Nor has it been our intention to add a new item to the abundant literature of what is ordinarily called the "Philosophy of History." Thinkers, for the most part not professed historians, have made history the subject of their meditations; they have sought for its "analogies" and its "laws." Some have supposed themselves to have discovered "the laws which have governed the development of humanity," and thus to have "raised history to the rank of a positive science."[2] These vast abstract constructions inspire with an invincible _a priori_ mistrust, not the general public only, but superior minds as well. Fustel de Coulanges, as his latest biographer tells us, was severe on the Philosophy of History; these systems were as repugnant to him as metaphysics to the positivists. Rightly or wrongly (without doubt wrongly), the Philosophy of History, not having been cultivated exclusively by well-informed, cautious men of vigorous and sound judgment, has fallen into disrepute. The reader will be reassured--or disappointed, as the case may be--to learn that this subject will find no place in the present work.[3] We propose to examine the conditions and the methods, to indicate the character and the limits, of historical knowledge. How do we ascertain, in respect of the past, what part of it it is possible, what part of it it is important, to know? What is a document? How are documents to be treated with a view to historical work? What are historical facts? How are they to be grouped to make history? Whoever occupies himself with history performs, more or less unconsciously, complicated operations of criticism and construction, of analysis and synthesis. But beginners, and the majority of those who have never reflected on the principles of historical methodology, make use, in the performance of these operations, of instinctive methods which, not being, in general, rational methods, do not usually lead to scientific truth. It is, therefore, useful to make known and logically justify the theory of the truly rational methods--a theory which is now settled in some parts, though still incomplete in some points of capital importance. The present "Introduction to the Study of History" is thus intended, not as a summary of ascertained facts or a system of general ideas on universal history, but as an essay on the method of the historical sciences. We proceed to state the reasons why we have thought such a work opportune, and to explain the spirit in which we have undertaken to write it. I