In order to believe a miracle, it is not enough merely to have seen it; for a man may be deceived. A fool is often called a dealer in wonders; and not merely do many excellent persons think that they have seen what they have not seen, and heard what was never said to them; not only do they thus become witnesses of miracles, but they become also subjects of miracles. They have been sometimes diseased, and sometimes cured by supernatural power; they have been changed into wolves; they have travelled through the air on broomsticks; they have become both _incubi _and _succubi. _
It is necessary that the miracle should have been seen by a great number of very sensible people, in sound health, and perfectly disinterested in the affair. It is above all necessary, that it should have been solemnly attested by them; for if solemn forms of authentication are deemed necessary with respect to transactions of very simple character, such as the purchase of a house, a marriage contract, or a will, what particular and minute cautionary formalities must not be deemed requisite in order to verify things naturally impossible, on which the destiny of the world is to depend?
Even when an authentic miracle is performed, it in fact proves nothing; for Scripture tells you, in a great variety of places, that impostors may perform miracles, and that if any man, after having performed them, should proclaim another God than that of the Jews, he ought to be stoned to death. It is requisite, therefore, that the doctrine should be confirmed by the miracles, and the miracles by the doctrine.
Even this, however, is not sufficient. As impostors may preach a very correct and pure morality, the better to deceive, and it is admitted that impostors, like the magicians of Pharaoh, may perform miracles; it is in addition necessary, that these miracles should have been announced by prophecies.
In order to be convinced of the truth of these prophecies, it is necessary that they should have been heard clearly announced, and seen really accomplished. It is necessary to possess perfectly the language in which they are preserved.
It is not sufficient, even, that you are a witness of their miraculous fulfilment; for you may be deceived by false appearances. It is necessary that the miracle and prophecy should be verified on oath by the heads of the nation; and even after all this there will be some doubters. For it is possible for a nation to be interested in the forgery of a prophecy or a miracle; and when interest mixes with the transaction, you may consider the whole affair as worth nothing. If a predicted miracle be not as public and as well verified as an eclipse that is announced in the almanac, be assured that it is nothing better than a juggler's trick or an old woman's tale.