What we tend to do as a species, as we progress, is to become more and more specialized in what we produce but more and more diversified in what we consume. That saying I got from a wonderful book called Second Nature, years ago by a man named Haim Ofek. I wrote to him and said, “This is an interesting insight. Have you written anything more about it?” He replied, “Well, I think I got that idea from one of your books.”