"A horse that solves correctly problems in multiplication and division by means of tapping. Persons of unimpeachable honor, who in the master's absence have received responses, and assure us that in the process they have not made even the slightest sign. Thousands of spectators, horse-fanciers, trick-trainers of first rank, and not one of them during the course of many months' observations are able to discover any kind of regular signal. That was the riddle. And its solution was found in the unintentional minimal movements of the horse's questioner." Authors who, from today's perspective and in the face of current research, were far ahead of their time were often misunderstood or simply ignored by their contemporaries. And even if an excerpt from an extensive work is always subjective, it still offers a middle ground between subsuming under a catchphrase on the one hand, and intensive preoccupation with the author and his work on the other. If you want to deal intensively with the work, please refer to a reprint.