My undergraduates open their free will essays the same way every term: "The problem of free will has been debated since time immemorial."

It hasn't. Socrates never mentions it. It isn't in Plato or Aristotle.

Not because they missed it — because they had no concept of will for it to be free or unfree. The thing you assume is the most basic fact about being a person turns out to have a start date.