[527] When you speak of "natural law^a," then the modern man, Western man, immediately thinks of chemical laws, or of laws of subatomic physics. Then if we read books of the past and hear church history, or history of Greek philosophy or of Medieval philosophy, then he finds that the word "natural law" has a quite different meaning. Natural law is the rational

law of the human mind, which is not identical with but made working by the human conscience. The rational principle of the good and the righteous are the principles of the natural law. So please, in order to avoid confusion, avoid the confusion between PHYSICAL law and RATIONAL law. The word "natural law" covers both of them. Ask yourself always: does this man speak about the rational law of ethics, or does he speak about the physical law of physics. The reason why both of these realms have the same name is the Stoic doctrine of the logos^b, meaning the universal creative principle which has the character of the "word," and the "word" grasps, REASONABLY, the structure of reality, according to Greek thinking. So the logos is the power of universal rationality in the world as a whole. We are formed by the logos and therefore we have natural law in the sense of RATIONAL law, of the law of ethics---and also the law of logic belongs to this realm. Then on the other hand, NATURE is formed by the SAME logos which

makes knowledge possible; and this same logos is responsible for the physical laws, for the laws of nature, according to which the structure of reality is kept together. We speak here in this connection about the rational law of ethics^c. And the theory of natural law^d, to which I refer and which plays such an important practical role in our present ethical discussions in this country, is the law of reason with respect to the ethical realm. Now if this definition is understood, then we can ask: how do we become aware of this natural law^e? Classical Roman Catholic theology has distinguished between an immediate awareness of the principles of natural law, which they called syntheresis, in the Middle Ages, a word which is hard to explain---it might be a distorted Greek word.