A parable, about a boy with a philosophy professor of logic for a dad.
Once upon a time there was a boy with a logical dad. He was camping with his friends in a park one day and they came across a fire. He put his hand over it until it hurt and then said, "Ouch, that's hot!" His friends said, "Yeah."
Then they came to another campfire and he put his hand over it again and said the same thing. His friends gave him an odd look and said, "Yeah, didn't you learn the last time?" He replied, "Well, I would not want to be hasty about generalizing. Maybe, there is one fire that is not hot!"
So he did the same thing again at the next fire and burned his hand.
Then they came to a slope that looked rather slippery. A boy slipped down the side of it a little and said, "Wow, it's slippery alright!" But the one boy said, "Maybe some parts of the slope are not so slippery. I would not want to judge the slope, as so slippery."
Then he slipped down the slippery slope and hurt his ankle.
They finally came to their car to get in and go home. But the one boy with the burned hand and hurt ankle looked at the wheels and said, "Those wheels, they look circular!" The other boys just looked at him again, then got in the car. So he got in too. As they drove away he said, "The circular wheels are spinning, what strange madness is this circular reason that we're going forward!"
One truly philosophical boy replied, "Well, it's quite simple really. All fire is hot. A slippery slope is slippery and circles, well, they are quite circular."