ESP and flying saucers: A challenge to parapsychologists

It has been claimed that the reason it may be impossible to devise a "repeatable" ESP experiment--one that gives results favorable to ESP in at least a majority of repetitions done by qualified skeptical experimenters--is that variables of personality and of attitude toward ESP in experimenters as well as in subjects affect results and that some experimenters are doomed to failure. On occasion, the necessity of this criterion of repeatability has been blandly denied, although it has been a fundamental requirement of proof in all experimental science. Both flying saucers and ESP may exist, but few trained experimentalists will accept them as proved until they have met all criteria of controlled experimentation, including repeatability of the observations. To obtain this proof the experimenter must accept the responsibility of specifying the conditions under which consistent observations may be made. Since there is no universal negative, an hypothesis of the nature of ESP cannot, be disproved, and the burden of proof rests squarely on the positive claimants. As a major step in furnishing the necessary repeatability for experimental proof of ESP, the author challenges the parapsychologists to settle upon one experimental design--any one that offers adequate control--and to obtain adequate repetitions of it with positive results.