
Daniel Chandler, Semiotics: The Basics, 2nd Edition, Routledge (London and New York: 2002), p 36-37.
Symbol
“A mode in which the signifier does not resemble the signified but is fundamentally arbitrary or purely conventional—so that this relationship must be agreed upon and learned: e.g. language in general (plus specific languages, alphabetical letters, punctuation marks, words phrases and sentences), numbers, morse code, traffic lights).”
Icon
“A mode in which the signifier is perceived as resembling or imitating the signified (recognisably looking, feeling, tasting or smelling like it)—being similar in possessing some of its qualities: e.g. a portrait, metaphors, cartoon, gestures, dubbed film soundtrack.”
Index
“A mode in which the signifier is not arbitrary but is directly connected in some way (physically or causally) to the signified (regardless of intention)—this link can be observed or inferred: e.g. ‘natural signs'(smoke, thunder, footprints, echoes, medical symptoms (pain, rash, pulse-rate), measuring instruments (thermometer, clock, spirit-level), ‘signals’ (knock on the door, phone ring), pointers (pointing ‘index’ finger, sign post), recordings (photograph, film, tv, audio), personal trademarks (handwriting, catchphrases).”
Chandler (2002)
Adopting Piercean concepts of indexicality and iconicity means no longer isolating the referent, but pointing to something outside of it. Iconicity, in photography, would refer to a perceived resemblance to the referent, whereas indexicality is based on a (perceived) direct connection to it. It allows us to move beyond the boundaries of the Saussurean model of semiotics, one which Roman Jakobson adopted in his structuralist and linguistic framework of semiotics, which was used in early translation theory (by, for example, Umberto Eco).
Thinking about semiotics within a wider triadic, post-structuralist framework allows context to be considered within the processes of meaning-making.
Letters, words and language in general are symbols, they have no direct connection to the signified—the things they refer to. Metaphors or other vehicles for language are considered iconic in that they resemble, or possess some of the qualities that language or words have, which is the thing they refer to. They physically have words in them. Handwriting is indexical, in that it has a direct connection to the things it refers to but is not arbitrary, it is based on a perceived connection to it. Ie the presence of a specific person, an individual who wrote the words. Symbols are visible, Icons are visible? The index relates to the thing outside of itself which is not seen but directly referred to. The index is invisible—perceived, directly connected to, not arbitrary, but invisible.