Any investigation into Human Personality of a scope less than this can be included under the heads of Physiology or Psychology which are prepared to investigate any conceivable intricacy in the mental or bodily states of the living.
It is only when the investigator refuses to be limited by bodily death that Psychic science differentiates itself as a separate study.
I do not propose to consider here whether psychical research has yet given any satisfactory answer to the above mentioned questions or even whether there is any considerable chance of its ever being able to do so.
I merely wish to point out the nature of the problems with which it is concerned and which alone distinguish it as a separate science.
It follows that any hypothesis advanced with a view to co-ordinating the observed facts may find itself called upon to give an intelligible explanation of discarnate personalities, that is to say of human personalities not functioning through the flesh and blood bodies in which we are accustomed to meet them.
So far as our present knowledge goes and on the balance of all the available evidence I am inclined to think that this necessity is at least imminent.
The adoption of some form of working hypothesis is moreover imperative in the light of scientific history.
All who are interested in psychical research will agree that it is in the highest degree desirable that it should be recognised as a Science of a dignity commensurate with its intrinsic importance and on a level with the sciences more generally accepted as such.
That it has not, hitherto, attained this position in the eyes of the world in general is largely due to the fact that it has not yet fully reached that stage of development which chiefly distinguishes a science properly so called from mere speculatory observation.