J. B. Rhine

What Rhine did that his predecessors had not was reduce the claim to something a clerk could score. The instrument was a deck of twenty-five cards designed by his Duke colleague Karl Zener, five each of five symbols, so that a run through the deck had an expected score of exactly five hits by chance and any subject's performance could be stated as a departure from that number in standard deviations.

Where the Society for Psychical Research had spent fifty years arguing about the credibility of witnesses to single dramatic events, Rhine argued about arithmetic accumulated over hundreds of thousands of low-stakes guesses, which meant the dispute could in principle be settled rather than merely continued. He also separated the conditions carefully: a subject guessing a card nobody had looked at was tested for clairvoyance, a subject guessing a card an agent was watching for telepathy, and a subject guessing the order a deck would take after shuffling for precognition, and he treated these as distinct claims requiring distinct designs. The vocabulary followed the method. His 1934 monograph made extra-sensory perception and its abbreviation ESP ordinary English, and he took the German term parapsychology as the name for the whole enterprise in preference to psychical research, precisely because it sounded like a laboratory discipline rather than a seance. Whether the effect he reported was real remains contested; that he changed what counted as an argument about it is not.

The attack on the Duke results began almost at once and came in three forms: that the cards could be read from the back or from imperfections in printing, that scores were recorded by people who knew the target, and that the statistics rested on runs selected after the fact. Attempted replications elsewhere went badly for Rhine, most publicly a large series at Princeton in which more than twenty-five thousand trials produced nothing above chance. Rhine's response was procedural rather than rhetorical: opaque screens between subject and experimenter, mechanical shuffling, duplicate independent scoring, and greater physical distance. He founded the Journal of Parapsychology in 1937 partly so that negative results and methodological criticism would have somewhere to appear inside the field rather than only outside it. The episode that most divides opinion about him came late.

In 1974 Walter J. Levy, whom Rhine had installed as director of his institute and treated as his successor, was caught by his own junior colleagues tampering with recording equipment to inflate results. Rhine investigated, dismissed him, and published the exposure in his own journal. Critics read the affair as showing how easily the field's results could be manufactured and how long it took to notice; Rhine's defenders read his handling of it as the behaviour of someone who wanted an answer rather than a verdict. Both readings survive, and the atlas records the dispute rather than settling it.