Aristotle condemns usury because it is the most extreme and dangerous form of chrematistic acquisition, or the art of making money for its own sake.

According to Aristotle, the "necessary" chrematistic economy is licit if the sale of goods is made directly between the producer and buyer at the right price; it does not generate a value-added product.

The scholastics, in addition to condemning commerce on the authority of the patristic texts, condemned it also on the Aristotelean ground that it was a chrematistic art, and this consideration, as we have seen above, enters into Aquinas's article on the subject.

He, doubtless, went on to draw distinctions between the man who steals books to sell them again for mere pecuniary profit (which he would call "chrematistic," or "unnatural," book-stealing), and the man who steals them because he feels that he is their proper and natural possessor.