METAZOA

A philosophical investigation of how animals, from the bottom up, experience the world.

In this follow-up to his previous book, the highly acclaimed Other Minds: The Octopus, the Sea, and the Deep Origins of Consciousness (2016), Godfrey-Smith, professor of history and the philosophy of science at the University of Sydney, rewinds the clock to recount the evolution of consciousness from the time life first appeared 4 billion years ago. Long before nervous systems or even nerves evolved, there was sentience. No living cell is oblivious to what is going on around it, but animals take it to a new level. “Single-celled organisms can track touches, chemicals, light, and even Earth’s magnetic field,” writes the author. “But in animals, sensing saw a transition—it saw several, in fact.” Godfrey-Smith finds the octopus irresistible, leading him to “reflect on different ways of being an animal, and the different kinds of experiences…associated with different animal bodies.” Although widely considered “smart,” the author prefers to describe them as behaviorally complex creatures who love to explore and try things but are not ruminative or “clever.” Fish chose a different path, evolving a missile shape, a nerve cord down the back serving muscles organized for mobility, and a camera eye. Eventually, fish developed recognition, memory, and strategic skills, which they passed on to their descendants who left the ocean. No one knows what fish and land animals think, but when scientists measure their brains waves, they detect “similar rhythmic patterns going on inside them.” Insects, the most numerous animals on land, follow another playbook. Although impressive in actions such as flying and vision, their felt experiences remain largely conjecture. Wound tending has never been witnessed in an insect; after an injury, they just continue with whatever they have to do. We are unsure about whether they feel pain. Godfrey-Smith mixes speculation into the science, but the narrative is consistently insightful.

A lucid journey through the animal world.