Abstract :
Psychical research is a strange subject (and the study and investigation of extra-sensory perception (e.s.p.) is part of it) in that it sometimes leads to a phenomenon to which few other subjects do - the holding of firm opinions in an almost complete absence of knowledge about it. Views about it sometimes seem to be based on a feeling that we know all the laws of nature and that claimed facts that do not fit must be wrong: that e.s.p. cannot occur and therefore that it does not occur. It is hardly necessary to point out to professional engineers how totally unreasonable and unscientific such prejudgments are. Each question must be settled by appealing to the facts rather than to a priori reasoning. This principle is at the heart and core of modern science
