Mr. Harrell describes his lecture: "What is time? It is tempting to look straightaway to some theory or philosophy of time for an answer to this question, even though we 'tell the time' by watches, clocks, and nowadays even phones. And I think that our telling of time indeed tells us something about the nature of time, as well as about the nature of number. In my lecture I hope to show why that is, and what it is."