In his lectures recorded in the book Historical Evidences of the Truth of the Scripture Records, p. 39, (https://archive.org/details/historicaleviden1862rawl), George Rawlinson outlines 4 laws or degrees of credibility when examining a historical record. I have quoted them below.
Would these assertions be considered accurate today? Is there anything credible historians today would add or remove from these four statements?
When the record which we possess of an event is the writing of a contemporary, supposing that he is a credible witness, and had means of observing the fact to which he testifies, the fact is to be accepted, as possessing the first or highest degree of historical credibility. Such evidence is on a par with that of witnesses in a court of justice, with the drawback, on the one hand, that the man who gives it is not sworn to speak the truth, and with the advantage, on the other, that he is less likely than the legal witness to have a personal interest in the matter concerning which he testifies.
When the event recorded is one which the writer may be reasonably supposed to have obtained directly from those who witnessed it, we should accept it as probably true, unless it be in itself very improbable. Such evidence possesses the second degree of historical credibility.
When the event recorded is removed considerably from the age of the recorder of it, and there is no reason to believe that he obtained it from a contemporary writing, but the probable source of his information was oral tradition; still, if the event be one of great importance, and of public notoriety, if it affected the national life, or prosperity, —especially if it be of a nature to have been at once commemorated by the establishment of any rite or practice, —then it has a claim to belief as probably true, at least in its general outline. This, however, is the third, and a comparatively low, degree of historical credibility.
When the traditions of one race, which, if unsupported, would have had but small claim to attention, and none to belief, are corroborated by the traditions of another, especially if a distant or hostile race, the event which has this double testimony obtains thereby a high amount of probability, and, if not very unlikely in itself, thoroughly deserves acceptance. The degree of historical credibility in this case is not exactly commensurable with that in the others, since a new and distinct ground of likelihood comes into play. It may be as strong as the highest, and it may be almost as weak as the lowest, though this is not often the case in fact. In a general way we may say that the weight of this kind of evidence exceeds that which has been called the third degree of historical probability, and nearly approaches to the second.
Upon further reading I see that he adds a 5th rule, on page 42, that historians go by (but that he disagrees with):
5.No just perception of the true nature of history is possible, without a perception of the inviolability of the chain of finite causes, and of the impossibility of miracles.