The long and frankly rather tedious debate between Dizzy and Tim Ireland over at Dizzy's blog reminds me of the old joke about the Engineer, the Physicist and the Mathematician on a train in Scotland. It's their first trip.
They see a black sheep on the side of a mountain. "Look!" says the engineer, "all the sheep in Scotland are black". "No, no" says the physicist, "some of the sheep in Scotland are black". The mathematican intones "In Scotland, there is a sheep, at least one side of which is black".
My training is in Maths by the way!