Semiotics is the study of signs and significance. How does something become significant? How does meaning happen? What exactly is meaning? Where does meaning come from?
Since meaning means a whole lot to us, semiotics should too and yet most of us have never heard of this academic discipline.
In everyday life, we have two conflicting assumptions about signs and their meanings. One is that a sign is a thing with intrinsic meaning. The other is that a sign is not a thing but an evolving relationship, an interpretation process that plays out over time. The schools of thought in semiotics reflect these two, very different assumptions.
Between these two approaches the first dominates both in academics and everyday life. When we say "It's a sign," the word "It" usually refers to a thing, a physical something that means and therefore is a code for something else. A sunset is a sign that night is coming. A weather vane is a sign for the direction of wind. The word "Dog" codes for a canine animal. From this perspective it's all writing on the wall, real things that mean something clearly, directly and specifically.
Consistent with this intuition, many semioticians treat signs as coded in one-to-one correspondence to the things they mean. These academics work to catalogue and categorize kinds of signs, so for example a weather vane is an index, a thing that points, and the word dog is a symbol, an arbitrary scribble that in English always codes for canine animal. Semiotics of this sort collaborates with the kind of linguistics practiced by Noam Chomsky, an attempt to reverse engineer all of language into a coding system, the brain's equivalent of a computer code.
Though this is the prevalent school of thought, it can't be the whole story. The other school argues that a sign can't be a coded link between a thing or "sign vehicle" and what it represents because in the right context absolutely anything can become a sign. Heck, even the absence of a thing can become a sign. The absence of your tax return on April 15th means something to the IRS. The absence of an anniversary gift means something to your partner.
And the meaning of a sign can be quite varied. A shovel lying in your yard can mean your teenage son is still careless, the pet hamster has died, someone is cleaning out the garage or a murder has taken place. A sunset can be a sign to knock off work, pour a glass of wine and smooch with one's partner, or that the world is still rotating on its axis. The word "Dog" means different things in dog days, dog tired, dogged, lucky dog, dog and pony, dog-eared, and what's up dawg?, to say nothing of Swedish in which the sound "dog" means "day." There's no one-to-one coding even with "dog," a relatively straightforward word.
Anything can become part of an evolving relationship of significance, but not everything does. To semioticians of this second school (to which I belong), how these relationships of significance form becomes the big question, and I'm pleased to report (elsewhere) on great progress in answering it.
For practical everyday purposes there's something to both schools of thought. Fundamentally, significance has to be the evolved three-way relationship between a sign vehicle, what it means and you, with meaning changing over time. But sign vehicles do stabilize, meaning the same reliable things for lots of people over lots of time, so of course, we would act sometimes as though the sign vehicle is directly coded to its meaning.
It's interesting to watch people shuttle back and forth between the two schools of thought, shifting between absolute meaning-formulas like "X always means Y," and evolving bet-assertions like "In this case, at this time I'm going to bet that X is best interpreted as Y," for example between saying "Wearing those pants means he's gay" and "I suspect he's gay," between saying "If he's Muslim, he's a terrorist," and saying "Given all we know about him, I am thinking he's a terrorist," between saying "Oil executives are all self-serving liars" and saying "Judging from all the signs, I'm betting this oil executive is a self-serving liar," between saying "Forgetting an anniversary always means the relationship is dead," and saying "In this case, I'm betting that you missing our anniversary means our relationship is dead."
The former approach allows no room for reinterpretation. It assumes the sign vehicle always and forever means the same thing. The latter approach, though it can be plenty firm, does allow some room for reinterpretation, which may explain why the latter approach often looks weak in debate. If you're arguing over interpretation with someone who doesn't believe in interpretation, someone who believes there is one right way to read a sign and all the rest are just mistakes, leaving your mind slightly ajar is going to make you look the most ready to surrender.
Call it the "Absolute advantage," a term with two meanings, the absolute negotiation advantage surrendered to those who are absolute. The absolute advantage is unfair, unjustified and dangerous. The "X means Y" school breeds fundamentalist bullying that has caused the world a lot of trouble and still does. I'm interested in how we interpreters can, counter the absolute advantage. The conservative pundit William F. Buckley ridiculed the liberal as "someone who doubts his prinicples even as he's acting on them." I agree with his discription but not his ridicule. One should doubt one's principles even as one acts on them. That's a virtue not a vice and it shouldn't be turned into a disadvantage in debating fundamentalists of any stripe, liberal or conservative.
Meanings do evolve. People think evolution is about how things change, but evolution is at least as much about how things stay the same over time. Evolution is really about the tension between stability and change. Semiotics as the study of how meaning evolves offers us scientific hints at the relationship between stability and change, determinism and free will, yang assertion and yin flexibility, and politically, conservatism and conservationism on the one hand and liberalism and libertarianism on the other, the two schools we swim in all the time in the great and wonderful seas of meaning.