In such discussions, it becomes important to clarify our terms. We must understand both the concept of rights and the concept of nature to which I'm referring. For rights, I've covered that somewhat in my last post. However, to reiterate I quote from the Stanford Encyclopedia of Philosophy which has a fairly good summation on the universality of human rights:
Human rights are universal All living humans—or perhaps all living persons—have human rights. One does not have to be a particular kind of person or a member of some specific nation or religion to have human rights. Included in the idea of universality is some conception of independent existence. People have human rights independently of whether they are found in the practices, morality, or law of their country or culture. This idea of universality needs several qualifications, however. First, some rights, such as the right to vote, are held only by adult citizens or residents and apply only to voting in one's own country. Second, the human right to freedom of movement may be taken away temporarily from a person who is convicted of committing a serious crime. And third, some human rights treaties focus on the rights of vulnerable groups such as minorities, women, indigenous peoples, and children.1When I am discussing nature as the supplier of rights, I'm pointing to the idea that the natural world is all there is; we exist only because of the physical laws of the universe and perhaps some fortuitous chemical combinations and mutations that ultimately resulted in human beings. This concept is well known as metaphysical naturalism or materialism and has many adherents within the scientific community. Those who ascribe to this worldview and still seek to maintain that human rights are real would seek to ground those rights in the natural world instead of God.
But this is where the problem lies. Nature cannot bestow rights at all. The natural world is what we observe. It has materials and laws, such as the laws of gravity or the laws of physics, which describe how certain materials interact. If one drops a cannonball off a ledge, it will fall at a certain acceleration. If one combines an acid and a base, the result will be salt and water (and possibly a big explosion!)
But laws such as these are merely descriptors. They tell what will happen if certain conditions are met. Human rights are something different. For while all living persons have rights, it is not the case that all living persons will be able to exercise those rights. People are denied their rights by dictators or repressive regimes all the time.
That means that nature only provides an "is" description of the way things are while someone being allowed to exercise his or her rights fall into an "ought" description. Rights are things based in the intrinsic value of being human. Nature doesn't care about value, it is indifferent to whether creatures live or die. Species have gone extinct since the dawn of time, even without man's help. Sickness can wipe out entire nations. That is simply how things are. This means that rights are fundamentally different from nature and the description of what is. An "ought" can only be derived from a moral law, which must come from a transcendent mind.
Scottish skeptic David Hume is famous for explaining the is-versus-ought distinction. Hume explains that simply because something is the case, it does not mean that such ought to be. In Book III, Part 1, Section 1 of A Treatise of Human Nature he expounds on this, writing that "moral good and evil belong only to the actions of the mind"2 and therefore cannot be reasonably derived from only external circumstances. He continues, "All beings in the universe, considered in themselves, appear entirely loose and independent of each other. It is only by experience we learn their influence and connection; and this influence we ought never to extend beyond experience… But to choose an instance, still more resembling; I would fain ask any one, why incest in the human species is criminal, and why the very same action, and the same relations in animals have not the smallest moral turpitude and deformity?"3
As Hume has shown, there is no way to connect the "is" of the natural world to the "ought" of human rights. Even if you argue that such rights help human beings survive, who is to say that humans shouldn't go extinct? Nature doesn't care. Therefore, as rights are part of those "actions of the mind" it requires a mind to ground them, and since human rights are universal, that mind must not only transcend all of humanity, but be able to establish value for all of humanity. The Creator of humanity would fill both necessary conditions for universal human rights to exist. Therefore, the Founding Fathers had it right: it is only in our Creator that we are endowed with certain unalienable rights. No other explanation makes sense.
2. Hume, David. "Moral Distinctions Not Derived From Reason." A Treatise of Human Nature, Book II, Part 1,Sect. 1. Project Gutenberg. Web. 10-11-2012. http://www.gutenberg.org/files/4705/4705-h/4705-h.htm#link2H_4_0085 Accessed 7-7-2014.