can also be simultaneous, lagging, or anticipatory (technical and architectural projects, models, and schemes are anticipatory reduced models).
3.3.3. Symbol
Symbol or symbolic sign is a term that comes from Greek symbolon meaning “to throw together.”
The symbolic sign has neither a direct connection nor a resemblance to its referent. The relationship between them is conventional, established by social convention within the community that uses the respective sign system.
Initially, the word symbol referred to an object broken into two parts, whose halves, when joined, served as a means of recognition for the bearers and proved the previously agreed commitments of hospitality and mutual assistance.
By extending this meaning, the word “symbol” came to mean any objects used for identification—amulets, marked personal belongings, etc.
Historically, symbolic signs are associated with phenomena that have no iconic correspondence—qualities, states, or actions (the dove is a symbol of peace, the lion is a symbol of power and strength, and it is no coincidence that it is one of the most widespread signs in heraldry).
Peirce defines a symbol as “a sign that refers to its object by virtue of a law, habit, or association of general ideas, which acts in such a way that it causes the symbol to be interpreted as referring to that object” .
This category includes mathematical symbols (+, -, x, =), logical symbols (¬, ∧, ∨), astrological symbols (♈, ♉, ♊), playing card symbols (♠, ♥, ♦, ♣), linguistic signs (words), and others.
These types of signs are interpreted solely according to the social convention of the community that uses them.
3.3.4. Terminological and Conceptual Differences Among Various Schools and Authors
Serious contradictions arise from the differences in the concepts of Peirce and Saussure and, accordingly, their followers.
Thus, two different classifications are formed: on the one hand, the Francophone schools, and on the other hand, all the rest.
Followers of Peirce adhere to the simplified form of his classification:
- Sign: Icon, Symbol, Index
Francophone semiotic schools follow, on the one hand, Prieto, who distinguishes between natural and artificial signs—signals, and on the other hand, Saussure distinguishes between sign and symbol.
3.3.4.1. Signal
Some authors use the term “signal” as a synonym for “sign.”
French semioticians use it as a synonym for “artificially created signs,” under the influence of Prieto. In the French language, the word “signal” means a deliberate sign.
However, this is not the case in other languages, where the term “signal” is a loanword and does not have the same meaning.
Therefore, to avoid confusion, it seems appropriate to adopt Eco’s proposal to differentiate the term signal from sign and to use it only in relation to the transmission of information in technical systems, where there is no transmission of meaning.
Eco argues as follows:
A signal is a relevant unit of some system, corresponding to a given content, but it can also be a material system without any semiotic purpose. As such, it is studied by information theory in the strict sense of the word. The signal can be a stimulus that carries no meaning but causes or provokes something: however, when used as a recognized phenomenon preceding some anticipated consequence, it can be considered a sign insofar as it signifies that consequence (in relation to the sender).
This concept aligns with the views of Cassirer, who differentiates between a symbol—part of the human world of meaning—and a signal—part of the physical world of existence.
3.3.4.2. Symbol
The second and much more serious contentious point in classifications is the term “symbol.” For the disputes and difficulties in defining the concept of symbol.
3.3.4.2.1. The Symbol as a Sign
Many authors use symbol and sign as synonyms (Levi-Strauss, Lacan, etc.). Others attempt to differentiate between the two terms.
Losev introduces an “axiom” for the symbol:
Every sign can have an infinite number of meanings, i.e., be a symbol.
The logic of these reflections, which define the sign as an “embryo” and something insignificant, seems, at the very least, discriminatory. In this sense, the proposed “axiom” is a statement unacceptable to contemporary semiotic theory.
3.3.4.2.2. The Symbol as an Iconic Sign
Kant and Hegel define the symbol as a meaningful fact that represents a concept by analogy, i.e., as an iconic sign.
This definition is supported by French semioticians who refer to Saussure. According to him,
it is characteristic of the symbol that it is never wholly arbitrary; it is not empty—it retains a trace of the natural connection between the signifier and the signified.
The symbol of justice, the scales, could not be replaced by just anything, such as a chariot.
According to French semioticians, the symbol is a fully or partially motivated sign that maintains an analogous relationship with its referent.
In Anglo-Saxon classifications, on the other hand, this definition corresponds to iconic signs, which range from the closest possible models to the referent to the most distant, as long as there is the slightest resemblance.
The term “iconic sign” was introduced into French semiotics only in 1973 by Jean Martinet, but not all French researchers followed this proposal. More recent studies, which recognize the existence of iconic signs, still perceive them as signs with a high degree of similarity.
3.3.4.2.3. The Symbol as a Conventional Sign
Anglo-Saxon semioticians follow Peirce’s classification and for them, the symbolic sign is entirely conventional, with no observed connection between the sign and its referent, and it is interpreted only by prior established convention.
Many authors point to the etymology of the word to make its meaning more understandable.
Peirce also resorts to etymological arguments:
The word ‘symbol’ has so many meanings that it would be an insult to language to add a new one. I do not think that the meaning I attribute to it—that of a conventional or habit-dependent sign (acquired or innate)—is a new meaning; it is more of a return to its original meaning. Etymologically, it would mean something thrown together hastily, just as embolon is something wedged into something else, klinobolon is something placed aside, and probolon is something placed below, a prenup gift… But the Greeks often used ‘to throw, to gather together’ (symballein) to express the establishment of an agreement, a convention. Or, we find the symbol (symbolon) used early and often to mean convention or agreement. Aristotle called the name a ‘symbol,’ that is, a conventional sign.
Let us recall that for French semioticians, the symbol is not conventional but analogous. As a result of this contradiction between the two schools, the same sign can fall into different categories.
3.3.4.3. On the Term “Sign in the Narrow Sense”
Retaining Saussure‘s term, the French school calls a sign what other semioticians call a symbol.
That is, a sign in the narrow sense is a sign whose relationship with the referent is entirely conventional and unmotivated.
Some semioticians, following Saussure‘s example, even acknowledge a special status for linguistic signs in this category, dividing it into “linguistic” and “non-linguistic signs.” This view is appropriate for semiolinguistics, but not for general semiotics, which generalizes classes of signs without concerning itself with the specifics of the particular sign system to which they belong.
3.3.4.4. Summary:
The differences between the French school of thought and the others are so misleading (considering that the same terminological word conceals different concepts) that semioticians around the world appreciate the use of the French term semiology.
As Robert Scholes expresses it:
The fact that French semioticians use the term semiology is a ‘useful tool to distinguish their research from other work in the field of international semiotics, which now dominates in Eastern Europe, Italy, and the USA’.
The controversial points in traditional French classifications are as follows:
- The use of the term signal for artificial signs. First, there is no rule prohibiting natural signs from being called signals (clouds are a signal of rain). Second, the term signal duplicates the term sign, and it is appropriate to reserve it for technical systems, as Eco suggests.
- Regarding the term symbol, there is no definition postulating that “it is never wholly arbitrary” and that it requires the presence of a “natural connection between the signifier and the signified.” The symbol of justice, the scales, indeed cannot be replaced by a chariot in American and European culture, but the word “sun” also cannot be replaced by the word “elephant,” and the reason for this is not some natural connection between the sign and its referent, but the power of established social convention (the language system is considered a conventional semiotic system par excellence). If the ancient Greeks had depicted Themis not with scales, but with another measuring instrument, we might have a land surveyor’s ruler today as a symbol of justice. The question of how and by what logic this social convention is established and whether it is entirely arbitrary is a matter for the cognitive sciences.
- The concept of a sign in the narrow sense only confuses the classification rather than simplifying it. In connection with what was said in point 2, there is no reason to replace the term symbol with sign. Comparative analysis shows that Peirce’s classification is more consistent. It is no coincidence that this classification is the most widespread and most commonly used in contemporary semiotics. The new generation of French semioticians also increasingly uses this classification.
We should always keep in mind Peirce’s claim that there are no “pure” types of signs and that the three semiotic processes can be found in the same sign.
Categorizing a sign as an index, icon, or symbol only indicates the dominant indexical, iconic, or symbolic sign process within it.
Hoofprints are indexical signs, but they iconically repeat the shape of the hoof. The iconic sign of the compass is supported by social convention as a symbolic sign. The iconic signs of photography are formed through the indexical imprinting of light on the photographic plate. The graphic symbols in writing, which are considered symbols par excellence, are iconically formed.
