Aquinas does not argue that natural inclinations per se suffice for moral absolutes, but rather that they suffice to make their objects known as self-evidently good for persons. Acting for the contrary of a natural inclination thereby harms persons and is contrary to the Bonum Precept (Good is to be done and pursued; evil is to be avoided). Acting for a self-evident good, however, becomes morally obligatory only when indispensable.