10. The false prophets are not to be found solely amongst incarnates. They are also to be found in even greater numbers amongst the prideful Spirits, who by appearing to be all love and charity, sow disunion and hold back the work of emancipating humanity by infiltrating their absurd doctrines, after having gained a medium's acceptance of them. And in order to further fascinate those whom they desire to delude, so as to give more weight to their theories, they appropriate without scruples those names which Man pronounces only with great respect.
It is these Spirits who scatter a tumult of antagonism amongst groups, impell them to isolate themselves from all others, and look upon them with suspicion. This situation alone is enough to unmask them, since by so proceeding they are the first to offer a clear denial of who they claim to be. Blind therefore are those who allow themselves to fall for so great a hoax.
But there are many other ways in which they maybe recognised. The Spirits of this particular category, to which they say they belong, have to be not only very good but also eminently rational. Well then, put all their doctrines through the test of reason and good sense and see what you have left. You will then agree with me that every time a Spirit indicates things of a utopian, childish, impracticable or ridiculous nature, or formulates a dogma, which the most rudimentary notions of science contradict, as a solution for the problems of humanity, or as a means of achieving their transformation, then these ideas can only come from a very ignorant or lying Spirit.
On the other hand, you may be sure that if the individual does not always appreciate the truth, it is appreciated by the good sense of the masses, which constitutes yet one more criterion. If two principles contradict each other, we can find the measure of value inherent in both by verifying which of the two generates a greater echo and sympathy. Apart from the fact that it would be illogical to admit to oneself that any doctrine whose number of adepts progressively diminishes is more truthful than that of another whose followers continually increase. In desiring that the truth reaches everyone, God has not confined it to a narrow circle, but has made it appear in all places, so that the light shines alongside the darkness.
Repel all those Spirits who present themselves as exclusive counsellors, preaching separation and isolation. They are almost always vain and mediocre Spirits, who seek to impose and dictate to weak and credulous persons by lavishing exaggerated praise upon them, with the aim of fascinating and so dominating them. These are generally Spirits eager for power, who having been despots both publicly or in their own homes, still continue to look for victims to tyrannize, even after death. In general, mistrust all communications which have a mystical and singular character or those which perscribe excentric acts and ceremonies. In all of these cases there is always legitimate motive for suspicion.
Equally you may be sure that when a truth is to be revealed to mankind it is, by way of saying, instantly communicated to all serious groups who have at their disposal serious mediums, and not only to one group at the exclusion of all others. No one can be a perfect medium if they become obsessed, and there is manifest obsession when a medium is only able to receive communication from one specific Spirit, however elevated that spirit pretends to be. Consequently, every medium and all groups who believe themselves to be privileged by reason of the communications they alone obtain, and who moreover, are subject to practises bordering on superstition, undoubtedly find themselves caught up in a well characterized obsession; above all, when the dominating Spirit swaggers under a name which both incarnates and discarnates should honour and respect and not allow reputations to be compromised in this manner.
It is incontestable that by submitting to the crucible of reason and logic all the facts and communications received from Spirit, it becomes an easy matter to reject the errors and absurdities. A single medium may become fascinated or a group deluded; but through severe verification of what is occurring in other groups, the acquiring of knowledge within the subject matter, the analysis of all communications received by the principal mediums of each group, together with the use of logic and the verification of authenticity whenever possible of the most serious Spirit communicators, it is possible to render justice to all falsehoods and trickery from any band of deceiving or malicious Spirits. - ERASTUS, disciple of Saint Paul (Paris, 1862).
(See the second item in the Introduction of this book headed: THE UNIVERSAL VERIFICATION OF THE TEACHINGS OF THE SPIRITS, and also the second part of the THE MEDIUMS' BOOK (1), chapter 23, OBSESSION.)