The fundamental structure of society and the basic principles of human conduct arise from the eternal law, which is the divine reason as it governs the entire universe (L 6). The eternal law is called natural law or natural right (L 6) in view of man's participation in it, as it has been impressed upon the hearts of all men (Rom. 2:14-15). Natural right is engraved in human nature (PT 63); it contains the dictates of man's reason which command him to do what is by nature good for him and prohibit him from doing what is bad. Although the terms are often used synonymously, "natural right" is that part of natural law which refers to human relationships.  (From THE PRINCIPLES OF THE SOCIAL DOCTRINE OF THE CHURCH.)

Human nature is intrinsically good, although it has been corrupted by sin.

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Catholics hold that humans have an innate sense of what is right and what is wrong, called natural law, written into the core of their being. Natural law transcends society and culture; social norms help humans understand what is acceptable in a given society, but natural law gives them a clear knowledge of good and evil. According to St. Thomas Aquinas, natural law allows humans to act in a moral manner, prompting them to choose the greater good of obedience to God rather than the lesser good of following their own desires.  (Roman Catholicism Human Nature and the Purpose of Existence;


The Bible abounds with statements about the natural condition of man - there is no goodness in him. The following is but a small sampling:

But we are all as an unclean thing, and all our righteousnesses are as filthy rags . . .Isa. 64:6 (first part.)  This text applies particularly to the converted, which is why the Remnant of God need cleansing in the Final Atonement - (Cf. Paul's Illustration of Righteousness by Faith; Joshua and the Angel)

For my people is foolish, they have not known me; they are sottish children, and they have none understanding: they are wise to do evil, but to do good they have no knowledge. Jer. 4:22

Yea, the stork in the heaven knoweth her appointed times; and the turtle and the crane and the swallow observe the time of their coming; but my people know not the judgment of the LORD. Jer. 8:7

O LORD, I know that the way of man is not in himself: it is not in man that walketh to direct his steps. Jer. 10:23

The heart is deceitful above all things, and desperately wicked: who can know it? I the LORD search the heart, I try the reins, even to give every man according to his ways, and according to the fruit of his doings Jer. 17:9-10.

For from within, out of the heart of men, proceed evil thoughts, adulteries, fornications, murders, Thefts, covetousness, wickedness, deceit, lasciviousness, an evil eye, blasphemy, pride, foolishness: All these evil things come from within, and defile the man. Mark 7:21-23