Evolution is a blind giant who rolls a snowball down a hill....

Evolution is a blind giant who rolls a snowball down a hill. The ball is made of flakes-circumstances. They contribute to the mass without knowing it. They adhere without intention, and without foreseeing what is to result. When they see the result they marvel at the monster ball and wonder how the contriving of it came to be originally thought out and planned. Whereas there was no such planning, there was only a law: the ball once started, all the circumstances that happened to lie in its path would help to build it, in spite of themselves.