Then, over and above the special histories in which the facts are arranged under purely abstract categories (art, religion, private life, political institutions), we shall have constructed a concrete general history, which will connect together the various special histories by exhibiting the main stream of evolution which has dominated all the special evolutions. None of the species of facts which we study apart (religion, art, law, constitutions) forms a closed world within which evolution takes place in obedience to a kind of internal impulse, as specialists are prone to imagine. The evolution of a usage or of an institution (language, religion, church, state) is only a metaphor; a usage is an abstraction, abstractions do not evolve; it is only existences that evolve, in the strict sense of the word.[196] When a change takes place in a usage, this means that the men who practise it have changed. Now, men are not built in water-tight compartments (religious, juridical, economic) within which phenomena can occur in isolation; an event which modifies the condition of a man changes his habits in a great variety of respects. The invasion of the Barbarians influenced alike language, private life, and political institutions. We cannot, therefore, understand evolution by confining ourselves to a special branch of history; the specialist, even for the purpose of writing the complete history of his own branch, must look beyond the confines of his own subject into the field of general events. It is the merit of Taine to have asserted, with reference to English literature, that literary evolution depends, not on literary events, but on facts of a general character.
The general history of individual facts was developed before the special histories. It contains the residue of facts which have not found a place in the special histories, and has been reduced in extent by the formation and detachment of special branches. As general facts are principally of a political nature, and as it is more difficult to organise these into a special branch, general history has in practice been confounded with political history (Staatengeschichte).[197] Thus political historians have been led to make themselves the champions of general history, and to retain in their constructions all the general facts (migrations of peoples, religious reforms, inventions, and discoveries) necessary for the understanding of political evolution.
In order to construct general history it is necessary to look for all the facts which, because they have produced changes, can explain either the state of a society or one of its evolutions. We must search for them among all classes of facts, displacements of population, artistic, scientific, religious, technical innovations, changes in the personnel of government, revolutions, wars, discoveries of countries.
That which is important is that the fact should have had a decisive influence. We must therefore resist the natural temptation to divide facts into great and small. It goes against the grain to admit that great effects may have had small causes, that Cleopatra's nose may have made a difference to the Roman Empire. This repugnance is of a metaphysical order; it springs from a preconceived opinion on the government of the world. In all the sciences which deal with an evolution we find individual facts which serve as starting-points for series of vast transformations. A drove of horses brought by the Spanish has stocked the whole of South America. In a flood a branch of a tree may dam a current and transform the aspect of a valley.
In human evolution we meet with great transformations which have no intelligible cause beyond an individual accident.[198] In the sixteenth century England changed its religion three times on the death of a sovereign (Henry VIII., Edward VI., Mary). Importance not to be measured by the initial fact, but by the facts which resulted from it. We must not, therefore, deny a priori the action of individuals and discard individual facts. We must examine whether a given individual was in a position to make his influence strongly felt. There are two cases in which we may assume that he was: (1) when his action served as an example to a mass of men and created a tradition, a case frequent in art, science, religion, and technical matters; (2) when he had power to issue commands and direct the actions of a mass of men, as is the case with the heads of a state, an army, or a church. The episodes in a man's life may thus become important facts.
Accordingly, in the scheme of historical classification a place should be assigned for persons and events.
VI. In every study of successive facts it is necessary to provide a number of halting-places, to distinguish beginnings and ends, in order that chronological divisions may be made in the enormous mass of facts. These divisions are periods; the use of them is as old as history. We need them, not only in general history, but in the special branches of history as well, whenever we study an extent of time long enough for an evolution to be sensible. It is by means of events that we fix their limits.
In the special branches of history, after having decided what changes of habits are to be considered as reaching deepest, we adopt them as marking dates in the evolution; we then inquire what event produced them. The event which led to the formation or the change of a habit becomes the beginning or the end of a period. Sometimes these boundary events are of the same species as the facts whose evolution we are studying—literary facts in the history of literature, political facts in political history. But more often they belong to a different species, and the special historian is obliged to borrow them from general history.
In general history the periods should be divided according to the evolution of several species of phenomena; we look for events which mark an epoch simultaneously in several branches (the Invasion of the Barbarians, the Reformation, the French Revolution). We may thus construct periods which are common to several branches of evolution, whose beginning and whose end are each marked by a single event. It is thus that the traditional division of universal history into periods has been effected. The sub-periods are obtained by the same process, by taking for limits events which have produced consequences of secondary importance.
The periods which are thus constructed according to the events are of unequal duration. We must not be troubled by this want of symmetry; a period ought not to be a fixed number of years, but the time occupied by a distinct phase of evolution. Now, evolution is not a regular movement; sometimes a long series of years passes without notable change, then come moments of rapid transformation. On this difference Saint-Simon has founded a distinction between organic periods (of slow change) and critical periods (of rapid change).