It will perhaps be well to add the observation, before finishing this preface, that in denying the physical influence of the soul upon the [69] body or of the body upon the soul, that is, an influence causing the one to disturb the laws of the other, I by no means deny the union of the one with the other which forms of them a suppositum; but this union is something metaphysical, which changes nothing in the phenomena. This is what I have already said in reply to the objection raised against me, in the _Memoires de Trevoux_, by the Reverend Father de Tournemine, whose wit and learning are of no ordinary mould. And for this reason one may say also in a metaphysical sense that the soul acts upon the body and the body upon the soul. Moreover, it is true that the soul is the Entelechy or the active principle, whereas the corporeal alone or the mere material contains only the passive. Consequently the principle of action is in the soul, as I have explained more than once in the _Leipzig Journal_. More especially does this appear in my answer to the late Herr Sturm, philosopher and mathematician of Altorf, where I have even demonstrated that, if bodies contained only the passive, their different conditions would be indistinguishable. Also I take this opportunity to say that, having heard of some objections made by the gifted author of the book on _Self-knowledge_, in that same book, to my System of Pre-established Harmony, I sent a reply to Paris, showing that he has attributed to me opinions I am far from holding. On another matter recently I met with like treatment at the hands of an anonymous Doctor of the Sorbonne. And these misconceptions would have become plain to the reader at the outset if my own words, which were being taken in evidence, had been quoted.