Evolutions: operations involved in the study of them--The place of particular facts (events) in evolution--Important and unimportant facts 244 Periods--How they should be defined 249 CHAPTER III CONSTRUCTIVE REASONING Incompleteness of the facts yielded by documents--Cautions to be observed in filling up the gaps by reasoning 252 The argument from silence--When admissible 254 Positive reasoning based on documents--The general principles employed must enter into details, and the particular facts to which they are applied must not be taken in isolation 256 CHAPTER IV THE CONSTRUCTION OF GENERAL FORMULÆ History, like every science, needs formulæ by which the facts acquired may be condensed into manageable form 262 Descriptive formulæ--Should retain characteristic features--Should be as concrete as possible 264 Formulæ describing general facts--How constructed--Conventional forms and realities--Mode of formulating an evolution 266 Formulæ describing unique facts--Principle of choice--"Character" of persons--Precautions in formulating them--Formulæ describing events 270 Quantitative formulæ--Operations by which they may be obtained: measurement, enumeration, valuation, sampling, generalisation--Precautions to be observed in generalising 274 Formulæ expressing relations--General conclusions--Estimation of the extent and value of the knowledge acquired--Imperfection of data not to be forgotten in construction 279 Groups and their classification 282 The "solidarity" of social phenomena--Necessity of studying causes--Metaphysical hypothesis--Providence--Conception of events as "rational"--The Hegelian "ideas"--The historical "mission"--The theory of the general progress of humanity 285 The conception of society as an organism--The comparative method--Statistics--Causes cannot be investigated directly, as in other sciences--Causation as exhibited in the sequence of particular events 288 The study of the causes of social evolution must look beyond abstractions to the concrete, acting and thinking men--The place of hereditary characteristics in determining evolution 292 CHAPTER V EXPOSITION Former conceptions of history-writing--The ancient and mediæval ideal--The "history of civilisation"--The modern historical "manual"--The romantic ideal at the beginning of the century--History regarded as a branch of literature up to 1850 296