We'd all like to know what it's all about, wouldn't we? And if anyone might be expected to know the answer, surely the (self-proclaimed?) cleverest man in the world should?
But no. Another case where the cup of happiness and eager expectation is dashed from our lips at the last moment...
Incidentally, did you know that Bertrand Russell was the inspiration for Professor Yaffle in Bagpuss?
(What do you mean you don't know who Bertrand Russell is?)