" And all I’m saying is that it is within our capability to survive. I don’t guarantee it. Prophecy is a lost art. And I don’t know what the probabilities are that we will go one way or another. And no one says it’s easy. But it is clear, as Einstein said, that if we do not make a change in our way of thinking, all is lost. "

― Carl Sagan , The Varieties of Scientific Experience: A Personal View of the Search for God