A philosopher, a physicist, and a statistician were travelling through Scotland in a train when they saw a black sheep through the window.
“That’s interesting,” said the philosopher, “I see that Scottish sheep are black.”
“Hmm,” said the physicist, “you mean that some Scottish sheep are black.”
“You are both incorrect,” said the statistician. “All we know is that there is at least one sheep in Scotland and that it is black on at least one side.”
At that point the inspector arrived and demanded to see their tickets.
That is the purpose of inspections.