Doctor Mort in “Unfinished Business”

Yesterday, I was walking in the park and I saw a little lad no higher than my thigh, standing at the edge of a great pond, holding a piece of string. A piece of string. And I approached the lad no higher than my thigh and spoke to him. “Lad, why are you standing at the side of this great pond, holding a piece of string?” “Sir this is a boat on the end of this string and it has sunk.” “Then how do you know that its still there if you cannot see it?” “Because, sir, I can feel the tug.”