This dialogue is on the nature of thought and thinking. The five disputants are Socrates, an imaginary neuroscientist from California (whose opinions reflect those of contemporary cognitive neuroscientists), an Oxford don from the 1950s (who employs the linguistic analytic techniques of his times), a Scottish post-doctoral student, and John Locke (who speaks for himself). The discussion takes place in Elysium in the late afternoon. They examine the idea that thinking is an activity of the mind or the brain, whether the medium of thought consists of words or ideas, whether thoughtful speech is speech accompanied by thought, whether thinking, i.e. reasoning and inferring, is a process, and what is meant by the claim that ‘thinking is the last interpretation’. The dialogue ends when the protagonists go to dinner, but will be resumed after the meal.