Why is the use/mention distinction important? As far as I can tell, it goes back to Quine, who was very big on it. Some people since him have picked up on it and used it to argue for various things, such as Harman’s sharp distinction between inference and implication. I have a vague sense that there is a connection between it and Quine’s extensionalism. Both are used as criticisms of modal logic. Modal logic was, according to him, conceived in the sin of use/mention confusion. But, modal logic has been vindicated. What has the use/mention distinction given us? Is it just an artifact of curmudgeonly Quinean philosophy? I currently have no idea.

On a related note, I had an odd experience recently when I realized that my entire undergrad logic education, including a couple modal logic courses in the Amsterdam style, never once touched upon use/mention.