Well, let me tell you where I think the challenge is. And it is a perennial challenge. There is a dominant mode of discourse in every age. In the medieval period, sometimes known as “the age of faith,” the dominant mode of discourse was theological. In the Enlightenment period, sometimes known as “the age of reason” or as “the age of science,” the dominant mode of discourse was rationalist, scientific (or some might say scientististic). Today, the dominant mode of discourse is the discourse of human rights. What we know from historical experiences is that people will articulate or defend their views, make their claims about ethics including the question of justice, in the dominant discourse of the day whatever that discourse happens to be. Whatever people want today when it comes to public policy or cultural norms, they will defend the putative right to it in the language of rights—human rights. So it is incumbent upon us to recognize that, and to identify an intellectually sound way to distinguish valid from invalid claims of human rights. So the first question we have to ask ourselves is this: What is it to claim that something is a human right? It means, at a minimum, that all people are entitled to it simply in virtue of their humanity. In other words, a human right is something that we are entitled to not in virtue of any achievement on our part, not in virtue of any quality or trait that varies from person to person, such as race, sex or ethnicity, intelligence or beauty. Rather, for something to be a human right it must be something to which we are entitled simply in virtue of our humanity. This immediately raises another question. What does it mean to be a human being? We know what it means biologically: it means to be a member of a certain species, Homo sapiens. Do human rights attach to us in virtue of our species membership, or is it something else that makes us human? Aristotle said that our humanity is bound up with our status as rational animals. It is important to understand that this does not mean that only those human beings who have immediately exercisable capacities for self-awareness, deliberation, judgment and choice are to count as true human beings. But it does mean that to be human is to have a human nature. This is something that natural law theorists put a great deal of weight on. What distinguishes us from non-human terrestrial entities, including non-human creatures, is that we are rational animals. Our nature is a rational nature. We are fundamentally organized biologically for self-awareness, deliberation, understanding judgment, choice and related mental activities. We have these capacities in radical (that is, in root) from our very beginning, from the earliest embryonic stage of our existence; and we retain them until our death even if we lose due to dementia or to other cognitive disability the immediately exercisable capacities for characteristically human mental functions. In other words, we have, from the beginning, and retain until death, our human nature. The points I am here making have been developed and defended with great care and depth by natural law theorists from ancient times to the present. Natural-law theorists are fundamentally concerned with human nature and with the goods of human nature and the moral norms that follow as specifications of the rational principle that we should choose and act in ways that are in line with the integral good of human beings.
So is this the reason why the Declaration of Independence of the United States declares that fundamental rights are inalienable?
Yes, that is right. If there are indeed natural rights—human rights—as I believe there are, they are rights that do not come from kings or parliaments. Nor they do come from presidents or courts. We have them in virtue of our humanity. Because they are not gifts of merely human political authorities, no merely human political authority can legitimately violate them or take away. Thomas Jefferson and the Declaration of Independence joined by all the signers, by the American Founders, say that these rights come as “endowments” from “the Creator”—from God, who made human nature just as He made all things. As natural-law theorists often say, if human nature were different, the human good would be different, and human rights (if there were any) would therefore be different. One way of thinking about it is the following. Whether or not there exists a God or a Supreme Being, human beings possess capacities that are traditionally ascribed by religious believers to God or to divinity, namely, freedom of the will and rationality. These are literally God-like powers: freedom and reason. This is the ground of our dignity. And because we have that inherent—and equal—dignity our rights cannot be taken away; nor can they be given away: this is what inalienable (or, to use the spelling in the Declaration of independence, “unalienable”) means.
Natural, or human, rights are ours in virtue of our humanity.
They are not rights others give us, nor are they rights we give ourselves. We are not the authors of our own rights. A power even higher than ourselves endows us with these rights. So we cannot alienate these rights: the right to life, liberty, and the pursuit of happiness, for example. (But please note that it is important to understand “happiness” in the way it was understood by the Founding Fathers, that is as a morally inflected “happiness.” The pursuit of happiness is the pursuit of goodness, of human well-being and fulfillment, the pursuit of blessedness, flourishing.)