Charles Leslie (1650-1722) was a nonjuror—an Anglican clergyman who refused to take the oath of allegiance to William and Mary after the revolution in 1688 and, in consequence, lost his benefice. In this brief and vigorous work, Leslie proposes four tests for determining whether a reported event is an actual miracle:

  1. That the matter of fact be such, that men’s outward senses, their eyes and ears may be judges of it.
  2. That it be done publicly in the face of the world.
  3. That not only public monuments be kept up in memory of it, but some outward actions be performed.
  4. That such monuments, and such actions or observances be instituted, and do commence from the time, that the matter of fact was done.

The first two rules, Leslie explains, “make it impossible for any such matter of fact to be imposed upon men at the time, when such fact was said to be done, because every man’s eyes and senses would contradict it.” The latter two rules assure those of us who come after that the account was not invented subsequent to the time of the purported event. In a later work, Deism Refuted, Leslie supplemented these with four more marks in order to show how high a standard the evidence for the gospels met.

The Preface to the edition of the Short and Easy Method with the Deists (1815) linked above contains valuable material regarding both the origin and the influence of Leslie’s work. The story of its origin is worth quoting here:

It was the fortune of Mr. Leslie to be acquainted with the Duke of Leeds of that time; who observed to him that, although he was a believer of the Christian religion, he was not satisfied with the common methods of proving it; that the argument was long and complicated; so that some had neither leisure, nor patience to follow it, and others were not able to comprehend it; that, as it was the nature of all truth to be plain and simple, if Christianity were a truth, there must be some short way of showing it to be so; and he wished Mr. Leslie would think of it. Such a hint to such a man, in the space of three days, furnished a rough draught of the Short and Easy Method with the Deists; which he presented to the Duke; who looked it over, and then said, “I thought I was a Christian before, but I am sure of it now; and, as I am indebted to you for converting me, I shall henceforth look upon you, as my spiritual father.” And he acted accordingly; for he never came into his company afterward without asking his blessing.

Leslie’s Short and Easy Method produced a powerful effect and was instrumental in the conversion of the well-known deist Charles Gildon. The 8th edition is available here.