After discussing some implications of early works on international law for libertarian theory, Smith concludes with a defense of Ayn Rand’s theory of rights.

George H. Smith was formerly Senior Research Fellow for the Institute for Humane Studies, a lecturer on American History for Cato Summer Seminars, and Executive Editor of Knowledge Products. Smith’s fourth and most recent book, The System of Liberty, was published by Cambridge University Press in 2013.

In Part 1 of this series, I discussed how many of the works on international law, especially those published during the seventeenth and eighteenth centuries, provided the infrastructure for a libertarian theory of rights. (This was called the “law of nations” in its early stages; the word “international” was coined by Jeremy Bentham in the late eighteenth century.) I do not wish to suggest that all natural‐​law philosophers reached libertarian conclusions. On the contrary, some, such as Samuel Pufendorf and Christian Thomasius, defended a form of political absolutism, whereas others reached more liberal conclusions.

Such differences highlight the fact that philosophers who begin with the same basic premises may develop and apply those premises differently. I will discuss these and other problems in a later series on the natural law/​natural rights tradition, but they are too complex to cover here. (Over forty of the most important works on modern natural‐​law theory have been published by Liberty Fund in a series on Natural Law and Enlightenment Classics. The significance of this ambitious and scholarly project for the history of classical liberal and libertarian thought can scarcely be overestimated.)

I noted in my last essay that philosophers of international law typically based their ideas about the rights of sovereign nation‐​states on the natural rights of sovereign individuals in a state of nature. This analogy is unjustified, in my opinion, since nations should not be viewed as autonomous moral agents. Nevertheless, this methodology, by focusing on the rights of sovereign individuals, yielded a number of significant results, including the following:

(1) International law, by its very nature, must apply to every nation, regardless of the dominant religious beliefs of a particular nation. This requirement led to a greater emphasis on the distinction between natural law and theology, especially divine revelation as it was believed to exist in the Bible. As Hugo Grotius famously remarked in the Prolegomena to The Law of War and Peace (1625):

What we have been saying [about natural law] would have a degree of validity even if we should concede that which cannot be conceded without the utmost wickedness, that there is no God, or that the affairs of men are of no concern to him.

Although many Catholic philosophers prior to Grotius followed Thomas Aquinas in affirming that the precepts of natural law can be known by reason alone, their Protestant counterparts believed that the scholastics had relied too much on revelation in their discussions. Not surprisingly, Protestant philosophers also objected to Catholic efforts to elevate the authority of the pope over secular rulers. This is not to say that Protestant philosophers excluded God from the realm of natural law altogether, but, again, this is a complicated controversy that I cannot discuss here.

The secularization of natural law was inherent in the very nature of international law, since to stress the Bible as a moral authority would not be accepted by non‐​Christian nations. Only an appeal to the principles of reason could lay claim to universal validity among all nations, Christian and non‐​Christian alike. Moreover, the claim that sovereign nation‐​states have equal rights, regardless of their religious affiliations, could only be justified if religious beliefs were irrelevant to the natural rights of individuals in a state of nature. Although it would be wide of the mark to say that Protestant theorists of natural law were always consistent defenders of religious freedom, it is fair to say that most advocated religious toleration.

(2) The primary purpose of theories of international law was to establish universal criteria, based on reason, for a just war. Whereas earlier philosophers had typically used terms like “injury” to specify when a war is justified–a proviso that permitted a broad range of interpretations–natural-rights philosophers insisted that only a violation of rights can justify a war, and that these rights place moral restraints on what belligerents may properly do while fighting a war. As Grotius wrote:

Least of all should that be admitted which some people imagine, that in war all [moral] laws are in abeyance. On the contrary, war ought not to be undertaken except for the enforcement of rights; when once undertaken, it should be carried on only within the bounds of law and good faith. [I]n order that wars may be justified, they must be carried on with no less scrupulousness than judicial processes are wont to be.

According to Grotius, natural rights are violated by physical force, so a nation may go to war with another nation only when its rights have been violated by the use (or threat) of force. The philosophers of international law generally agreed that the internal affairs of a nation are not the concern of other nations–a principle that was intended to lessen the pretexts for war. This reasoning had significant implications when applied to individuals in a state of nature. Sovereign individuals, like sovereign nation‐​states, may use force only in defense of their rights or to rectify a previous injustice. This reasoning entailed a private sphere of activity for individuals in which others may not coercively interfere.

Having discussed some implications of just war theory for libertarianism, I shall now turn to the justification of natural rights. In the natural‐​law tradition that I have been discussing, there were two basic methods of justifying rights, which I shall dub the theological and the secular.

Put in legalistic terms, the theological approach to rights may be summarized as follows: God created human beings, so we are his property. We are all equal in the sense that God did not invest some people with an inherent authority over others. Moreover, God would not have created us without a reason, so we have a duty to preserve our lives. (Suicide was therefore condemned throughout this tradition.) And from this duty of self‐​preservation emerges my natural rights relative to other people. My right to life means that others have a duty not to (say) murder me, because to do so would be to destroy God’s property, in effect.

In this way of thinking (which was defended by John Locke, among others) we may be said to be self‐​owners with moral jurisdiction over our lives, liberty, and property in the context of a human community (though not in relation to God). Such rights were implicit in the very act of creation. The fact that God endowed us with the power of reason and made reason our basic means of survival clearly indicates that he intended us to use our reason to preserve our lives. And since reason is nullified by coercion, persuasion rather than force is the proper way to deal with others.

Thus the theological approach begins with duties, and it generates rights from these duties. From our duty to God to preserve our own lives flows our duty to respect the lives of other people. And from these duties emerge our rights to life, liberty, and property–moral claims that are essential to human life.

The secular approach to rights is a bit more difficult to summarize, but we should not suppose that all defenders of this approach were deists or atheists. Christians sometimes took the secular route in an effort to ground rights more firmly in reason alone. For example, the Swiss philosopher Emer de Vattel (1714–1767), the most popular and influential writer on international law in eighteenth‐​century America, attempted to ground natural rights solely on rational self-interest–or “self‐​love,” as it was commonly called in his day.

In order to understand what was involved here, we need to distinguish a rights‐​claim per se from our obligation to respect such claims. Contrary to those contemporary philosophers who seem to believe that David Hume was the first to appreciate the difference between Is and Ought, or facts and values, the distinction was well understood and thoroughly discussed by natural‐​law philosophers prior to Hume. Although all such philosophers agreed that the principles of natural law, including natural rights, can be discovered by reason, they sometimes disagreed over the source of our obligation to respect those principles. The theological approach, as discussed above, was an effort to ground our obligation to respect the rights of other people in our duty to God.

The secular approach, in contrast, attempted to establish the moral primacy of rights over duties. But even if we agree with the most common secular argument for rights, according to which rights are a necessary condition for the pursuit of happiness in a social context, the question remains: Why should I respect the rights of other people?

As some natural‐​rights philosophers saw the matter, the problem of moral obligation was inextricably linked to human motives. In other words, even if I agree that rights are a social necessity, why should I be motivated to respect the rights of other people in particular cases, especially if I think that my self‐​interest will be served by violating their rights?

Some philosophers, such as Francis Hutcheson and David Hume, attempted to solve this problem by appealing to a “moral sense.” According to this approach, which had variations that I cannot discuss here, humans have an innate sense of right and wrong; and though this capacity does not tell us specifically what is good and what is evil, it does motivate us to pursue the good after reason has identified it.

In contrast to the moral sense school, which tended to identify obligation with a feeling that motivates action, stood the so‐​called rationalist wing of natural‐​law theory, as exemplified in the writings of Samuel Clarke and William Wollaston. (This was the approach that Hume attacked in his famous distinction between Is and Ought.) In this way of thinking, moral obligation is a species of rational obligation. Just as we are rationally obliged to believe a proposition for which sufficient evidence has been provided, so we are morally obliged to observe a principle of action that has been sufficiently justified. The moral, in brief, is simply rational judgment applied to actions instead of to beliefs.

Having discussed some features of the modern tradition of natural law and natural rights, I shall now indicate my own beliefs.

In my last essay I noted my basic agreement with the views of Ayn Rand, especially as expressed in her essays “Man’s Rights,” “Collectivized Rights,” and “The Nature of Government.” I also noted the significant similarities between her ideas and those of some earlier natural‐​rights philosophers–similarities that emerged from parallel reasoning rather than from familiarity with earlier sources. Consider, for example, this passage from “Man’s Rights”:

“Rights” are a moral concept–the concept that provides a logical transition from the principles guiding an individual’s actions to the principles guiding his relationship with others–the concept that preserves and protects individual morality in a social context–the link between the moral code of a man and the legal code of a society, between ethics and politics. Individual rights are the means of subordinating society to moral law.

As Rand put it later in the same essay, “The principle of man’s individual rights represented the extension of morality into the social system–as a limitation on the power of the state, as man’s protection against the brute force of the collective, as the subordination of might to right.”

These passages mesh nicely with the approach to rights that we find in some of the seventeenth‐ and eighteenth‐​century literature on natural rights, especially as defended by Grotius and his followers. Nevertheless, Rand is all‐​too‐​frequently dismissed by academic philosophers, including some libertarians, as little more than a quack. Her arguments, we are told, are silly and not to be taken seriously.

A problem here is that many academic philosophers are woefully ignorant of early works on natural law and natural rights. We are sometimes told, with an air of assurance appropriate to declaring a self‐​evident truth, that only an ignoramus would attempt to ground rights in self‐​interest. Why? Well, one common reason is that the notion of obligation supposedly applies only to other people; we cannot be said to have obligations to ourselves. It seems that early natural‐​rights philosophers did not get this memo, since many of them wrote extensively on “duties” to oneself. This remark by the Scottish philosopher George Turnbull (1740) is fairly typical: “it may very justly be said, that the whole of our duty consists in a well‐​regulated self‐​love, or in the pursuit of our true happiness.”

Although Rand is often portrayed as a philosophic maverick, she actually represents an earlier method of doing philosophy, including moral and political theory. Of course, since she wrote essays rather than technical treatises on these topics, she cannot be said to have justified her approach in detail. But some of Rand’s admirers, such as Tibor Machan, have developed her ideas in depth. (I especially recommend Liberty and Nature: An Aristotelian Defense of Liberal Order, Open Court, 1991, by Douglas B. Rasmussen and Douglas J. Den Uyl.)

It was Ayn Rand who first convinced me of the reasonableness of natural rights; and though I have read extensively in this field for well over four decades–more extensively, I daresay, than any of her libertarian critics–I remain with the lady who brought me to the dance.