Why marginal rate of substitution must to equal the ratio of price of 2 given goods for the consumer to achieve maximum satisfaction?

Norman jones, an economic historian at the university of utah, has described the views of the ancient greek philosopher aristotle on interest: aristotle defined money as a good that was consumed by use. unlike houses and fields, which are not destroyed by use, money must be spent to be used. there- fore, as we cannot rent food, so we cannot rent money. moreover, money does not reproduce. a house or a flock can produce new value by use, so it is not unreasonable to ask for a return on their use. money, being barren, should not, therefore, be expected to produce excess value. thus, interest is unnatural. what did aristotle mean in arguing that money is “barren”? why would money being barren mean that lenders should not charge interest on loans? do you agree with aristotle’s reasoning? briefly explain.