THE DIRECTION OF MOTION. 253 



the support of themselves and families. Hence, the rapid 

 increase of number which occurs in such places, is really a 

 social growth at points where the opposing forces are the 

 least. 



Nor is the law less clearly to be traced in those functional 

 changes daily going on. The flow of capital into businesses 

 yielding the largest returns; the buying in the cheapest 

 market and selling in the dearest; the introduction of more 

 economical modes of manufacture; the development of bet- 

 ter agencies for distribution; and all those variations in the 

 currents of trade that are noted in our newspapers and tele- 

 grams from hour to hour ; exhibit movement taking place in 

 directions where it is met by the smallest total of opposing 

 forces. For if we analyze each of these changes if instead 

 of interest on capital we read surplus of products which re- 

 mains after maintenance of labourers; if we so interpret 

 large interest or large surplus to imply labour expended with 

 the greatest results; and if labour expended with the great- 

 est results means muscular action so directed as to evade ob- 

 stacles as far as possible; we see that all these commercial 

 phenomena are complicated motions set up along lines of 

 least resistance. 



Objections of two opposite kinds will perhaps be made to 

 these sociological applications of the law. By some it may 

 be said that the term force as here used, is used metaphori- 

 cally that to speak of men as impelled in certain directions 

 by certain desires, is a figure of speech and not the statement 

 of a physical fact. 'The reply is, that the foregoing illustra- 

 tions are to be interpreted literally, and that the processes 

 described are physical ones. The pressure of hunger is an 

 actual force a sensation implying some state of nervous 

 tension; and the muscular action which the sensation 

 prompts is really a discharge of it in the shape of bodily mo- 

 tion a discharge which, on analyzing the mental acts in- 

 volved, will be found to follow lines of least resistance. 

 Hence the motions of a society whose members are impelled 



