A fantastic journey from the first molecules of life to the human brain, and absolutely enlightening if you want to understand how our cognition came to be.
Bennett tells the story of the brain as five breakthroughs, each built on top of the last. Steering: the first worm-like animals learning to move towards good things and away from bad ones. Reinforcing: early vertebrates learning by trial, error and reward. Simulating: mammals, whose neocortex lets them imagine an action before taking it. Mentalising: primates modelling other minds, and their own. Speaking: humans sharing those simulations with each other through language.
What makes it enlightening rather than merely fascinating is the running parallel with artificial intelligence, the field Bennett comes from. Almost every breakthrough maps onto a problem machine learning has had to solve, from reinforcement learning to world models to theory of mind. Our machines, it turns out, are retracing evolution’s steps, in a different order and a great deal faster.
What stuck with me is how little of intelligence is new. Most of what we think of as clever is old machinery repurposed, and the parts we are proudest of sit on top of a worm’s urge to move towards food. It is a good corrective for anyone who talks about intelligence, human or artificial, as one thing, and it sits close to a theme I keep coming back to: more is different.