
here's how ferdinand de saussure, writing slightly earlier, saw the relation between thought and language:

roland barthes, an interesting theorist who bridges the structuralist/post-structuralist gap in the mid-20th century, used this model:


another more recent semiotic triangle is extended to include the term 'definition'. this one is from 1997 and is credited to Suonnuuti, who i've never heard of before.

here's what i guess could be called a post-structuralist semiotic schema. it's greimas' semiotic square. it's not actually about the structure of a symbol, but the structure of a particular opposition within a text. remember, post-structuralism isn't a philosophy per se, it's just a way of handling texts and their meanings.

and here's an epistemological model of the semiotic triangle that i think tries to explain what an artificial intelligence would have to have in order to understand signs:

i guess the point is that these kinds of models are very vague. what lines and circles mean is pretty debatable and not even very empirically useful. also, the value of using a little picture to talk about symbols seems dubious at best to me. these kinds of diagrams only make sense when they're responding to one another, or when one philosopher says 'but what if it did work like this...' and uses an illustration to demonstrate their difference from some other tradition. someone should probably launch a study of these kinds of diagrams as a form in the semiotic/linguistic/cognitive fields. maybe someone already has...