Icon, index, symbol

photograph by julie dawn dennis

In the 19th Century C.S. Peirce developed semiotic theory, including three trichotomies of signs.  It is in the second trichotomy in which Peirce applies the terms Icon, Index and Symbol,

I know little of semiotic theory, but I appreciate that Peirce’s theory of signs can be useful when looking at photographs, and in order to begin to understand it I will look at here it in the context of some of my own work.  To remind myself of the system of Icon, Index and Symbol, I begin by referring to a straightforward photograph of a rock.

As Icon:
Following Peirce’s theory, the photograph of a rock is an icon of a rock. The Icon refers to the physical thing, in this case the rock, (as well as the grass, the frost). Here the photograph looks like its subject.

As Index:
It could be said that the rock is indexical of hardness.  The frost of coldness.

As Symbol:
The symbol is psychological; it is learned or habitual and can be removed from its context easily.  In the above image, it could be said that the rock is a symbol of age, of loneliness in its solitary position, or perhaps rejection by being in the cold.  It could also be symbol of strength, resilience, and so on.

Rock, 2019

Revisiting this subject I am reminded that:

“Signs have

a signal aspect, some physical pattern (eg, a sound or visible shape) and a meaning – some semantic content that is implied or `brought to mind’


  • Icons have a physical resemblance between the signal and the meaning
  • Indices have a correlation in space and time with its meaning.
  • Symbols (content words like nouns, verbs and adjectives) are (sound) patterns) that get meaning:

primarily from its mental association with other symbols and
secondarily from its correlation with environmental patterns.”

(Source: www.cs.indiana.edu)

Signs, of course, have their problems too.  A photograph is not the thing itself and we are to be reminded of this as we look beyond the surface of the image to see, in this case, a rock, frost, grass.  Photographs may also be constructions or abstractions, images that don’t look like the subject at all, like Imagined Landscapes, a series created with analogue and digital cameras with a result appearing in some ways a like a fictional landscape. Of course, there was no actual landscape before the lens, but there was an object present at the time that created the shapes within the images when photographed.

from Imagined Landscapes, 2018

As Icon:
The photograph perhaps fails, as it is not a landscape but a shape of an object that appears similar to a landscape; it does not resemble the subject that was placed before the lens barely at all. Instead, the image resembles a lunar or planetary scene, or a landscape of sorts.  According to Umberto Eco, “a sign is anything that can be used to tell a lie” (Eco, 1979, p7), and this is what could possibly be said here, however, Peirce also wrote that the Object does not have to exist in order for something to be a sign.

“An Icon is a sign which refers to the Object that it denotes merely by virtue of characters of its own, and which it possesses, just the same, whether any such Object actually exists or not. It is true that unless there really is such an Object, the Icon does not act as a sign; but this has nothing to do with its character as a sign. Anything whatever, be it quality, existent individual, or law,is an Icon of anything,in so far as it is like that thing and used as a sign of it.” (Peirce, p169)

As Index:
If viewed as a landscape (though there was no iconic landscape to support it) then the indexical characteristic of the apparently lunar scene is nightfall perhaps.

“In so far as the Index is affected by the Object, it necessarily has some Quality in common with the Object, and it is in respect to these that it refers to the Object. It does, therefore, involve a sort of Icon, although an Icon of a peculiar kind; and it is not the mere resemblance of its Object, even in these respects which makes it a sign, but it is the actual modification of it by the Object.” (Peirce, p169)

Perhaps then, the Icon above is acceptable as peculiar to the processes of photography.

As Symbol:
As the symbol is psychological, the symbol here may be one of sleep or dreaminess; one of exploration and entering into the unknown; or its darkness may symbolise fear or dread.

“A Symbol  is a sign which refers to the Object that it denotes by virtue of a law, usually an association of general ideas, which operates to cause the Symbol to be interpreted as referring to that Object […] There must, therefore, be existent instances of what the Symbol denotes, although we must here understand by “existent,” existent in the possibly  imaginary universe to which the Symbol refers.” (Peirce, pp169-170)

Peirce also writes on the Photograph specifically in his text, isolating “instantaneous photographs” as being “exactly like the objects they represent”.  It seems here that he is aware of other types of photograph that would be perhaps more complicated to situate within his semiotic theory. (There may be more on this theme that I have yet to discover in this text).

When discussing the symbolic nature of a zebra and a donkey, whether the zebra can be attributed the same symbolic stubbornness as a donkey, Peirce also acknowledges that the photograph may hinder our application of this symbol, as it does not provide “independent knowledge of the circumstances of the production of the two species” (Peirce, p175)

I am merely beginning to scratch the surface here, and this is an exercise for me in revisiting basic semiotic ideas that I have not thought about for a while.  This is something I will be coming back to.


Eco, U. (1979) A theory of semiotics Bloomington: Indiana University Press (in online presentation PHO702, Is it really real? Falmouth University)

Peirce, C.S. (1986), Philosophical Writings of Peirce, Dover Publications, New York. Available from: ProQuest Ebook Central. [Accessed 5th February 2019].

[Accessed 5th February 2019]