Aquinas does not say that compensation is sinful in itself, he merely states that to lend with the expectation of compensation is sinful.
Yet there would be no sin in receiving something of the kind, not as exacting it, nor yet as though it were due on account of some agreement tacit or expressed, but as a gratuity; since, even before lending the money, one could accept a gratuity, nor is one in a worse condition through lending. (Aquinas, 10)
By allowing gratuity Aquinas is explaining in more detail why usury is sinful. To take a gratuity is merely accepting thanks for helping another, whereas usury is taking money from another by using your advantage of wealth over them.
It is sinful to sell a good for more than it is worth. Aquinas states this quite simply; however his meaning is more difficult to grasp. To purchase something, travel a great distance, and then sell it for more than you purchased it is not sinful. It is not sinful because you are charging for your effort in transporting it. However, if one were to purchase something, and then sell it across the street for more than you purchased it for that would be sinful. That act is sinful because the person purchasing for you would instead purchase from the original, cheaper place if they knew of it. So by this tactic one is making a profit due to another’s ignorance, this is clearly a sinful act.
Another manner in which trade could be considered moral is if the profit gained was only enough to support the trader. Aquinas states:
Thus, for instance a man may intend the moderate gain which he seeks to acquire by trading for the upkeep of his household, or for the assistance of the needy: or again, a man may take to trade for some public advantage, for instance, lest his country lack the necessaries of life, and seek gain, not as an end, but as payment for his labor. (Aquinas, 6)
However, in regards to the clergy Aquinas considers trade to by sinful; not because of the act, but because of the possible temptations for sin that trade allows. So Aquinas’ basic view of trade is that one may engage in trade as long as that activity does not harm or take advantage of another.
When selling a good that is defective, or worth less than it actually appears to be worth one must inform the customer. “…if the seller is aware of a fault in the thing he is selling, he is guilty of a fraudulent sale, so that the sale is rendered unlawful.” (Aquinas, 3) Interestingly Aquinas does not believe that a seller must inform his customers in the initial advertisement, as this would scare them off, rather he believes that simply informing them before the sale is complete is enough. “There is no need to publish beforehand by the public crier the defects of the goods one is offering… such defect ought to be stated to each individual who offers to buy.” (Aquinas, 5) This is consistent with his belief that trade in itself is acceptable, but taking advantage of another’s inability to judge a good product is not.
When measuring an amount of material to be sold one must be fair and equitable in the deal. To add false weight or measure incorrectly, and then misrepresent the weight is sinful. “Thou shalt not have divers weights in they bag, a greater and a less: neither shall there be in they house a greater bushel and a less.” (Aquinas, 3) If one misrepresented the amount that the buyer was purchasing one would again be taking advantage of another for personal gain.
As much as Aquinas advocates that people ought not to benefit from the loss of another, he does not advocate the outlawing of usury or regulation of trade. He does this for two reasons; the first is that humanity is imperfect and many will commit the sin of usury and misrepresentation out of a desire for personal gain, the second reason is that usury has its advantage for mankind as a whole. “Wherefore human law has permitted usury, not that it looks upon usury as harmonizing with justice, but lest the advantage of many should be hindered.” (Aquinas, 8) Why usury is too the advantage of many is probably due to the nature of investment capital as being beneficial to the growth of industry and commerce, although these concepts were very poorly understood in the 13th Century. Or Aquinas could simply mean that usury is beneficial to those who partake in it, and those individuals are often men of power and influence who would be loath to allow their lucrative business to come to an end.
Thomas Aquinas’ philosophy is very simple. He believes that everyone should work for the betterment of everyone else, and for their own continued existence. Due to this view he proscribes a view of honesty that forces people into working for the common good. Trading, which inherently divides the population between the haves and the have nots, needs to be controlled for the betterment of all. Aquinas is attempting to civilize and Christianize Europe by putting forth a definition of honesty that makes taking advantage of another sinful. Since misrepresenting a good’s worth is sinful a merchant can’t take an uninformed person’s money. Usury is sinful; therefore making money by using your advantage of money is also impossible. Aquinas seems in many ways to be advocating a type of socialism wherebye everyone is on an equal economic level based on honesty and fairness in business. Taking advantage of another and benefiting by their lack of knowledge or fortune truly is sinful, and Saint Thomas Aquinas can tell you why.
