+ 2.1 I. Qualisign, sinsign, legisign
+ 2.2 II. Icon, index, symbol
+ 2.3 III. Rheme, dicisign, argument


Peirce proposes several typologies and definitions of the signs. More than 76 definitions of what a sign is have been collected throughout Peirce's work.^[21] Some canonical typologies can nonetheless be observed, one crucial one being the distinction between "icons", "indices" and "symbols" (CP 2.228, CP 2.229 and CP 5.473). The icon-index-symbol typology is chronologically the first but structurally the second of three that fit together as a trio of three-valued parameters in regular scheme of nine kinds of sign. (The three "parameters" (not Peirce's term) are not independent of one another, and the result is a system of ten classes of sign, which are shown further down in this article.)


Peirce proposes several typologies and definitions of the signs. More than 76 definitions of what a sign is have been collected throughout Peirce's work.^[21] Some canonical typologies can nonetheless be observed, one crucial one being the distinction between "icons", "indices" and "symbols" (CP 2.228, CP 2.229 and CP 5.473). The icon-index-symbol typology is chronologically the first but structurally the second of three that fit together as a trio of three-valued parameters in regular scheme of nine kinds of sign. (The three "parameters" (not Peirce's term) are not independent of one another, and the result is a system of ten classes of sign, which are shown further down in this article.)


1. Qualisigns, sinsigns, and legisigns . Every sign is either (qualisign) a quality or possibility, or (sinsign) an actual individual thing, fact, event, state, etc., or (legisign) a norm, habit, rule, law. (Also called types, tokens, and tones, also potisigns, actisigns, and famisigns.)
2. Icons, indices, and symbols. Every sign refers either (icon) through similarity to its object, or (index) through factual connection to its object, or (symbol) through interpretive habit or norm of reference to its object.


2. Icons, indices, and symbols. Every sign refers either (icon) through similarity to its object, or (index) through factual connection to its object, or (symbol) through interpretive habit or norm of reference to its object.
3. Rhemes, dicisigns, and arguments . Every sign is interpreted either as (rheme) term-like, standing for its object in respect of quality, or as (dicisign) proposition-like, standing for its object in respect of fact, or as (argument) argumentative, standing for its object in respect of habit or law. This is the trichotomy of all signs as building blocks of inference. (Also called sumisigns, dicisigns, and suadisigns, also semes, phemes, and delomes.)


In later years, Peirce attempted a finer level of analysis, defining sign classes in terms of relations not just to sign, object, and interpretant, but to sign, immediate object, dynamic object, immediate interpretant, dynamic interpretant, and final or normal interpretant. He aimed at 10 trichotomies of signs, with the above three trichotomies interspersed among them, and issuing in 66 classes of signs. He did not bring that system into a finished form. In any case, in that system, icon, index, and symbol were classed by category of how they stood for the dynamic object, while rheme, dicisign, and argument were classed by the category of how they stood for the dynamic object to the final or normal interpretant.^[24]


These conceptions are specific to Peirce's theory of signs and are not exactly equivalent to general uses of the notions of "icon", "symbol", "index", "tone", "token", "type", "term", "proposition", "argument," and "rhema".


[edit] II. Icon, index, symbol


This is the typology of the sign as distinguished by phenomenological category of its way of denoting the object (set forth in 1867 and many times in later years). This typology emphasizes the different ways in which the sign refers to its object — the icon by a quality of its own, the index by real connection to its object, and the symbol by a habit or rule for its interpretant. The modes may be compounded, for instance, in a sign that displays a forking line iconically for a fork in the road and stands indicatively near a fork in the road.
1. An icon (also called likeness and semblance) is a sign that denotes its object by virtue of a quality which is shared by them but which the icon has irrespectively of the object. The icon (for instance, a portrait or a diagram) resembles or imitates its object. The icon has, of itself, a certain character or aspect, one which the object also has (or is supposed to have) and which lets the icon be interpreted as a sign even if the object does not exist. The icon signifies essentially on the basis of its "ground." (Peirce defined the ground as the pure abstraction of a quality, and the sign's ground as the pure abstraction of the quality in respect of which the sign refers to its object, whether by resemblance or, as a symbol, by imputing the quality to the object.^[26]). Peirce called an icon apart from a label, legend, or other index attached to it, a "hypoicon", and divided the hypoicon into three classes: (a) the image, which depends on a simple quality; (b) the diagram,


This is the typology of the sign as distinguished by phenomenological category of its way of denoting the object (set forth in 1867 and many times in later years). This typology emphasizes the different ways in which the sign refers to its object — the icon by a quality of its own, the index by real connection to its object, and the symbol by a habit or rule for its interpretant. The modes may be compounded, for instance, in a sign that displays a forking line iconically for a fork in the road and stands indicatively near a fork in the road.
1. An icon (also called likeness and semblance) is a sign that denotes its object by virtue of a quality which is shared by them but which the icon has irrespectively of the object. The icon (for instance, a portrait or a diagram) resembles or imitates its object. The icon has, of itself, a certain character or aspect, one which the object also has (or is supposed to have) and which lets the icon be interpreted as a sign even if the object does not exist. The icon signifies essentially on the basis of its "ground." (Peirce defined the ground as the pure abstraction of a quality, and the sign's ground as the pure abstraction of the quality in respect of which the sign refers to its object, whether by resemblance or, as a symbol, by imputing the quality to the object.^[26]). Peirce called an icon apart from a label, legend, or other index attached to it, a "hypoicon", and divided the hypoicon into three classes: (a) the image, which depends on a simple quality; (b) the diagram,


1. An icon (also called likeness and semblance) is a sign that denotes its object by virtue of a quality which is shared by them but which the icon has irrespectively of the object. The icon (for instance, a portrait or a diagram) resembles or imitates its object. The icon has, of itself, a certain character or aspect, one which the object also has (or is supposed to have) and which lets the icon be interpreted as a sign even if the object does not exist. The icon signifies essentially on the basis of its "ground." (Peirce defined the ground as the pure abstraction of a quality, and the sign's ground as the pure abstraction of the quality in respect of which the sign refers to its object, whether by resemblance or, as a symbol, by imputing the quality to the object.^[26]). Peirce called an icon apart from a label, legend, or other index attached to it, a "hypoicon", and divided the hypoicon into three classes: (a) the image, which depends on a simple quality; (b) the diagram,


1. An icon (also called likeness and semblance) is a sign that denotes its object by virtue of a quality which is shared by them but which the icon has irrespectively of the object. The icon (for instance, a portrait or a diagram) resembles or imitates its object. The icon has, of itself, a certain character or aspect, one which the object also has (or is supposed to have) and which lets the icon be interpreted as a sign even if the object does not exist. The icon signifies essentially on the basis of its "ground." (Peirce defined the ground as the pure abstraction of a quality, and the sign's ground as the pure abstraction of the quality in respect of which the sign refers to its object, whether by resemblance or, as a symbol, by imputing the quality to the object.^[26]). Peirce called an icon apart from a label, legend, or other index attached to it, a "hypoicon", and divided the hypoicon into three classes: (a) the image, which depends on a simple quality; (b) the diagram,


1. An icon (also called likeness and semblance) is a sign that denotes its object by virtue of a quality which is shared by them but which the icon has irrespectively of the object. The icon (for instance, a portrait or a diagram) resembles or imitates its object. The icon has, of itself, a certain character or aspect, one which the object also has (or is supposed to have) and which lets the icon be interpreted as a sign even if the object does not exist. The icon signifies essentially on the basis of its "ground." (Peirce defined the ground as the pure abstraction of a quality, and the sign's ground as the pure abstraction of the quality in respect of which the sign refers to its object, whether by resemblance or, as a symbol, by imputing the quality to the object.^[26]). Peirce called an icon apart from a label, legend, or other index attached to it, a "hypoicon", and divided the hypoicon into three classes: (a) the image, which depends on a simple quality; (b) the diagram,


1. An icon (also called likeness and semblance) is a sign that denotes its object by virtue of a quality which is shared by them but which the icon has irrespectively of the object. The icon (for instance, a portrait or a diagram) resembles or imitates its object. The icon has, of itself, a certain character or aspect, one which the object also has (or is supposed to have) and which lets the icon be interpreted as a sign even if the object does not exist. The icon signifies essentially on the basis of its "ground." (Peirce defined the ground as the pure abstraction of a quality, and the sign's ground as the pure abstraction of the quality in respect of which the sign refers to its object, whether by resemblance or, as a symbol, by imputing the quality to the object.^[26]). Peirce called an icon apart from a label, legend, or other index attached to it, a "hypoicon", and divided the hypoicon into three classes: (a) the image, which depends on a simple quality; (b) the diagram,


1. An icon (also called likeness and semblance) is a sign that denotes its object by virtue of a quality which is shared by them but which the icon has irrespectively of the object. The icon (for instance, a portrait or a diagram) resembles or imitates its object. The icon has, of itself, a certain character or aspect, one which the object also has (or is supposed to have) and which lets the icon be interpreted as a sign even if the object does not exist. The icon signifies essentially on the basis of its "ground." (Peirce defined the ground as the pure abstraction of a quality, and the sign's ground as the pure abstraction of the quality in respect of which the sign refers to its object, whether by resemblance or, as a symbol, by imputing the quality to the object.^[26]). Peirce called an icon apart from a label, legend, or other index attached to it, a "hypoicon", and divided the hypoicon into three classes: (a) the image, which depends on a simple quality; (b) the diagram,


1. An icon (also called likeness and semblance) is a sign that denotes its object by virtue of a quality which is shared by them but which the icon has irrespectively of the object. The icon (for instance, a portrait or a diagram) resembles or imitates its object. The icon has, of itself, a certain character or aspect, one which the object also has (or is supposed to have) and which lets the icon be interpreted as a sign even if the object does not exist. The icon signifies essentially on the basis of its "ground." (Peirce defined the ground as the pure abstraction of a quality, and the sign's ground as the pure abstraction of the quality in respect of which the sign refers to its object, whether by resemblance or, as a symbol, by imputing the quality to the object.^[26]). Peirce called an icon apart from a label, legend, or other index attached to it, a "hypoicon", and divided the hypoicon into three classes: (a) the image, which depends on a simple quality; (b) the diagram,
whose internal relations, mainly dyadic or so taken, represent by analogy the relations in something; and (c) the metaphor, which represents the representative character of a sign by representing a parallelism in something else.^[27] A diagram can be geometric, or can consist in an array of algebraic expressions, or even in the common form "All __ is ___" which is subjectable, like any diagram, to logical or mathematical transformations. Peirce held that mathematics is done by diagrammatic thinking — observation of, and experimentation on, diagrams.


whose internal relations, mainly dyadic or so taken, represent by analogy the relations in something; and (c) the metaphor, which represents the representative character of a sign by representing a parallelism in something else.^[27] A diagram can be geometric, or can consist in an array of algebraic expressions, or even in the common form "All __ is ___" which is subjectable, like any diagram, to logical or mathematical transformations. Peirce held that mathematics is done by diagrammatic thinking — observation of, and experimentation on, diagrams.
2. An index* is a sign that denotes its object by virtue of an actual connection involving them, one that he also calls a real relation in virtue of its being irrespective of interpretation. It is in any case a relation which is in fact, in contrast to the icon, which has only a ground for denotation of its object, and in contrast to the symbol, which denotes by an interpretive habit or law. An index which compels attention without conveying any information about its object is a pure index, though that may be an ideal limit never actually reached. If an indexical relation is a resistance or reaction physically or causally connecting an index to its object, then the index is a reagent (for example smoke coming from a building is a reagent index of fire). Such an index is really affected or modified by the object, and is the only kind of index which can be used in order to ascertain facts about its object. Peirce also usually held that an index does not have to be an actual
individual fact or thing, but can be a general; a disease symptom is general, its occurrence singular; and he usually considered a designation to be an index, e.g., a pronoun, a proper name, a label on a diagram, etc. (In 1903 Peirce said that only an individual is an index^[28], gave "seme" as an alternate expression for "index", and called designations "subindices or hyposemes,^[29] which were a kind of symbol; he allowed of a "degenerate index" indicating a non-individual object, as exemplified by an individual thing indicating its own characteristics. But by 1904 he returned to allowing indices to be generals and to classing designations as indices. In 1906 he changed the meaning of "seme" to that of the earlier "sumisign" and "rheme".)


* Note: in "On a New List of Categories" (1867) Peirce gave the unqualified term "sign" as an alternate expression for "index", and gave "general sign" as an alternate expression for "symbol". "Representamen" was his blanket technical term for any and every sign or signlike thing covered by his theory^[32]. Peirce soon reserved "sign" to its broadest sense, for index, icon, and symbol alike. He also eventually decided that the symbol is not the only sign which can be called a "general sign" in some sense, and that indices and icons can be generals, generalities, too. The general sign, as such, the generality as a sign, he eventually called, at various times, the "legisign" (1903, 1904), the "type" (1906, 1908), and the "famisign" (1908).


* Note: in "On a New List of Categories" (1867) Peirce gave the unqualified term "sign" as an alternate expression for "index", and gave "general sign" as an alternate expression for "symbol". "Representamen" was his blanket technical term for any and every sign or signlike thing covered by his theory^[32]. Peirce soon reserved "sign" to its broadest sense, for index, icon, and symbol alike. He also eventually decided that the symbol is not the only sign which can be called a "general sign" in some sense, and that indices and icons can be generals, generalities, too. The general sign, as such, the generality as a sign, he eventually called, at various times, the "legisign" (1903, 1904), the "type" (1906, 1908), and the "famisign" (1908).


This is the typology of the sign as distinguished by the phenomenological category which the sign's interpretant attributes to the sign's way of denoting the object (set forth in 1902, 1903, etc.):
1. A rheme (also called sumisign and seme*) is a sign that represents its object in respect of quality and so, in its signified interpretant, is represented as a qualisign (a kind of icon)^[33], though it actually may be icon, index, or symbol. The rheme* (seme) stands as its object for some purpose.^[34] A proposition with the subject places left blank is a rheme; but subject terms by themselves are also rhemes. A proposition, said Peirce, can be considered a zero-place rheme, a zero-place predicate.


1. A rheme (also called sumisign and seme*) is a sign that represents its object in respect of quality and so, in its signified interpretant, is represented as a qualisign (a kind of icon)^[33], though it actually may be icon, index, or symbol. The rheme* (seme) stands as its object for some purpose.^[34] A proposition with the subject places left blank is a rheme; but subject terms by themselves are also rhemes. A proposition, said Peirce, can be considered a zero-place rheme, a zero-place predicate.
2. A dicisign (also called dicent sign and pheme ) is a sign that represents its object in respect of actual existence and so, in its signified interpretant, is represented as indexical^[35], though it actually may be either index or symbol. The dicisign separately indicates its object (as subject of the predicate).^[36] The dicisign "is intended to have some compulsive effect on the interpreter of it".^[34] Peirce had generalized the idea of proposition to where a weathercock, photograph, etc., could be considered propositions (or "dicisigns," as he came to call them). A proposition in the conventional sense is a dicent symbol (also called symbolic dicisign). Assertions are also dicisigns.


AND Peircelines2.PNG
II. ...the sign's way of denoting its OBJECT: ICON
(Likeness, etc.) OR INDEX


*Note: As noted above, in "On a New List of Categories" (1867) Peirce gave the unqualified word "sign" as an alternate expression for "index," and gave "general sign" as an alternate expression for "symbol." Peirce soon reserved "sign" to its broadest sense, for index, icon, and symbol alike, and eventually decided that symbols are not the only signs which can be called "general signs" in some sense. See note at end of section "II. Icon, index, symbol" for details.


*Note: As noted above, in "On a New List of Categories" (1867) Peirce gave the unqualified word "sign" as an alternate expression for "index," and gave "general sign" as an alternate expression for "symbol." Peirce soon reserved "sign" to its broadest sense, for index, icon, and symbol alike, and eventually decided that symbols are not the only signs which can be called "general signs" in some sense. See note at end of section "II. Icon, index, symbol" for details.
**Note: A term in the conventional sense is not just any rheme; it is a kind of rhematic symbol. A proposition in the conventional sense is not just any dicisign, it is a kind of dicent symbol.


in parentheses Some examples
(I) Qualisign Icon Rheme (Rhematic Iconic) Qualisign A feeling of “red”
(II) Sinsign Icon Rheme (Rhematic) Iconic Sinsign An individual diagram


(I) Qualisign Icon Rheme (Rhematic Iconic) Qualisign A feeling of “red”
(II) Sinsign Icon Rheme (Rhematic) Iconic Sinsign An individual diagram
(III) Index Rheme Rhematic Indexical Sinsign A spontaneous cry


(IV) Dicisign Dicent (Indexical) Sinsign A weathercock or photograph
(V) Legisign Icon Rheme (Rhematic) Iconic Legisign A diagram, apart from its factual individuality
(VI) Index Rheme Rhematic Indexical Legisign A demonstrative pronoun


29. ^ In "A Syllabus of Certain Topics of Logic", EP 2:274, 1903, and viewable under "Subindex, Hyposeme" at the CDPT.
30. ^ MS599 c.1902 "Reason's Rules", relevant quote viewable under "MS 599" in "Role of Icons In Predication", Joseph Ransdell, ed. Arisbe Eprint.
31. ^ "A Syllabus of Certain Topics of Logic", EP 2:274, 1903, and "Logical Tracts, No. 2", CP 4.447, c. 1903. Relevant quotes viewable at the CDPT, under "Symbol".


* Arisbe: The Peirce Gateway, Joseph Ransdell, ed. 95 online works by Peirce as of 2/17/09, with annotations. 100s of online papers on Peirce. The peirce-l e-forum.
+ "Passages from Peirce, chronologically ordered: On Role of Icons in Predication".
* Charles S. Peirce Society.