But how are we to proceed in view of the fact that most researches have been conducted upon methods which, if not defective, are at least open to suspicion? Universal confidence would lead to error as surely as universal distrust would make progress impossible. One useful rule, at any rate, may be stated, as follows: The works of historians should be read with the same critical precautions which are observed in the reading of documents. A natural instinct impels us to look principally for the conclusions, and to accept them as so much established truth; we ought, on the contrary, to be continually applying analysis, we ought to look for the facts, the _proofs_, the fragments of documents--in short, the materials. We shall be doing the author's work over again, but we shall do it very much faster than he did, for that which takes up time is the collection and combination of the materials; and we shall accept no conclusions but those we consider to have been proved. CHAPTER II THE GROUPING OF FACTS I. The prime necessity for the historian, when confronted with the chaos of historical facts, is to limit the field of his researches. In the ocean of universal history what facts is he to choose for collection? Secondly, in the mass of facts so chosen he will have to distinguish between different groups and make subdivisions. Lastly, within each of these subdivisions he will have to arrange the facts one by one. Thus all historical construction should begin with the search for a principle to guide in the selection, the grouping, and the arrangement of facts. This principle may be sought either in the external conditions of the facts or in their intrinsic nature. The simplest and easiest mode of classification is that which is founded on external conditions. Every historical fact belongs to a definite time and a definite place, and relates to a definite man or group of men: a convenient basis is thus afforded for the division and arrangement of facts. We have the history of a period, of a country, of a nation, of a man (biography); the ancient historians and those of the Renaissance used no other type. Within this general scheme the subdivisions are formed on the same principle, and facts are arranged in chronological and geographical order, or according to the groups to which they relate. As to the selection of facts to be arranged in this scheme, for a long time it was made on no fixed principle; historians followed their individual fancy, and chose from among the facts relating to a given period, country, or nation all that they deemed interesting or curious. Livy and Tacitus mingle accounts of floods, epidemics, and the birth of monsters with their narratives of wars and revolutions.