Hitherto, all that we have learnt regarding these occurrences is that their origin is unknown. It will be said that this is not much and that the discovery is nothing to boast of. I quite agree: to imagine that one can explain a phenomena by saying that it is produced by an unknown agency would indeed be childish. But it is already something to have marked its source; not to be still lingering in the thick of a fog, trying any and every direction in order to find a way out, but to be concentrating our attention on a single spot which is the starting-point of all these wonders, so that at each instant we recognize in each phenomenon the characteristic customs, methods or features of the same unknown agency. It is very nearly all that we can do for the moment; but this first effort is not wholly to be despised. 2 It has seemed to us then that it was our unknown guest that expressed itself in the name of the dead in table-turning and in automatic writing and speaking. This unknown guest has appeared to us to take within us the place of those who are no more, to unite itself perhaps with forces that do not die, to visit the grave with the object of bringing thence inexplicable phantoms which rise up in front of us fruitlessly or haunt our houses without telling us why. We have seen it, in experiments in clairvoyance and intuition, suppressing all the obstacles that banish or conceal thought and, through bodies that have become transparent, reading in our very souls forgotten secrets of the past, sentiments that have not yet taken shape, intentions as yet unborn. We have discovered that some object once handled by a person now far away is enough to make it take part in the innermost life of that person, to go deeper and rise higher than he does, to see what he sees and even what he does not see: the landscape that surrounds him, the house which he inhabits and also the dangers that threaten him and the secret passions by which he is stirred. We have surprised it wandering hither and thither, at haphazard, in the future, confounding it with the present and the past, not conscious of where it is but seeing far and wide, knowing perhaps everything but unaware of the importance of what it knows, or as yet incapable of turning it to account or of making itself understood, at once neglectful and overscrupulous, prolix and reticent, useless and indispensable. We have seen it, lastly, although we had hitherto looked upon it as indissolubly and unchangeably human, suddenly emerge from other creatures and there reveal faculties akin to ours, which commune with them deep down in the deepest mysteries and which equal them and sometimes surpass them in a region that wrongly appeared to us the only really unassailable province of mankind, I mean the obscure and abstruse province of numbers.