It’s possible to use a category, as associated with a word, only for the purpose of establishing joint attention on a referent—a fundamental aspect of communication to be made clear shortly. For example, let’s say that we’re watching a tennis match on television and I want to tell you who I’d prefer to see win. I may say to you: “I’m cheering for the red-haired player.” The fact that the player that I’m cheering for has red hair may have nothing to do with why I’m cheering for them. It may be nothing more than a useful way to contrast that player with the other player, assuming of course that the other player doesn’t also happen to have red hair. In fact, just pointing, without describing anything at all about the player, could be equally useful: “Who do I hope wins? That player 👉.” Either way, there’s joint attention established on the same referent. We both know who I’m referring to.

If I tell you that I’m cheering for the red-haired player, then I use that category (i.e., “red-haired”) in an expendable way. With joint attention established, the category can be forgotten about. But what if I tell you that red-haired people have a higher pain tolerance on average than people of other hair colors? The category “red-haired” is no longer expendable. It becomes core to what I’m trying to say, no longer just a means to an end.