When categories get extended in the course of history, there has to be some sort of cognitive basis for the extension. And for them to be adopted into the system, that is, “conventionalized”, they must make sense to the speakers who are making these innovations part of their linguistic system, which is, after all, a cognitive system. Chances are, the kinds of cognitive operations used to extend categories are pretty much the ones we have discussed. At the time the extensions of the category occurs, such mechanisms are quite real.
- Lakoff (1987), a pag.111