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.
Soap and education are not as sudden as a massacre, but they are more deadly in the long run. Training is everything. The peach was once a bitter almond; cauliflower is nothing but cabbage with a college education.
If I were required to guess off-hand, and without collusion with higher minds, what is the bottom cause of the amazing material and intellectual advancement of the last fifty years, I should guess that it was the modern-born and previously non-existent disposition on the part of men to believe that a new idea can have value.