What it is
A prisoner sentenced to death wins a reprieve by promising to teach the king’s horse to talk within a year. Another prisoner asks why he made such an impossible bargain. “A lot can happen in a year. The horse might die. The king might die. I might die. Or the horse might talk!”
David Deutsch’s point: the prisoner’s real enemy is insufficient knowledge, and some of the opportunities that progress brings are inconceivable in advance. He might not teach the horse to talk, but he might discover something else entirely.
How it shows up for me
It’s my favorite argument for buying time. When a problem looks impossible, I ask whether I can make a deal that gets me a year. Things change, and I learn.