Humans share knowledge. We trade ideas and exchange information. In The Rational Optimist, Ridley likens this process to sex, and his comparison is more than just florid metaphor. Sex is an exchange of genetic information, a cross-pollination that makes biological evolution cumulative. Ideas too follow this trajectory. They meet and mate and mutate. We call this process learning, science, invention—but whatever the term, it’s exactly what Isaac Newton meant when he wrote: “If I have seen further, it is only because I am standing on the shoulders of giants.”
