On Sign and Reference

These three types are distinguished by how they are able to refer to things. An icon refers by virtue of a resemblance between the reference and the sign. For example, a picture of a shoe can serve as an icon for a shoe. If you go into a shoe store in China with a picture cut out of a magazine, you could get that kind of shoe without needing to know a word of Chinese. Really, you wouldn’t even need to bring the cutout; you could just pick the pair of shoes you want and bring it to the cashier. This means that a thing can be an icon for itself. This kind of usage is called “quoting” for some reason.

Quotes and icons will get you though the store, but how do you find the store in the first place? Try looking for building with some placard or plywood board out front. Specifically, a placard with a picture of a shoe on it. In this case, the relationship between sign and signified is less direct. Before, you had picture of an item and the item. This time, the relationship is between a picture of a thing and a place where you get things of that kind. There’s still a connection, but it is less immediate and subject to interpretation. (For example, the sign might be for a dance studio.) A sign used in this way is called an index. Some indices are specific: a picture of a shoe needs to point to some shoe related thing (even if the relationship is as tenuous as a thing and a place were the people use that thing to practice dancing). Some indices are more general: the words “this” and “that” are indexical but what they refer to is context dependent. Still, there must be something that connects the sign to its reference. We call this the sense of the sign. The sense is a context specific aspect of the index that lets us determine its reference.

For indices, the relationship between sign and signified is fairly direct. When the relationship is oblique or arbitrary, we say that the sign is a symbol. Symbols are characterized by their arbitrariness. So, the word “this” is almost a symbol. There’s nothing about the word itself that shows what this means unless you speak English in which case the sense of “this” is well defined though its reference is context dependent. Thus, the real difference between indices and symbols is how arbitrary they are. For indices the sense is pretty much fixed. Icons, similarly, except more so. Something is an icon by virtue of resemblance—like a picture. (However, a picture wouldn’t serve as a very good icon for a blind person, they don’t have the context.) Rather than being three fundamentally different types; icon, index, and symbol are just at different regions on a continuum. Symbols are singled out by an emphasis on the arbitraryness: the symbol’s sense depends on the context of its use.

Thus, on the icon-index-symbol continuum we have two extremes. On the one side, are quotations: the case where a thing serves as a sign for itself. On the other side, we have symbol systems: the case where the relationship between sign and signified is completely arbitrary and potentially subject to change. In the middle, we have indices: things that point by virtue of a given context.

Since I’ve been out of town and haven’t posted for quite some time, I’ll leave this entry at that. Next time, we’ll use these ideas about sign and reference to build a simple language for the case structures we talked about last time. The language will start out very simple, but even in its simplest form, we’ll discover that it’s Turing complete.