But, nevertheless, neither those who believe on vague grounds nor those who believe on definite grounds that the question might possibly be solved, or has actually been solved, by human observation of objective facts, have hitherto made any serious attempt to connect and correlate that belief with the general scheme of belief for which Science already vouches. They have not sought for fresh corroborative instances, for analogies, for explanations; rather they have kept their convictions on these fundamental matters in a separate and sealed compartment of their minds, a compartment consecrated to religion or to superstition, but not to observation or to experiment. It is my object in the present work--as it has from the first been the object of the Society for Psychical Research, on whose behalf most of the evidence here set forth has been collected,--to do what can be done to break down that artificial wall of demarcation which has thus far excluded from scientific treatment precisely the problems which stand in most need of all the aids to discovery which such treatment can afford. Yet let me first explain that by the word "scientific" I signify an authority to which I submit myself--not a standard which I claim to attain. Any science of which I can here speak as possible must be a _nascent_ science--not such as one of those vast systems of connected knowledge which thousands of experts now steadily push forward in laboratories in every land--but such as each one of those great sciences was in its dim and poor beginning, when a few monks groped among the properties of "the noble metals," or a few Chaldean shepherds outwatched the setting stars. What I am able to insist upon is the mere Socratic rudiment of these organisms of exact thought--the first axiomatic prerequisite of any valid progress. My one contention is that in the discussion of the deeper problems of man's nature and destiny there ought to be exactly the same openness of mind, exactly the same diligence in the search for objective evidence of any kind, exactly the same critical analysis of results, as is habitually shown, for instance, in the discussion of the nature and destiny of the planet upon which man now moves. Obvious truism although this statement may at first seem, it will presently be found, I think, that those who subscribe to it are in fact committing themselves to inquiries of a wider and stranger type than any to which they are accustomed;--are stepping outside certain narrow limits within which, by ancient convention, disputants on either side of these questions are commonly confined.