While, as among primitive tribes, men's actions are mainly independentof one another, social forces can scarcely be said to exist: they come intoexistence along with co-operation. The effects which can be achieved onlyby the joint actions of many, we may distinguish as social. At first theseare obviously due to accumulated individual efforts, but as fast as societiesbecome large and highly organized, they acquire such separateness from individualefforts as to give them a character of their own. The network of roads andrailways and telegraph wires -- agencies in the formation of which individuallabours were so merged as to be practically lost -- serve to carry on a sociallife that is no longer thought of as caused by the independent doings ofcitizens. The prices of stocks, the rates of discount, the reported demandfor this or that commodity, and the currents of men and things setting toand from various localities, show us large movements and changes scarcelyat all affected by the lives and deaths and deeds of persons. But these andmultitudinous social activities displayed in the growth of towns, the streamsof traffic in their streets, the daily issue and distribution of newspapers,the delivery of food at people's doors, etc., are unquestionably transformedindividual energies, and have the same source as these energies -- the foodwhich the population consumes. The correlation of the social with the physicalforces through the intermediation of the vital ones, is, however, best shownin the different amounts of activity displayed by the same society accordingas its members are supplied with different amounts of force from the externalworld. A very bad harvest is followed by a diminution of business. Factoriesare worked half-time railway traffic falls; retailers find their sales lessened;and if the scarcity rises to famine, a thinning of the population still morediminishes the industrial vivacity . Conversely, an unusually abundant supplyof food, occurring under conditions not otherwise unfavourable, both excitesthe old producing and distributing agencies and sets up new ones. The surplussocial energy finds vent in speculative enterprises. Labour is expended inopening new channels of communication. There is increased encouragement tothose who furnish the luxuries of life and minister to the aesthetic faculties.
There are more marriages, and a greater rate of increase in population. Thusthe society grows larger, more complex, and more active. When the whole ofthe materials for subsistence are not drawn from the area inhabited, butare partly imported, the people are still supported by certain harvests elsewheregrown at the expense of certain physical forces, and the energies they expendoriginate from them.
If we ask whence come these physical forces, the reply is of course asheretofore -- the Sun's rays. Based as the life of a society is on animaland vegetal products, and dependent as these are on the light and heat ofthe Sun, it follows that the changes wrought by men as socially organized,are effects of forces having a common origin with those which produce allthe other orders of changes we have analyzed. Not only is the energy extendedby the horse harnessed to the plough, and by the labourer guiding it, derivedfrom the same reservoir as is the energy of the cataract and the hurricane;but to this same reservoir are traceable those subtler and more complex manifestationsof energy which humanity, as socially embodied, evolves. The assertion isstartling but it is an unavoidable deduction.
