“When an apple ripens and falls—what makes it fall? Is it that it is attracted to the ground, is it that the stem withers, is it that the sun has dried it up, that is has grown heavier, that the wind shakes it, that the boy standing underneath wants to eat it? No one thing is the cause. All this is only the coincidence of conditions under which every organic, elemental event of life is accomplished. And the botanist who finds that the apple falls because the cellular tissue degenerates, and so on, will be as right and as wrong as the child who stands underneath and says that the apple fell because he wanted to eat it and prayed for it.”