But how to explain the recent origins of what now looks like a short-lived faith? The designation of the 1940s as the era when contemporary global commitments were born is one version of a larger mistake. The roots of contemporary human rights are not to be found where pundits and professors have longed to find them: neither in Greek philosophy nor monotheistic religion, neither in European natural law nor early modern revolutions, neither in horror against American slavery nor Hitler’s Jew-killing. The temptation to ransack the past for such "sources" says far more about our own time than about the thirty years after World War II, during which human rights were stillborn and then somehow resurrected.
Individual rights can be constitutional rights, such as those liberties granted to American citizens in the U.S. Constitution and its Bill of Rights. In the USA, individual natural rights guaranteed by the U.S. Constitution include personal security, personal liberty, such as the right to practice one's religion and personal property rights.
 David Little, "The Nature and Basis of Human Rights," in Prospects for a Common Morality. Gene Outka, John P. Reeder, eds. (Princeton University Press, 1992). >; See also: James Nickel, "The Existence of Human Rights," in Stanford Encyclopedia of Philosophy. (2012). >.
Bentham broke with this venerable tradition, in which utility and rights were seen as different aspects of the same process, by rejecting the entire scheme of natural rights and by proposing that social utility serve as both the goal and standard of political activity.
Ireton declared that there was no such thing as natural right.
Darwin in The Descent of Man and On the Origin of Species proposes and produces empirical evidence to support the claim that the natural world is based on survival of the fittest through Natural Selection. This suggests that the natural world is entirely amoral and that the only inherent and fundamental – that is, Natural – principle is that of survival. Obviously, Darwin’s work is only theory based on fact and not fact itself. This implies that, just as with a Supreme Being, it is exceedingly difficult to prove that Nature is essentially amoral. However, if one accepts what is currently the most likely explanation of the facts, then it implies that the natural world cannot have conferred any Natural Rights except, arguably, a right to survive. This is arguable because whilst it is true that the natural world enshrines the desire to survive in its structure, it is difficult to claim that the natural world did so based on a moral or ethical valuejudgement. Nature is a only quasiliving organism which, although containing sentient life within it, is not truly sentient itself.
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Thus did Bentham reject the roundabout method of natural rights, according to which the legislator should respect rights as a means to the end of social utility. Rather, the legislator should calculate social utility directly by assessing the impact of a given law on the greatest happiness for the greatest number.
As I said, this was a significant departure from earlier liberal thinking, in which natural rights and social utility were seen as complementary. Bentham severed this friendly relationship by totally rejecting natural rights. If a particular law promotes the greatest happiness for the greatest number, then it is legitimate and proper, regardless of how it might be evaluated from a natural-rights perspective.
"Natural Law and Natural Rights". Anti Essays. 1 Nov. 2017
Indeed, Austin explicitly endorsed the view that it is not necessarily true that the legal validity of a norm depends on whether its content conforms to morality. But while Austin thus denied the Overlap Thesis, he accepted an objectivist moral theory; indeed, Austin inherited his utilitarianism almost wholesale from J.S. Mill and Jeremy Bentham. Here it is worth noting that utilitarians sometimes seem to suggest that they derive their utilitarianism from certain facts about human nature; as Bentham once wrote, "nature has placed mankind under the governance of two sovereign masters, pain and pleasure. It is for them alone to point out what we ought to do, as well as to determine what we shall do. On the one hand the standard of right and wrong, on the other the chain of causes and effects, are fastened to their throne" (Bentham 1948, 1). Thus, a commitment to natural law theory of morality is consistent with the denial of natural law theory of law.