He supports this conclusion by observing that the late resolution of the Quakers in Pennsylvania to set at liberty all their Negro slaves, may satisfy us that their number cannot be very great. Had they made any considerable part of their property, such a resolution could never have been agreeing to. This quotation reveals the weight which Adam Smith assigns to benevolence. Freeing the slaves was certainly a benevolent action but hardly one likely to be undertaken if the price was a personal ruin. (Ronald Coase: Adam Smiths View of Man. http://www.chicagogsb.edu/research/selectedpapers/sp50a.pdf)If the western European succession argued in support of the dominance of wage labor, the overturn seemed to have been the case transversely the ocean. In the plantations, slavery had outdated earlier forms of labor from Brazil to Carolina. Above a decade before writing Wealth of Nations, Smith had himself concluded that repression was the established form of labor in the world, and he estimated that slavery was improbable to disappear for ages to come. Smith did not recur this prophecy at the end of the eighteenth century. In its place, he offered motives for the apparently general ubiquitous partiality for slaves, regardless of their relative inadequacy while compared with freemen. The first was a common psychological human trait, the contentment resultant from dictating another person. This steady, certainly, could not alone elucidate the changeable modes of labor in the Atlantic world. Even as a feature of Europeans in particular, it was not very practical in showing why the same western European employers of labor had gone in contradictory directions, choosing one form of labor in Europe and another in the lowlands of the Americas.Smith also integrated the dread of general insurrection and the trepidation of a great loss of property as motives for not freeing slaves. In political terms, manumissions might deprive a chieftain of some of his subjects.