“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.”
These timeless words penned by the Founding Fathers declare a simple, yet profound moral maxim: All humans are equally valuable and ought to be treated as such. This has come to be known as the Principle of Equality (or Equal Treatment).
Almost all societies throughout history have accepted this truth and lived by it. Jeremy Bentham pointed out that any ethical system must begin with the presupposition that “Each to count for one and none for more than one.” We share a strong intuition that all human persons ought to be treated equally, prima facie. Interestingly enough, the pro-slavery South accepted and lived by the Principle of Equality. Even modern-day racists might accept the Principle of Equality as the most basic moral maxim. A racist, however, will seek to redefine the term “human” or “person” to exclude a group of people that he deems unworthy of rights or value. Hence, the racist can happily affirm that all people are equal and ought to be treated equally, and yet disagree on who to include in the category of “people.”
Most rational people today will recognize that racism is wrong—it is evil. However, the problem arises when we seek to ground the Principle of Equality. Why is it that all people are equal? Why is it that all people are born with unalienable rights? Why is it that all people are inherently valuable as ends in and of themselves? In other words, what makes the Principle of Equality really true rather than merely a clever and effective tool to keep society in check?
As it turns out, answering this question is not as easy as it might seem. The French philosopher Jacques Maritain, who helped draft the United Nations Declaration of Human Rights, said, “We agree on these rights, providing we are not asked why. With the ‘why,’ the dispute begins.” Our task is to figure out some common property or set of properties that all human beings share that can bear the weight of substantiating the intrinsic value of the human person. Some potential candidates for grounding human worth and equality might be rationality, intellect, or our capacity for moral reflection and deliberation. Peter Singer argues that all three of these fail. With regard to rationality and intellect, “we can have no absolute guarantee that these abilities and capacities really are evenly distributed evenly, without regard to race or sex, among human beings.” In other words, it's implausible that all humans have the same intellectual capacity; many people are born with severe mental handicaps. Does their diminished ability to function make them less human? Of course not. Does their inability make them less valuable? Of course not. Singer goes on to say, “it is quite clear that the claim to equality does not depend on intelligence, moral capacity, physical strength, or similar matters of facts.” The facts of human intellectual ability, moral capacity, strength, and the like cannot serve as the basis for human value for two reasons:
These abilities are not evenly distributed among all people. Some people are strong, some are weak. Some people are bright, others are not.
It is not clear what it is about these properties that makes them the grounds for inherent human worth. There is nothing in the human capacity for rational reflection that explicitly bespeaks the intrinsic worth of every human being and can serve as its ontological grounds.
Singer finally concludes his argument with a profound point and a concession, “There is no compelling reason for assuming that a factual difference in ability between two people justifies any difference in the amount of consideration we give to satisfying their needs and interests. The principle of equality of human beings is not a description of an alleged equality among human beings: it is a prescription of how we should treat human beings.” Singer looks at the different attempts to ground human worth and finds them all lacking. He concedes that there is no description of humanity that justifies or substantiates the principle of equality, and yet we still ought to treat humans as if we are all equal. For Singer, the Principle of Equality has no basis in reality, but it is a useful fiction and we should still aim to live by it.
The theist can argue that human persons all possess the Imago Dei—the Image of God. God has created all people in such a way that we all carry and reflect the image of the Creator of the cosmos.
Singer's candid concession is honest and laudable, for on his naturalistic position, there is no such property or set of properties that seems likely to bear the weight of Singer's challenge. What could serve as the foundation for intrinsic human value? It is at this point that the theist has the advantage. The theist can take any number of viable approaches in answering this question. The theist can argue that human persons all possess the Imago Dei—the Image of God. God has created all people in such a way that we all carry and reflect the image of the Creator of the cosmos. Every person from the weakest to the strongest—from the least-known to the best-known—has this property. We carry the Image of God. The theist can also ground human value in God's intentions for humanity. God has created human beings with certain ends in mind so that any disruption of those intentions is a disruption of the way God made humans and intended for us to interact. These two options, moreover, are not mutually exclusive by any means. Theists can happily affirm both of these options in answering Singer's challenge. God, as both our Source and End, having created us and imbued us with our telos, provides the robust ontological foundation for intrinsic human worth and moral standing. These approaches take the burden off various human capacities; even when human beings suffer handicaps or lack certain faculties, their ontological status has not diminished one iota. On this view, God has created all people as inherently valuable. All people regardless of race, sex, age, ability to function, sexual orientation, or location are ends in and of themselves—priceless, precious, and loved by God.
While the naturalist can see the need for grounding the Principle of Equality, the theist can offer a viable set of solutions. A Principle of Equality that hangs suspended in mid-air is both ineffective and dangerous. A robust understanding of what ties us all together and validates the notion that all humans are intrinsically valuable is vitally important, now more than ever. It would seem that theism offers a fuller account of the descriptive and prescriptive components of the Principle of Equality than does naturalism.
For further reading on this important issue, including a systematic critique of various secular efforts to ground moral standing and intrinsic human worth, see Mark Linville’s “Moral Argument” available online here: https://appearedtoblogly.files.wordpress.com/2011/05/linville-mark-22the-moral-argument22.pdf
 James Rachels, The Elements of Moral Philosophy (2015), p. 79-80
 Jacques Maritain, Man and the State (1951), p. 77
 Peter Singer, Animal Liberation (1975), p. 4
 Singer, p. 4
 Singer, p. 5
Image:"Scaffolding & First Amendment Of The Constitution Of The United States Of America, Pennsylvania Avenue, NW (Washington, DC)" by takomabibelot. CC License.