Then they took me into the laboratory where they were dissecting brains, and they showed me that this man had a certain spot in his brain that was decayed and therefore he was mad, and another man had a cavity in his skull and therefore he became mad too. I asked them whether it was the decay that caused the madness, or the madness that caused the decay. At first they were astonished, but then they thought that there might be something in my philosophy.