temporary character of causality; that is to say: If such a phenomenon is produced under such conditions, such another phenomenon will follow. No law placed outside the phenomena: each phenomenon governs that which follows it—not law.
Nothing preconceived in what we call harmony in Nature. The chance of collisions and encounters has sufficed to establish it. Such a phenomenon will last for centuries because the adaptation, the equilibrium it represents has taken centuries to be established; while such another will last but an instant if that form of momentary equlibrium was born in an instant. If the planets of our solar system do not collide with one another and do not destroy one another every day. if they last millions of years, it is because they represent an equilibrium that has taken millions of centuries to establish as a resultant of millions of blind forces. If continents are not continually destroyed by volcanic shocks, it is because they have taken thousands and thousands of centuries to build up, molecule by molecule, and to take their present shape. But lightning will only last an instant: because it represents a momentary rupture of the equilibrium, a sudden redistribution of force.
Harmony thus appears as a temporary adjustment, established among all forces acting upon a given spot—a provisory adaptation; and that adjustment will only last under one condition: that of being continually modified; of representing every moment the resultant of all conflicting actions. Let but one of those forces be hampered in its action for some time and harmony disappears. Force will accumulate, its effect; it must come to light, it must exercise its action, and if other forces hinder its manifestation it will not be annihilated by that, but will end by upsetting the present adjustment, by destroying harmony, in order to find a new form of equilibrium and to work to form a new adaptation. Such is the eruption of a volcano, whose imprisoned force ends by breaking the petrified lavas which hindered them to pour forth the gases, the molten lavas, and the incandescent ashes. Such, also, are the revolutions of mankind.
An analogous transformation is being produced at the same time in the sciences that treat of man. Thus we see that history, after having been the history of kingdoms, tends to become the history of nations and then the study of individuals. The historian wants to know how the members, of which such a nation was composed, lived at such a time, what their beliefs were, their means of existence, what ideal of society was visible to them, and what means they possessed to march towards this ideal. And by the action of all those forces, formerly neglected, he interprets the great historical phenomena.