(This is from the 1908 Catholic Encyclopedia.)
Historical criticism is the art of distinguishing the true from the false concerning facts of the past. It has for its object both the documents which have been handed down to us and the facts themselves. We may distinguish three kinds of historical sources: written documents, unwritten evidence; and tradition. As further means of reaching a knowledge of the facts there are three processes of indirect research, viz.: negative argument, conjecture, and a priori argument.
It may be said at once that the study of sources and the use of indirect processes will avail little for proper criticism if one is not guided chiefly by an ardent love of truth such as will prevent him from turning aside from the object in view through any prejudice, religious, national, or domestic, that might trouble his judgment. The rôle of the critic differs much from that of an advocate. He must, moreover, consider that he has to fulfil at once the duties of an examining magistrate and an expert juryman, for whom elementary probity, to say nothing of their oath, makes it a conscientious duty to decide only on the fullest possible knowledge of the details of the matter submitted to their examination, and in keeping with the conclusion which they have drawn from these details; guarding themselves at the same time against all personal feeling either of affection or of hatred respecting the litigants. But inexorable impartiality is not enough; the critic should also possess a fund of that natural logic known as common sense, which enables us to estimate correctly, neither more nor less, the value of a conclusion in strict keeping with given premises. If, moreover, the investigator be acute and shrewd, so that he discerns at a glance the elements of evidence offered by the various kinds of information before him, which elements often appear quite meaningless to the untrained observer, we may consider him thoroughly fitted for the task of critic. He must now proceed to familiarize himself with the historical method, i. e. with the rules of the art of historical criticism. In the remainder of this article we shall present a brief résumé of these rules apropos of the various kinds of documents and processes which the historian employs in determining the relative degree of certainty which attaches to the facts that engage his attention.
There are two kinds of written documents. Some are drawn up by ecclesiastical or civil authority, and are known as public documents; others, emanating from private individuals and possessing no official guarantee, are known as private documents. Public or private, however, all such documents raise at once three preliminary questions:
(1) authenticity and integrity;
Authenticity and Integrity
Does the document which confronts us as a source of information really belong to the time and the author claimed for it, and do we possess it in the shape in which it left that author's hand? There is little or no difficulty in the case of a document printed during the author's lifetime, and given at once a wide distribution. It is otherwise when, as often happens, the document is both ancient and in manuscript. The so-called auxiliary sciences of history, i. e. palæography, diplomatics, epigraphy, numismatics, sigillography, or sphragistics, furnish practical rules that generally suffice to determine approximately the age of a manuscript. In this preliminary stage of research we are greatly aided by the nature of the material on which the manuscript is written, e. g. papyrus, parchment, cotton or rag paper; by the system of abbreviations employed, character of the hand-writing, ornamentation, and other details that vary according to countries and epochs. It is rare that a document claiming to be an original or an autograph, when submitted to such a series of tests, leaves room for reasonable doubt regarding its authenticity or non-authenticity. More frequently, however, ancient documents survive only in the form of copies, or copies of copies, and their verification thus becomes more complicated. We must pass judgment on each manuscript and compare the manuscripts with one another. This comparison enables us, on the one hand, to fix their age (approximately) by the rules of palæography; on the other, it reveals a number of variant readings. In this way it becomes possible to designate some as belonging to one "family", i. e. as transcribed from one original model, and thus eventually to reconstruct, more or less perfectly, the primitive text as it left the author's hand. Such labour (merely preliminary, after all, to the question of authenticity), were every one forced to perform it, would deter most students of historical science at the very outset. It becomes, however, daily less necessary. Men specially devoted to this important and arduous branch of criticism, and of a literary probity beyond suspicion, have published and continue to publish, with the generous aid of their governments and of learned societies, more or less extensive editions of ancient historical sources which place at our disposal, one might almost say more advantageously, the manuscripts themselves. In the prefaces of these scholarly publications all the known manuscripts of each document are carefully described, classified, and often partially represented in facsimile, thereby enabling us to verify the palæographic features of the manuscript in question. The edition itself is usually made after one of the principal manuscripts; moreover, on each page we find an exact summary (sometimes in apparently excessive detail) of all the variant readings found in the other manuscripts of the text. With such helps the authenticity of a work or of a text may be discussed without searching all the libraries of Europe or tiring one's eyes in deciphering the more or less legible handwriting of the Middle Ages.
The manuscripts once counted and classified, we must examine whether all, even the most ancient, bear the name of the author to whom the work is generally attributed. If it be lacking in the oldest, and be found only in those of a later date, especially if the name offered by the earlier manuscripts differ from that given by later copyists, we may rightly doubt the fidelity of the transcription. Such doubt will often occur apropos of a passage not met in the oldest manuscripts, but only in the more recent, or vice versa. Unless we can otherwise explain this divergency, we are naturally justified in suspecting an interpolation or a mutilation in the later manuscripts. While the authenticity of a work may be proved by the agreement of all its manuscripts, it is possible further to confirm it by the testimony of ancient writers who quote the work under the same title, and as a work of the same author; such quotations are especially helpful if they are rather extensive and correspond well to the text as found in the manuscripts. On the other hand, if one or several of such quoted passages are not met with in the manuscript, or if they be not reproduced in identical terms, there is reason to believe that we have not before us the document quoted by ancient writers or at least that our copy has suffered notably from the negligence or bad faith of those who transcribed it. To these signs of authenticity, called extrinsic because they are based on testimony foreign to the author's own work, may be added certain intrinsic signs based on an examination of the work itself. When dealing with official and public acts care must be taken to see that not only the handwriting, but also the opening and closing formulæ, the titles of persons, the manner of noting dates, and other similar corroborative indications conform to the known customs of the age to which the document is attributed. Amid so many means of verification it is extremely difficult for a forgery to escape detection. Words and phraseology furnish another test. Each century possesses its own peculiar diction, and amid so many pitfalls of this nature it is scarcely possible for the forger to cloak successfully his misdeed. This is also true for the style of each particular author. In general, especially in the case of the great writers, each one has his own peculiar stamp by which he is easily recognized, or which at least prevents us from attributing to the same pen compositions quite unequal in style. In the application of this rule, no doubt, care should be taken not to exaggerate. A writer varies his tone and his language according to the subject of which be treats, the nature of his literary composition, and the class of readers whom he addresses. Nevertheless an acute and practised mind will have little difficulty in recognizing among the various works of a given author certain qualities which betray at once the character of the writer and his style or habitual manner of writing. Another and a surer means for the detection of positive forgery or the alteration of a document is the commission of anachronisms in facts or dates, the mention in a work of persons, institutions, or customs that are certainly of a later date than the period to which it claims to belong; akin to this are plagiarism and the servile imitation of more recent writers.
The critic must now make the best possible use of the written sources at his disposal, i. e. he must understand them well, which is not always an easy matter. His difficulty may arise from the obscurity of certain words, from their grammatical form, or from their grouping in the phrase he seeks to interpret. As to the sense of the individual words it is supremely important that the critic should be able to read the documents in the language in which they were written rather than in translations. Doubtless there are excellent translations, and they may he very helpful; but it is always dangerous to trust them blindly. The scholar who enters conscientiously upon the work of critic will always feel it a strict duty to warn his readers whenever he quotes a text from a translation. It is well known that to interpret a term correctly it is not enough to know its meaning at a particular epoch, which we are accustomed to regard as classic, in the language to which it belongs. We need only open any large Latin lexicon, e. g. Forcellini's or Freund's (especially if we keep in view the corresponding page of the Latin "Glossarium" of Du Cange), to appreciate at once the very remarkable modifications of meaning undergone by Latin terms in different periods of the language, either from the substitution of new meanings for older ones or by the concurrent use of both old and new. In his efforts to fix the age of a text the critic will, therefore, be occasionally obliged to exclude a meaning that had not yet arisen, or had ceased to be in use when the text in question was composed; sometimes he will be left in a condition of uncertainty or suspense, and obliged to abstain from conclusions agreeable enough but unsafe. Again, in order to grasp correctly the sense of a text it becomes necessary to understand the political or religious opinions of the author, the peculiar institutions of his age and country, the general character of his style, the matters which he treats, and the circumstances under which he speaks. These things considered a general expression may take on quite a particular sense which it would be disastrous for the critic to overlook. Often these details can only be understood from the context of the passage under discussion. In general, whenever there is occasion to verify the exactness of a quotation made in support of a thesis, it is prudent to read the entire chapter whence it is taken, sometimes even to read the whole work. An individual testimony, isolated from all its surroundings in an author's work, seems often quite decisive, yet when we read the work itself our faith in the value of the argument based on such partial quotation is either very much shaken or else disappears entirely.
What is now the value of a text rightly understood? Every historical statement or testimony naturally suggests two questions: Has the witness in question a proper knowledge of the fact concerning which he is called to testify? And if so, is he altogether sincere in his deposition? On an impartial answer to these questions depends the degree of confidence to be accorded to his testimony.
Concerning the knowledge of the witness we may ask: Did he live at the time when, and in the place where, the fact occurred, and was he so circumstanced that he could know it? Or, at least, are we sure that he obtained his information from a good source? The more guarantees he gives in this respect the more, all else being equal, does he prove himself trustworthy. As to the question of sincerity it is not enough to be satisfied that the witness did not wish to utter a deliberate lie; if it could be reasonably shown that he had a personal interest in warping the truth, grave suspicions would be raised as to the veracity of all his statements. Cases of formal and wilful mendacity in historical sources may be regarded as rare. Much more frequently prejudice or passion secretly pervert the natural sincerity of a man who really respects himself and esteems the respect of others. It is possible, and that with a certain good faith, to deceive both one's self and others. It is the duty of the critic to enumerate and weigh all the influences which may have altered more or less the sincerity of a witness -- personal likes or dislikes, social or oratorical proprieties, self-esteem or vanity, as well as the influences which may affect the clearness of a writer's memory or the uprightness of his will. It by no means follows that the authority of a witness is always weakened by the process described above; often quite the contrary happens. When a witness has overcome influences that usually powerfully affect a man's mind and dissuade him from yielding to the natural love of truth, there is no longer any reason to doubt his veracity. Moreover, when he asserts a fact unfavourable to the religious or political cause which he otherwise defends with ardour; when he thus gains no particular advantage, but on the contrary subjects himself to serious disadvantage; in a word, whenever his statements or avowals are in manifest opposition to his interests, his prejudices, and his inclinations, it is clear that his evidence is far weightier than that of a perfectly disinterested man. Again, the preceding considerations apply not only to the immediate witnesses of the fact in question, but also to all the intermediaries through whom their evidence is transmitted to us. The trustworthiness of the latter must be established as well as that of the authorities to which they appeal.