But although thus compelled, in the absence of conclusive data in regard to _the cause_ of the so-called "Spiritual Phenomena," to refrain from making any positive affirmation in regard to this part of the subject, I may add that while the general assertion of its spiritual nature, on the part of the occult force which, within the last quarter of a century, has thus manifested itself all over the globe, constitutes a feature of the case which, from its universality, merits the attention of the impartial investigator--the history of the human race, from the earliest ages, furnishes instances of coincidences, previsions and presentiments of warnings experienced in certain critical moments, of apparitions more or less distinctly seen, which are stated, on evidence as trustworthy as that which we possess with regard to any other branch of historical tradition, to have occurred, spontaneously, in the experience of all nations, and which may therefore be held to strengthen the presumption of the possibility of communication between incarnate and discarnate spirits. I may also add that my own investigations in the fields of philosophy and of modern astronomy have led me, as is well known, to adopt a personal and individual way of regarding the subject of space and time, the plurality of inhabited worlds, the eternity and ubiquity of the acting forces of the universe, and the indestructibility of souls, as well as of atoms. The everlastingness of intelligent life ought to be regarded as the result of the harmonious succession of sidereal incarnations. Our earth being one of the heavenly bodies, a province of planetary existence, and our present life being a phase of our eternal duration, it appears only natural (the _super_natural does not exist) that there should exist a permanent link between the spheres, the bodies, and the souls of the universe, and therefore altogether probable that the existence of this link will be demonstrated, in course of time, by the advance of scientific discovery. It would be difficult to over-rate the importance of the questions thus brought forward for consideration; and I have seen with lively satisfaction the noble initiative which, through the formation of your Committee of Inquiry, has been taken by a body of men so justly eminent as the members of the Dialectical Society, in the experimental investigation of these deeply interesting phenomena. I am most happy, therefore, to comply with the tenor of your letter, by sending you the humble tribute of my observations on the subject in question, and thus to have the opportunity of offering to your society the expression of my sincerest good wishes for the speedy elucidation of the mysteries of nature that have not yet been brought within the domain of positive science.