The reply to the first clause of the question is sufficiently obvious. We have no experience whatever of psychical phenomena save as manifested in connection with material phenomena. We know of Mind only as a group of activities which are never exhibited to us except through the medium of motions of matter. In all our experience we have never encountered such activities save in connection with certain very complicated groupings of highly mobile material particles into aggregates which we call living organisms. And we have never found them manifested to a very conspicuous extent save in connection with some of those specially organized aggregates which have vertebrate skeletons and mammary glands. Nay, more, when we survey the net results of our experience up to the present time, we find indisputable evidence that in the past history of the visible universe psychical phenomena have only begun to be manifested in connection with certain complex aggregates of material phenomena. As these material aggregates have age by age become more complex in structure, more complex psychical phenomena have been exhibited. The development of Mind has from the outset been associated with the development of Matter. And to-day, though none of us has any knowledge of the end of psychical phenomena in his own case, yet from all the marks by which we recognize such phenomena in our fellow-creatures, whether brute or human, we are taught that when certain material processes have been gradually or suddenly brought to an end, psychical phenomena are no longer manifested. From first to last, therefore, our appeal to experience gets but one response. We have not the faintest shadow of evidence wherewith to make it seem probable that Mind can exist except in connection with a material body. Viewed from this standpoint of terrestrial experience, there is no more reason for supposing that consciousness survives the dissolution of the brain than for supposing that the pungent flavour of table-salt survives its decomposition into metallic sodium and gaseous chlorine.