Professor Lester F. Ward (Brown University):[340] “Still, the world has never reached a stage where the physical and temporal interests have not been largely in the ascendant, and it is these upon which the economists have established their science. _Self-preservation has always been the first law of nature_ and that which best insures this is the greatest gain.... _All considerations of pride or self-respect will give way to the imperious law of the greatest gain for the least effort._ All notions of justice which would prompt the giving of an equivalent _vanish_ before it....” Thus wrote Sir Henry Maine:[341] “The simple wish to use the bodily powers of another person, as a means of ministering to one’s own ease or pleasure, is doubtless the foundation of slavery.” And thus Professor W. G. Sumner (Yale University):[342] “The desire to get ease or other good by the labor of another and the incidental gratification to vanity seem to be the fundamental principles of slavery, when philosophically regarded, after the rule of one man over others has become established.... It appears that slavery began historically with the war captive, if he or she was not put to death, as he was liable to be by the laws of war.... It seems to be established that it [slavery] began where the economic system was such that there was gain in making a slave of a war captive, instead of killing him.... The defeated [in war] were forced to it [slavery] and _learned to submit to it_.... It seemed to be good fun, as well as wise policy, to make the members of a rival out-group do these tasks, after defeating them in war.... Inasmuch as slavery springs from greed and vanity, it appeals to primary motives and is at once entwined with selfishness and other fundamental vices.... _It rises to an interest which overrules everything else_.... The motive of slavery is base and cruel from the beginning.... The _interests_ normally control life.... Slavery is an instinct which is sure to break over all restraints and correctives.... It is a kind of _pitfall for civilization_.” Here are a few lines from Professors Ely and Wicker (University of Wisconsin, Department of Economics):[343] “It follows from the need of larger territories [in the hunting stage] that war becomes an economic necessity wherever there is not an abundance of unoccupied land. This same condition of things gives us one of the causes of cannibalism. The pressure of increasing numbers bringing people continually to the verge of starvation, they fall, little by little, into the custom of eating enemies, taken in war.... Captives later came to be recognized as of use in serving their captors, and thus slavery succeeds cannibalism....