"Peter Godfrey-Smith is a leading philosopher of science. He is also a scuba diver whose underwater videos of warring octopuses have attracted wide notice. In this book, he brings his parallel careers together to tell a bold new story of how nature became aware of itself. Mammals and birds are widely seen as the smartest creatures on earth. But one other branch of the tree of life has also sprouted surprising intelligence: the cephalopods, consisting...