Briefly, Jan, The Natural (moral) Law holds that all rational human beings have a a capacity to correctly discern what is the right (good) thing to do and what is the wrong (bad) things to do in any moral situation with which they are confronted. The thesis of The Natural Law holds that in any moral situation there is , in fact, always A right thing and A wrong thing to do. Moreover, moral values and duties that are right exist as real objective things that have been determined and ordained a supernatural/transcendent Divine entity. In the case the Christianity, for example, a Christian believes that the Divine Commandments are objective and absolute truths which where DETERMINED and then revealed to mankind by the Biblical God in Scripture, for instance. But the theory of The Natural Law argues that even if one has never read the Bible or been exposed to any Christian moral teachings, or any of the moral teachings of any other religion or culture, provided one is an adult of sound mind, knowledge of what is truly right and what is truly wrong is discernable by any man or woman simply through their inherent ability to reason ( to engage in rational reflection) . For instance, The Natural Law maintains that men and women know for a fact that it is always wrong to lie, to steal, to murder, to break promises , for example, and that if we look back at human history over the millenia it is clear that this is the case. The theory of The Natural (moral) Law hold this is so, NOT because men and women have read this in any sacred religious text or been instructed so by any human expert/authority in the field of morality, like, say, a famed philosopher of ethics, but because ( again, to cite a Biblical reference, this time, St Paul) the truth of what is right and what is wrong exists ( and it exists as an objective, absolute reality) that has been "inscribed on the hearts" of ALL men and women by their Divine Creator.