Risk of Production, Circulation, and Exchange
There is much uncertainty in any act of production: the farmer sows his crop with some sense of the amount that will be produced, but much depends on weather. He does not know how much wheat others are farming, and whether there will be a bounty or scarcity in the market when he harvests. Nor can he forecast the number of births and deaths in the state, the increase or reduction in he income of others, and many other factors that will influence the profit his work will bring.
Likewise, the conveyors of goods from village to city depend on their ability to sell the goods to cover their expenses and costs of carriage to leave them a profit, uncertain of the daily fluctuations of the price of produce in the city. Unless the article can be warehoused over a long period of time (such as wine), there is little opportunity to stockpile for times of increased demand or wait for the price to rise - crops must be sold, and consumed, before they rot.
The craftsmen in town likewise have risk of continuity of supply - a baker without wheat, a butcher without livestock, a tanner without leather, or a weaver without wool is idle and without means of sustenance. They have only limited ability to stockpile materials and goods against the uncertainty of supply. And likewise, they do not know with certainty the price for which they will be able to sell their goods once they are finished, yet must pay a definite price for materials.
Shopkeepers and traders likewise purchase inventory with uncertainty of the price at which they will be able to resell goods. Indeed, the security in possession of any material good, even gold or silver, is at a greater risk than the possession of land.
Ultimately, all members of society are producers of some good or service which they trade for the goods or services of others, and whose dedication to learning the skills of a profession in youth are undertaken with the uncertainty that it will sustain them through the remainder of their lifetime.
The whole of the market is thus interlinked, and even seeking to maintain a delicate balance - the ruin and bankruptcy of men being the consequence of failure to predict the future.
Some distinction is made between the undertaker of a trade and the workers in his hire - especially in that workers are assured of their wages by their agreement to perform certain tasks, whereas the profit of the undertaker is at constant risk. By this reckoning, even beggars and thieves are undertakers.
There is brief mention of the "proprietors of money" who lend to producers at interest. By capitalizing on the proceeds of a great number and diversity of pursuits men of this profession undertake considerable risk and generate great wealth.
All things considered, the author lays down as principle that the proprietors of land alone are "naturally independent" in a state, and capable of sustaining themselves by the produce of their land, with the cooperation of none other. It is only when they seek to produce beyond their means that the excess is traded to others, and this is a matter of convenience rather than necessity.