Other Minds: The Octopus and the Evolution of Intelligent Life

A blend of natural history, diving observation and philosophy of mind, drawing on the author's years of watching octopuses and cuttlefish in the sea off Australia. Its starting point is that cephalopods evolved large nervous systems and complex behaviour independently of vertebrates, so meeting an octopus is probably the closest we can come to meeting an intelligent alien. Godfrey-Smith traces the history of animal life from single cells through the Ediacaran and Cambrian periods, asking when and why nervous systems and subjective experience arose. He describes how most of an octopus's neurons lie in its arms, raising the question of how unified its mind is, and how cuttlefish produce rapid colour displays although they appear to be colour-blind. He suggests that experience evolved gradually rather than switching on at one point, discusses the role of inner speech in human thought, and uses evolutionary theories of ageing to explain why these clever animals live such short lives. The book ends at a site where many octopuses gather, nicknamed Octopolis.

It is an engaging, careful introduction to animal minds and the evolution of consciousness, built around animals whose intelligence evolved along a path very different from ours.