Signs
Doug commented a few days ago, regarding Sebeok, “I’m still trying to understand what he means by signs.” That’s a big container of something. I’ve been trying to figure out how to cogently express what I’ve been thinking about regarding signs. To complicate things, I’ve been reading Semiotics and the Philosophy of Language by Umberto Eco. Eco devotes around forty pages to this very question. What is meant by the designation sign?
The basic definition offered by C.S. Peirce is:
Something which stands to somebody for something in some respect or capacity
Peirce’s definition is open enough to accommodate extension to zoosemiotics—something that stands for something could just as easily be a chemical change, a neural impulse, or other biological response. The problem is that such a broad definition encompasses almost everything. Most discussion of signs center on the linguistic sign, which Saussure mapped in this fashion:

Saussure saw the sign as a two-part entity: the signifier (sound pattern, written code, etc.) and the signifed (actual thought, or real thing). The arrows on the sides of the diagram are meant to show the interaction. Each part is modified by the other. Peirce, on the other hand, saw the sign as a three part entity because without an interpreter, the sign is meaningless.
The binary structure of the linguistic sign posited by Saussure has been incredibly influential. Signs, in Saussure’s view, are signs are tools for communication. However, it sets up a map for communication that has a lot of problems:

The basic idea is that signs are a code, encoded by a sender and then decoded by an addressee. The Shannon-Weaver model of technical communication adds a third factor, noise, which interferes with the communication. This model of signs—that they are constructed implicitly for communication—ignores the fact that signs have other attributes. Not all signs operate that way. We are blinded to the complexity of other possible signs by getting locked into this simplistic communication model.
The earliest type of sign designation was that of the symptom. Cold chills and fever are not essentially communicative attempts, but rather signs that a person has a cold. Dark thunderclouds are a sign— a sign that it might rain. It is this broader context of signs that must be used to understand Sebeok’s extension of a “doctrine of signs.” Eco neatly divides this project into a semiotics which deals with the signs themselves, and a separate semiotics that deals with how semiosis occurs—how we deal with making meaning out of signs. Saussure deals strictly with the latter, whereas Sebeok is more interested in the primary nature of signs.
I’m sure I’ve not really done much here but confuse the issue. But I’m trying to write my way through this, not so much to explain it to other people, but to make sure that I understand it myself. Eco teases out some really interesting characteristics for signs (in general) that I’m still working on. I’m sure I’ll bore the crap out of people for a while as I dwell on it.
I’m not certain whether to say thanks or apologise for asking 🙂 I’ll say thanks though as I do have a better understanding now having read this post.
I’m thinking about so-called “natural signs” — leaves blowing in a certain direction, animal spoor — which inclines me to propose thinking of signs as “occasions of inference.” A non-teleological characterization of “signs” seems likely to serve best without pre-determining several questions (about intent and meaning) that ought to be resolved in the course of reflection on semiotics, not at the outset by definitional fiat. . . .