The (mistaken) conflation of a symbol with the object or concept it represents.
The picture shows a tobacco pipe against a monochrome background. Underneath is written: “Ceci n’est pas une pipe” (French: “This is not a pipe”).
In this context, the solution to this apparent contradiction is of course quite obvious: it is indeed not a pipe, but the picture of a pipe.
Symbols are principally not the identical with the object they symbolise: The word “tree” is not a tree but a word, just as the image of a pipe is not a pipe but an image.
Even in the example above, where the distinction between the object and its image should actually be quite easy to comprehend, most viewers first tend to interpret this apparent self-contradiction as a form of surrealist aspect of the painting (which is of course encouraged by the fact that the artist is known as a representative of surrealism in painting).
It becomes even more difficult when the symbols also refer to abstract facts (e.g. at a different level of abstraction). In such cases it can be difficult even for experts to recognise this condition.
This concerns, for example, mathematical models of certain physical or even economic phenomena: these models are not the phenomena, but they are symbolic representations that seek to represent or model the actual phenomena.
Reverse semiotic error
The conflation can also go in the opposite direction, i.e. that a concrete phenomenon is confused with the abstract concept for it.
Homologues/autologues: The word “word” is exactly what it describes, namely a word. Similar self-describing symbols can also be well imagined in other contexts, such as a sign that says: “sign”.
This section is still in progress and will be added later.