Douglas Hofstadter: The Nature of Categories and Concepts

Stanford Symbolic Systems Distinguished Speaker Lecture
Thursday, March 6, 2013

Douglas Hofstadter, College of Arts and Sciences Distinguished Professor of Cognitive Science and Comparative Literature. Indiana University

What is a quintessential category? Bird, perhaps? Or maybe chair? And what is a quintessential concept? Two? Number? Prime number?

I'm not trying to put words into your mouth -- I'm just trying to get you to ask yourself these questions. Also, I wonder if by any chance you thought that these are really exactly the same question, in which case you might have wondered why I asked you the same question twice.


Or did you perhaps think something along these lines: "A category is a set of objects
out there in the real world, whereas a concept is a mental entity that gets activated whenever one sees a member of the corresponding category"? In that case, you would essentially be equating a category with the extension of a set, and a concept with the intension of a set. (Those are notions borrowed from mathematical logic and set theory.)

Actually, none of the notions above is at all close to the viewpoint that I wish to convey to you about concepts and categories. My viewpoint is, I think, quite unorthodox and quite radical, and it claims that concepts and categories include many extremely commonplace, dime-a-dozen notions that you might never have thought of as being categories or concepts. (Sorry -- I'm not going to list any of them here; you'll have to come to the talk to find out what I mean!) I will try to convince you that, despite any initial skepticism, these are primordial, quintessential cases, and I hope that this novel view will have a serious impact on what you think thinking is.