But in those days the wants of mankind were of a different nature. At present there is a demand for the ingenuity of man; then there was a demand for his person and service. Now provided there be a demand for man, whatever use he be put to, the species will multiply; for those who stand in need of them will always feed them, and as long as food is to be found, numbers will increase.
In the present times food cannot, in general, be found, but by labour, and that cannot be found but to supply wants. Nobody will feed a free man, more than he will feed the wild birds or beasts of the field, unless he has occasion for the labour of the one or the flesh of the other.
In the old world the principles were the same, but the spirit of nations was different. Princes wanted to have numerous armies. Free states sought for power in the number of their citizens. The wants of mankind being few, and a simplicity of manners established, to have encouraged industry, excepting in agriculture, which in all ages has been the foundation of population, would have been an inconsistency. To make mankind labour beyond their wants, to make one part of a state work to maintain the other gratuitously, could only be brought about by slavery, and slavery was therefore introduced universally. Slavery was then as necessary towards multiplication, as it would now be destructive of it. The reason is plain. If mankind be not forced to labour, they will only labour for themselves; and if they have few wants, there will be little labour. But when states come to be formed, and have occasion for idle hands to defend them against the violence of their enemies, food at any rate must be procured for those who do not labour; and as, by the supposition, the wants of the labourers are small, a method must be found to increase their labour above the proportion of their wants.
For this purpose slavery was calculated: it had two excellent effects with respect to population. The first, that, in unpolished nations, living upon the spontaneous fruits of the earth, and almost continually in war, lives were preserved for the sake of making slaves of the captives. These sold to private people, or different states, were sure of being fed; whereas remaining in their own country, they only occupied a place, which, by the force of the generative faculty, as has been observed, was soon to be filled up by propagation: for it must not be forgot, that when numbers are swept off, by any sudden calamity, which does not proportionally diminish subsistence, a new multiplication immediately takes place. Thus we perceive the hurt done by plagues, by war, and by other devastations, either among men, or cattle, repaired in a few years, even in those countries where the standard number of both is seldom found to increase. What immense quantities of cattle are yearly slaughtered! Does any body imagine that if all were allowed to live, numbers would increase in proportion? The same is true of men.
The second advantage of slavery was, that in countries where a good police prevailed, and where the people had fewer wants by far than are felt in modern times, the slaves were forced to labour the soil which fed both them and the idle freemen, as was the case in Sparta; or they filled all the servile places which freemen fill now, and they were likewise employed, as in Greece and in Rome, in supplying with manufactures those whose service was necessary for the state.
Here then was a violent method of making mankind laborious in raising food; and providing this be accomplished, (by any means whatever) numbers will increase.
Trade, industry, and manufactures, only tend to multiply the numbers of men, by encouraging agriculture. If it be therefore supposed, that two states are equally extended, equally fruitful, and equally cultivated, and the produce consumed at home, I believe they will be found equally peopled. But suppose the one laboured by free men, the other by slaves, what difference will be found in making war? In the first, the free hands must, by their industry and labour, purchase their food, and a day lost in labour is in a manner a day of fasting: in the last, the slaves produce the food, they are first fed, and the rest costs nothing to the body of free men, who may be all employed in war, without the smallest prejudice to industry.
From these principles it appears, that slavery in former times had the same effect in peopling the world that trade and industry have now. Men were then forced to labour because they were slaves to others; men are now forced to labour because they are slaves to their own wants.
I only add, that I do not pretend that in fact slavery in antient times did every where contribute to population, any more than I can affirm that the spirit of industry in the Dutch is common to all free nations in our days. All that is necessary for my purpose is, to set forth the two principles, and to shew the natural effects of the one and the other, with respect to the multiplication of mankind and advancement of agriculture, the principal objects of our attention throughout this book.
I shall at present enlarge no farther upon this matter, but return to where I left off in the preceeding chapter, and take up the farther examination of the fundamental distribution of inhabitants into labourers and free hands.