Science, however, blocks our advance in this direction by denying, or at least refusing to admit, the existence of the spiritual world, or world of causes: because, being spiritual, it is not sensible, or cognizable in sense. Science admits only material causes, or the changes wrought in matter by itself. If we ask what is the cause of a material cause, we are answered that it is a supposed entity called Force, concerning which there is nothing further to be known. At this point, then, argument (on the material plane) comes to an end, and speculation or assumption begins. Science answers its own questions, but neither can nor will answer any others. And upon what pretence do we ask any others? We ask them upon two grounds. The first is that some people,--we might even say, most people,--would be glad to believe in supersensuous existence, and are always on the alert to examine any plausible hypothesis pointing in that direction: and secondly, there exists a vast amount of testimony (we need not call it evidence) tending to show that the supersensuous world has been discovered, and that it endows its discoverers with sundry notable advantages. Of course, we are not obliged to credit this testimony, unless we want to: and--for some reason, never fully explained--a great many people who accept natural mysteries quite amiably become indignant when requested to examine mysteries of a much milder order. But it is not my intention to discuss the limits of the probable; but to swallow as much as possible first, and endeavor to account for it afterwards.