On the probable inaccuracies of an author, general indications may be obtained from an examination of his writings. This examination will show us how he worked: whether he was capable of abstraction, reasoning, generalisation, and what were the mistakes he was in the habit of making. In order to determine the value of the data, we must criticise each statement separately; we must imagine the conditions under which the author observed, and ask ourselves whether he was able to procure the necessary data for his statement. This is an indispensable precaution in dealing with large totals in statistics and descriptions of popular usages; for it is possible that the author may have obtained the total he gives by a process of conjectural valuation (this is the ordinary practice in stating the number of combatants or killed in a battle), or by combining subsidiary totals, all of which were not accurate; it is possible that he may have extended to a whole people, a whole country, a whole period, that which was true only of a small group known to him.[155]
VI. These two first series of questions bearing on the good faith and the accuracy of the statements in the document are based on the supposition that the author has observed the fact himself. This is a feature common to all reports of observations in the established sciences. But in history there is so great a dearth of direct observations, of even moderate value, that we are obliged to turn to account documents which every other science would reject.[156] Take any narrative at random, even if it be the work of a contemporary, it will be found that the facts observed by the author are never more than a part of the whole number. In nearly every document the majority of the statements do not come from the author at first hand, but are reproductions of the statements of others. Even where a general relates a battle in which he commanded, he does not communicate his own observations, but those of his officers; his narrative is in a large measure a "second-hand document."[157]
In order to criticise a second-hand statement it is no longer enough to examine the conditions under which the author of the document worked: this author is, in such a case, a mere agent of transmission; the true author is the person who supplied him the information. The critic, therefore, must change his ground, and ask whether the informant observed and reported correctly; and if he too had the information from some one else (the commonest case), the chase must be pursued from one intermediary to another, till the person is found who first launched the statement on its career, and with regard to him the question must be asked: Was he an accurate observer?
Logically such a search is not inconceivable; ancient collections of Arab traditions give lists of their successive guarantors. But, in practice, lack of documents nearly always prevents us from getting as far as the observer of a fact; the observation remains anonymous. A general question then presents itself: How are we to criticise an anonymous statement? It is not only "anonymous documents" with which we are concerned, where the composition as a whole is the work of an unknown author; even when the author is known, this question arises with respect to each statement of his drawn from an unknown source.
Criticism works by reproducing the conditions under which an author wrote, and has hardly anything to take hold of where a statement is anonymous. The only method left is to examine the general conditions of the document. We may inquire whether there is any feature common to all the statements of a document indicating that they all proceed from persons having the same prejudices or passions: in this case the tradition followed by the author is biassed; the tradition followed by Herodotus has both an Athenian bias and a Delphic bias. In respect of each fact derived from such a tradition we must ask whether it has not been distorted by the interest, the vanity, or the prejudices of the group concerned. We may even ignore the author, and ask whether there was anything likely to make for or against correct observation, common to all the men of the time and country in which the observation must have been made: for example, what means of information, and what prejudices, had the Greeks of Herodotus' time with respect to the Scythians.
The most useful of all these general inquiries has reference to that mode of transmitting anonymous statements which is called tradition. No second-hand statement has any value except in so far as it reproduces its source; every addition is an alteration, and ought to be eliminated. Similarly, all the intermediary sources are valueless except as copies of the original statement founded directly on observation. The critic needs to know whether this transmission from hand to hand has preserved or distorted the original statement; above all, whether the tradition embodied in the document was written or oral. Writing fixes a statement, and ensures its being transmitted faithfully; when a statement is communicated orally, the impression in the mind of the hearer is apt to be modified by confusion with other impressions; in passing from one intermediary to another the statement is modified at every step,[158] and as these modifications arise from different causes, there is no possibility of measuring or correcting them.
Oral tradition is by its nature a process of continual alteration; hence in the established sciences only written transmission is accepted. Historians have no avowable motive for proceeding differently, at any rate when it is a case of establishing a particular fact. We must therefore search documents for statements derived from oral tradition in order that we may suspect them. We rarely have direct information as to statements being thus derived; authors who borrow from oral tradition are not anxious to proclaim the fact.[159] There is thus only an indirect method, and that is to ascertain that written transmission was impossible; we may then be sure that the fact reached the author only by oral tradition. We have therefore to ask the question: In this period and in this group of men was it customary to commit to writing facts of this kind? If the answer is negative, the fact considered rests on oral tradition alone.
The most striking form of oral tradition is legend. It arises among groups of men with whom the spoken word is the only means of transmission, in barbarous societies, or in classes of little culture, such as peasants or soldiers. In this case it is the whole group of facts which is transmitted orally and assumes the legendary form. There is a legendary period in the early history of every people: in Greece, at Rome, among the Germanic and Slavonic races, the most ancient memories of the people form a stratum of legend. In periods of civilisation popular legends continue to exist in reference to events which strike the imagination of the people.[160] Legend is exclusively oral tradition.
When a people has emerged from the legendary period and begun to commit its history to writing, oral tradition does not come to an end, but only applies to a narrower sphere; it is now restricted to facts which are not registered, whether because they are by their nature secret, or because no one takes the trouble to record them, such as private actions, words, the details of events. Thus arise anecdotes, which have been named "the legends of civilised society." Like legends they have their origin in confused recollections, allusions, mistaken interpretations, imaginings of all kinds which fasten upon particular persons and events.
Legends and anecdotes are at bottom mere popular beliefs, arbitrarily attached to historical personages; they belong to folk-lore, not to history.[161] We must therefore guard against the temptation to treat legend as an alloy of accurate facts and errors out of which it is possible by analysis to extract grains of historical truth. A legend is a conglomerate in which there may be some grains of truth, and which may even be capable of being analysed into its elements; but there is no means of distinguishing the elements taken from reality from those which are the work of imagination. To use Niebuhr's expression, a legend is "a mirage produced by an invisible object according to an unknown law of refraction."