This book marks a distinction between psychical research, on the one hand, and spiritualism on the other. The two terms are often regarded as synonymous, but they are not. Psychical research aims at being a science, while spiritualism or spiritism is a pronouncement of faith. It is true that psychical research deals with topics which are ignored by ordinary scientific people, but it deals with them according to the methods of science, and arrives at carefully deduced conclusions. The method of science in such a case is to stress all verve cause to the uttermost, and not to assume anything in the smallest degree supernormal unless all normal causes are carefully excluded. Among the normal causes, fraud and inaccuracy of statement have to be strenuously guarded against, and the effort at guarding against them in every new case must seem rather tiresome to those whose experience has shown that supernormal things actually occur. There are some to whom supernormal things are of such frequent occurrence that the prefix seems to them almost unnecessary: things ordinarily so called have become by custom practically normal. Hence they tend to theorize from a different basis, these who rightly call themselves spiritualists start from an assured platform from which occurrences, which to those with less or no experience seem incredible, range themselves among expected phenomena, and are just as intelligible as anything open to ordinary observation. Nevertheless, in presenting the subject to novices, or persons without this experience, it is wise and necessary not to assume any more than they are ready to grant.