(1) The author seeks to gain a practical advantage for himself; he wishes to deceive the reader of the document, in order to persuade him to an action, or to dissuade him from it; he knowingly gives false information: we then say the author has an interest in deceiving. This is the case with most official documents. Even in documents which have not been composed for a practical purpose, every interested statement has a chance of being mendacious. In order to determine which statements are to be suspected, we are to ask what _can_ have been the general aim of the author in writing the document as a whole; and again, what can have been his particular purpose in making each of the separate statements which compose the document. But there are two natural tendencies to be resisted. The first is, to ask what interest the author could have _had_ in lying, meaning what interest should _we_ have had in his place; we must ask instead what interest can he have _thought_ he had in lying, and we must look for the answer in his tastes and ideals. The other tendency is to take sole account of the _individual_ interest of the author; we ought, however, to remember that the author may have given false information in order to serve a _collective_ interest. This is one of the difficulties of criticism. An author is a member at one and the same time of several different groups, a family, a province, a country, a religious denomination, a political party, a class in society, whose interests often conflict; we have to discover the group in which he took most interest, and for which he worked. (2) The author was placed in a situation which compelled him to violate truth. This happens whenever he has to draw up a document in conformity with rule or custom, while the actual circumstances are in some point or other in conflict with rule or custom; he is then obliged to state that the conditions were normal, and thus make a false declaration in respect of all the irregularities. In nearly every report of proceedings there is some slight deviation from truth as to the day, the hour, the place, the number or the names of those present. Most of us have observed, if not taken part in, some of these petty fictions. But we are too apt to forget them when we come to criticise documents relating to the past. The _authentic_ character of the documents contributes to the illusion; we instinctively make _authentic_ a synonym of _sincere_. The rigid rules which govern the composition of every authentic document seem to guarantee sincerity; they are, on the contrary, an incentive to falsify, not the main facts, but the accessory circumstances. From the fact of a person having signed a report we may infer that he agreed to it, but not that he was actually present at the time when the report mentions him as having been present.