Smith explores two concepts of political philosophy and their respective ideas about justice and a good society.

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.

Political philosophy is a systematic inquiry into the nature of a good society, its preconditions, implications, and corollaries. The political philosopher, in framing his conception of a good society, must engage in two kinds of investigation: normative (or prescriptive) and positive (or descriptive). The normative part of political philosophy is concerned with the nature of justice, whereas the positive part is concerned with the nature of social order. What is justice? What is social order? These fundamental questions, when considered in tandem, establish the field of inquiry for that discipline known as political philosophy. (Another descriptive feature of political philosophy is its theory of human nature, which is the ultimate foundation for everything else. I shall discuss this issue later in this series.)

We sometimes think of political philosophy as essentially prescriptive while neglecting its descriptive features. This is an understandable oversight, for justice has traditionally been regarded as the core concept of this discipline. But no theory of justice can be (or ever has been) defended without a corresponding theory of social order. This latter may be tacitly assumed or implicitly contained within a theory of justice, but it is there nonetheless. A philosopher may be unaware of these descriptive elements, he may not have clearly formulated his theory of social order or worked out its implications, but he cannot avoid the fact that justice is a social concept. A theory of justice expresses an ideal relationship—i.e., a relationship that ought to exist—between two or more individuals. We can act unjustly only toward others, never toward ourselves.

Thus, in formulating a theory of justice, the philosopher must consider what would probably happen if his moral ideal were accepted and acted upon in the real world. Would his ideal of justice promote cooperation or conflict, harmony or chaos, abundance or poverty, happiness or misery? No philosopher, of course, will endorse the negative side of these dichotomies. No philosopher will claim that his theory of justice, if implemented, would result in perpetual conflict, chaos, poverty, or misery. We may therefore ask the philosopher how he knows all this. On what basis does he presume that his theory of justice is at least consistent with a minimal degree of social order—that it would not, for example, plunge society into that Hobbesian nightmare, that state of perpetual war of every man against every man where life is “nasty, brutish, and short”?

It is when answering such questions that the political philosopher must rely upon a theory of social order. And this is where the philosopher must venture beyond his native domain of ethics into the foreign territories of sociology, economics, social psychology, and other human sciences.

Political philosophies may be divided into two broad categories, or ideal types. The first assigns to political theory the limited task of determining those general conditions that are necessary for a good society. The second assigns to political theory the more expansive task of determining, not only those conditions that are necessary for a good society, but those that are sufficient as well.

By “necessary” I mean those conditions without which a good society cannot exist. Such conditions are essential but minimal; they establish general principles of justice and social order without prescribing in detail how these principles should be implemented in particular cases. Political philosophy, thus conceived, can lay down general rules while leaving considerable room for social and cultural variations, the specifics of which will often depend on historical circumstances that are unique to a given society.

By “sufficient” I mean those conditions that will result in the best of all possible societies. In contrast to a theory of necessary conditions, which specifies the preconditions of a good society, a theory of sufficient conditions attempts to draft a social blueprint, in effect, often in considerable detail. Or, to use more familiar terms, a theory of sufficient conditions is a theory of social planning.

A theory of necessary conditions will tend to generate a model of the open society, whereas a theory of necessary and sufficient conditions will tend to generate a model of the closed society. These conflicting models result from the inner logic of ideas. To offer a sketch of what is minimally necessary for a good society is to leave considerable room for diversity, variation, and change. But the available space for individuality will progressively decrease as additional details transform what had been a sketch into a veritable blueprint for the good society.

To enumerate the particular details—the sufficient conditions—of a good society is effectively to prohibit individuality and social change. A planned society, a society in which sufficient conditions are politically determined and coercively imposed, is “closed” to the spontaneous innovations of free association. We see this in the utopian writings of Plato and his many admirers. A utopian society is a perfect society, one that has been carefully designed by a wise and beneficent lawgiver. Any deviation from perfection must necessarily be for the worse, so social change—which in this scheme is but another name for social degeneration—must be arrested at all costs. And this, in turn, requires the suppression of individuality. The individual’s pursuit of happiness—that powerful and unpredictable agent of social change—must be subordinated for the sake of a good society, as specified in the utopian blueprint of sufficient conditions.

The difference between these models of political philosophy is reflected historically in two different meanings of the word “political.” The Greek polis, from which our word “political” is derived, referred to many aspects of the ancient Greek city‐​state in addition to its government – to its religious, familial, and educational institutions, for example. Most Greek philosophers, most notably Aristotle, did not distinguish between the political and the social but used “political” to denote all kinds of institutions, whether coercive or voluntary. Thus, where Aristotle said that man is naturally a “political animal,” later Aristotelians would sometimes substitute “social animal” or “social and political animal.”

The older, more expansive meaning of “political,” which included every kind of institution, tended to generate a theory of sufficient conditions. Over time, however, philosophers began to distinguish the political sphere of governmental coercion from the social sphere of voluntary interaction. (For additional details, see my previous essays on State and Society.) It was during this development that philosophers adopted a more restrictive view of political philosophy as a theory of necessary conditions for a good society. The political sphere of coercion was now set apart from the social sphere of voluntary association, and it became a major task of political philosophy to establish a bright line between these two spheres. This was the perspective adopted by classical liberals. They agreed with John Milton’s comment in Areopagitica (1644): “here the great art lies, to discern in what the law is to bid restraint and punishment, and in what things persuasion only is to work.”

According to classical liberals, a theory of justice should define and delimit the proper sphere of government—the realm of legitimate coercion, in contradistinction to the social realm of voluntary interaction. A government should concern itself only with matters of justice, while leaving individuals free to pursue their own values in religious, economic and personal affairs. This meant that the primary task of political philosophy, strictly speaking, is to determine the nature of a just society rather than a good society per se.

Adam Smith clearly expressed this distinction in The Theory of Moral Sentiments (1759; 6th ed., 1790), where he discussed “that remarkable distinction between justice and all the other social virtues.” The obligations of justice “may be extorted by force,” whereas the social virtues of beneficence—those affiliated with friendship, charity, generosity, and the like—should depend solely on “advice and persuasion.” Indeed, “for equals to use force against one another” in an effort to compel the observance of social virtues other than justice “would be thought the highest degree of insolence and presumption.”

Justice, according to Smith, is necessary for the very existence of society. Even if people interacted for no reason other than personal gain, narrowly conceived, a society that enforces the rules of justice could function satisfactorily. But a just society is not necessarily the best possible society. The moral quality of a just society will depend on the voluntary social virtues (which Smith subsumed under the label “beneficence”) practiced by its members.

Society may subsist among different men, as among different merchants, from a sense of its utility, without any mutual love or affection; and though no man in it should owe any obligation [apart from justice], or be bound in gratitude to any other, it may still be upheld by a mercenary exchange of good offices according to an agreed valuation.

…Society may subsist, though not in the most comfortable state, without beneficence; but the prevalence of injustice must utterly destroy it…. [Beneficence] is the ornament which embellishes, not the foundation which supports the building, and which it was, therefore, sufficient to recommend, but by no means necessary to impose. Justice, on the contrary, is the main pillar that upholds the whole edifice. If it is removed, the great, the immense fabric of human society…must in a moment crumble into atoms.

From this libertarian perspective, political philosophy is concerned with the nature of a good society only insofar as it establishes conditions that are necessary, but not sufficient, for a good society. Political philosophy addresses the nature of a just society; whether the members of that society practice other moral virtues that render the society good rather than merely tolerable will depend on their voluntary decisions and actions. Those issues fall within the purview of ethics in the broadest sense; they are not matters of political philosophy per se.

Having laid this groundwork, I will now address an obvious and common objection to the libertarian conception of a just society: How can justice be maintained in a society if most of its members lack the social virtues essential to a free society? If, for example, most people are looking for any opportunity to cheat or rob others, and are restrained only by the fear of legal punishment, then the foundation of social order will be precarious indeed. If we are free to make our own decisions in pursuit of our own interests (so long as we respect the equal rights of others), then why would we ever respect the moral autonomy of others—their rights—except incidentally, as when we deem voluntary interaction conducive to our own ends or when we fear the legal consequences of aggression? Even if, as Adam Smith argued, a just society could exist without the social virtues of beneficence, what kind of society would it be? Would any reasonable person really want to live in that kind of society?

Problems like these underlie most arguments in favor of a government that does more than enforce the rules of justice, a government that also promotes social virtues through education, vice laws, and so forth. Such arguments are known to every libertarian so I shall not rehearse them here. But we should understand how the traditional debates over self‐​interest have influenced this controversy. If, as Thomas Hobbes and some other philosophers maintained, self‐​interest is the sole motive of human action, then how can benevolence and other social virtues possibly arise in a free society in which the pursuit of self‐​interest is unfettered by laws that restrain immorality? What is the origin of our social passions, and to what extent can those passions hold our purely selfish inclinations in check? Why should we care about others unless their welfare is connected to our personal interests? Given human nature, is authentic benevolence even possible? If our natural disposition is to treat other people as means to our ends rather than ends in themselves, then how can a free and spontaneous social order possibly sustain itself?

These and similar questions have occupied the attention of classical liberal philosophers for centuries. Indeed, entire books, such as Smith’s The Theory of Moral Sentiments, were written to explain how the voluntary social virtues will arise in a free society, and how rational self‐​interest will actually strengthen the bonds of social order. Classical liberals tended to agree with John Milton (The Second Defence of the English People, 1654) that “liberty is the best school of virtue, and affords the strongest encouragement to the practice.” Virtue cannot be coercively imposed, nor can it be acquired by eliminating all possible sources of vice. As Milton wrote in Areopagitica (1644):

[W]hat wisdom can there be to choose, what continence to forbear, without the knowledge of evil? He that can apprehend and consider vice with all her baits and seeming pleasures, and yet abstain, and yet distinguish, and yet prefer that which is truly better, he is the true warfaring Christian. I cannot praise a fugitive and cloistered virtue unexercised and unbreathed, that never sallies out and sees her adversary, but slinks out of the race, where that immoral garland is to be run for, not without dust and heat. Assuredly we bring not innocence into the world, we bring impurity much rather; that which purifies us is trial, and trial is by what is contrary. That virtue therefore which is but a youngling in the contemplation of evil, and knows not the utmost that vice promises to her followers, and rejects it, is but a blank virtue….