Natural Law
This is perhaps the Central Theme of the Enlightenment. Man is endowed with Rights, inherently, not granted by human power.
it was the fact that life, liberty, and property existed beforehand that caused men to make laws in the first place. ~Frederic Bastiat
Life, Liberty, and Property. These are the Basic Rights of Man, summarized by the Enlightenment.
We hold these truths to be self-evident: that all men are created equal; that they are endowed by their Creator with certain unalienable rights.. ~Thomas Jefferson
Natural law is the basis for almost all human rights declarations, since the 18th century. From wiki:
..natural law has been claimed or attributed as a key component in the United States Declaration of Independence (1776), the Declaration of the Rights of Man and of the Citizen (1789) of France, the Universal Declaration of Human Rights (1948..)of the United Nations General Assembly, as well as the European Convention on Human Rights (1953) of the European Union.
It is the basis for almost all perceptions of human rights, in contemporary culture. It is not always credited with the ASSUMPTION of human rights, but it is always there.
Again from wiki:
Natural law (Latin: ius natural, lex naturalis) is a philosophy asserting that certain rights are inherent by virtue of human nature, endowed by nature—traditionally by God or a transcendent source—and that these can be understood universally through human reason. As determined by nature, the law of nature is implied to be objective and universal;[1] it exists independently of human understanding, and of the positive law of a given state, political order, legislature or society at large.
Historically, natural law refers to the use of reason to analyze human nature to deduce binding rules of moral behavior from nature's or God's creation of reality and mankind. The concept of natural law was documented in ancient Greek philosophy, including Aristotle,[2] and was referred to in Roman philosophy by Cicero. References to natural law are also found in the Old and New Testaments of the Bible, later expounded upon in the Middle Ages by Christian philosophers such as Albert the Great and Thomas Aquinas.
Natural law is an extrapolation of universal morality:
IF... God or some Creative Power has imbued morality into mankind, as evidenced by the universal acceptance of conscience, THEN.. it follows that this same endowment would include rights, as well as obligations. If murder is 'wrong', then each person has a 'right' to life. If property is a 'right', then theft is 'wrong!'. Morality and natural law are 2 sides of the same coin.
But both morality and natural law are contingent on an Embuing Power. A godless universe has no such power, but only human law and animal instinct. Morality and natural law are human constructs, for manipulation, in a godless universe.
In a godless universe, there is nothing inherently 'wrong!' about murder, or theft, or exploiting anyone.. there are only human laws for those things, passed to manipulate people.
Theft, murder, rape, and exploitation are virtues, in the natural world, and enhance survival. They are also common to man, especially in a lawless, chaotic society.