What is apoha, and how can a word mean something by excluding everything else?
I'm a poet and new to formal philosophy, so please be gentle. In a seminar on translation someone mentioned that the Buddhist philosopher Dignāga held that the word “cow” means something like “not non-cow”. Everyone nodded. I laughed, because it sounded like a riddle, and then realised nobody else was laughing.
I'd like to understand it properly. How can a word get its meaning by excluding things? Surely to exclude the non-cows I already need to know what a cow is? And why would anyone take that route instead of the obvious one, that “cow” refers to cows?
One more thing. In my literature course we read Saussure, who says that in language there are only differences. Is apoha the same idea from a different century, or am I being misled by a resemblance?