Molière described the man who had been speaking prose for more than 40 years without knowing it. BMJ readers are probably similarly unaware that they are mostly positivists, subscribing to the doctrine that man can have no knowledge of anything but phenomena. But inside every positivist there may be a shaman (a doctor-priest working by magic) trying to get out. This Christmas issue—with its emphasis on the paranormal—suggests that's the case.

Leonard Leibovici started his experiment by abandoning the idea that time is …