Mind.

What it means to think, to remember and to understand, and whether a machine does anything of the sort when it puts on the appearance. This line looks at the substrate of intelligence from both sides: the human brain that never quite explains itself and the statistical model that predicts the next word without understanding any of them. Memory, attention, recognition, error, the limits of the computable. The point isn't to decide whether AI thinks, but to sharpen what we call thinking before we go handing out the adjective.