Smith discusses axiology (the study of value) and David Hume’s celebrated argument about “is” and “ought.”

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.

If man is a rational animal with the ability to identify and describe facts of reality, he is also a normative animal with the ability to make value judgments. Value judgments permeate our lives. Indeed, on an average day we are likely to make many more value judgments—“ought” or “should” judgments—than purely descriptive statements of fact. Every purposeful action is driven by a value judgment, whether explicit or implicit. When we act we do so because we anticipate that the result of our action will make us better off (in some sense) than our current condition. Of course, as fallible beings our action may not generate the consequence we had anticipated. We may even conclude that our action made us worse off, in which case we may make another value judgment, “I should not have done that.”

The relationship between facts and values—between Is judgments and Ought judgments—has precipitated major controversies in moral theory, spawning a number of different schools. Many of these schools are well known, but far less known, even among some professional philosophers, are writers (mainly Austrians and Germans) in the field called axiology, a term coined in the early twentieth century. Axiology (from the Greek for “value” or “worth”) is the study of value. The basic goal of early axiologists was to develop a general theory of value that would apply to all relevant fields—including ethics, psychology, economics, history, and aesthetics. (For a good, detailed study of major philosophers of axiology, see the two‐​volume work by W.H. Werkmeister, Historical Spectrum of Value Theories, Johnson Publishing, 1970.)

Many early axiologists were Austrian and (to a lesser extent) German philosophers. Prominent names in this tradition include Franz Brentano, Alexius Meinong, Christian von Ehrenfels, and the phenomenologist Max Scheler. Also important was Heinrich Rickert, author of Science and History: A Critique of Positivist Epistemology—a book admired by F.A. Hayek (who wrote the Preface to the 1962 translation by George Reisman) and other classical liberals. According to Rickert, even purely descriptive judgments are laden with value presuppositions. But I shall postpone discussing this interesting theory until a later time.

During the early 1970s, when I read my first book on axiology, I was captivated by the enterprise. For several years thereafter I struggled to find a basis for a general theory of value that would apply to both economics and ethics, only to give up all hope. Having accepted the subjective economic theory of value defended by Mises and other Austrians, I concluded that it is impossible to apply this conception to ethics, which requires an objective theory of value. I expressed this common distinction in my first book, Atheism: The Case Against God (1974, p. 285), as follows:

We thus see that the concept of value applies to man in two different respects. First, there is the objective sense of “value,” in which things are of value to man—i.e., conducive to this welfare—whether he chooses to recognize them or not. Second, there is the subjective [sense] of “value,” in which “value” designates the result of an evaluative process; and a man’s values, in this case, represent his personal preferences. It is possible, therefore, for a man to value things (in a subjective sense) that are not in fact of value to him (in an objective sense).

This distinction goes back centuries. It was often characterized as the difference between the real (or objective) good and the apparent (or subjective) good.

David Hume on Is and Ought

In one of the most quoted, widely debated, and influential passages in the history of ethical theory, a young Scottish philosopher named David Hume wrote:

I cannot forbear adding to these reasonings an observation, which, may, perhaps, be found of some importance. In every system of morality, which I have hitherto met with, I have always remark’d, that the author proceeds for some time in the ordinary way of reasoning, and establishes the being of a God, or makes observations concerning human affairs; when of a sudden I am surpriz’d to find, that instead of the usual copulations of propositions, is and is not, I meet with no proposition that is not connected with an ought or ought not. This change is imperceptible; but is, however, of the last consequence. For as this ought, or ought not, expresses some new relation or affirmation, ‘tis necessary that is shou’d be observed and explained; and at the same time a reason should be given, for what seems altogether inconceivable, how this new relation can be a deduction from others, which are entirely different from it. But as authors do not commonly use this precaution, I shall presume to recommend it to the readers; and am persuaded, that this small attention wou’d subvert all the vulgar systems of morality, and let us see, that the distinction of vice and virtue is not founded merely on the relations of objects, nor is perceiv’d by reason. (A Treatise of Human Nature, 1739, ed. L.A. Selby‐​Bigge, 1888, reprinted by Oxford at the Clarendon Press, 1964.)

Philosophers have interpreted this passage in various ways. (For seven articles that defend and debate some of these interpretations, see Hume: A Collection of Critical Essays, ed. V.C. Chappell Anchor Books, 1966, pp. 265–334.) According to what we may call the standard interpretation, Hume was claiming that we can never “deduce” an ought from an is, or a value from a fact. Of course there is the problem of what Hume meant by “deduction.” If he used this word, as it is commonly used today, to refer strictly to the reasoning manifested in a deductive syllogism, then his argument would be true but trivial and rather uninteresting. It is obvious that the conclusion of a syllogism cannot contain anything not contained in the premises, as we see in the classic example: All men are mortal; Socrates was a man; therefore Socrates was mortal. Thus, unless a value judgment is already contained in the premises of a deductive syllogism (whether explicitly or implicitly), the conclusion cannot contain a value judgment.

Two things need to be said about this interpretation of “Hume’s Law,” as it has come to be known. First, to my knowledge no moral philosopher, not even the most “vulgar,” ever claimed to derive values from facts via syllogistic reasoning, so Hume would have been fighting a straw man if deductive syllogisms had been his target. Second, like many eighteenth‐​century philosophers, Hume sometimes used the word “deduce” in a broad sense to mean “derive.” This more general meaning of “deduce” or “deduction” is how Hume’s Law has been understood by many Humean scholars. According to this interpretation, Hume was claiming that value judgments can never be based on, or in some way derived from facts, or justified by appealing to facts about human nature, happiness, and so forth. Ought judgments are forever separated, by a logical barrier, from purely descriptive propositions, as expressed by the copula “is.”

I find this an implausible interpretation for a number of reasons. For one thing, Hume never said that value judgments cannot be based on facts. Rather, his point was that ought judgments cannot be based on reason alone. This point is evident in the final phrase of the passage quoted above: “the distinction of vice and virtue is not founded merely on the relations of objects, nor is perceiv’d by reason.” It is significant that the celebrated Is‐​Ought passage appears at the conclusion of Book III, Section 1, of the Treatise of Human Nature and seems almost an afterthought. In this section, “Moral Distinctions not deriv’d from Reason,” we find a more detailed treatment of Hume’s views than is contained in his brief, concluding remarks about “is” and “ought.” And it is simply impossible to understand what Hume was getting at in his Is‐​Ought passage without taking into account his position on the respective roles of reason and feelings (or passions or sentiments) in moral theory. Consider these comments (pp. 456–7, my italics):

Those who affirm that virtue is nothing but a conformity to reason; that there are eternal fitnesses and unfitnesses of things, which are the same to every rational being, that the immutable measures of right and wrong impose an obligation, not only on human creatures, but also on the Deity himself: All these systems concur in the opinion that morality, like truth, is discern’d merely by ideas, and by their juxta‐​position and comparison. In order, therefore, to judge of these system, we need only consider, whether it be possible, from reason alone, to distinguish betwixt moral good and evil, or whether there must concur some other principles to enable us to make that distinction.

Here Hume was clearly thinking of those moral rationalists, such as Samuel Clarke, who attempted to justify moral principles by reason alone, without taking into account the passions inherent in human nature. (For an explanation of Clarke’s theory, see my essay Self‐​Interest and Social Order in Classical Liberalism: David Hume.) These passions are the “other principles” that must be factored in if we are to understand the nature of moral judgments and actions. According to Hume, ethics is a “practical” discipline that must explain why we are motivated to care about the difference between moral and immoral behavior. But Hume’s crude conception of reason led him to conclude that reason is perfectly “inert” in matters of human action; we will not act unless we desire the outcome of an action, and our desires cannot be generated by reason alone. (Hume did attribute two important functions to reason in this area, which I shall explain in my next essay.) As Hume put it (p. 413), “reason alone can never be a motive to any action of the will.” And again (p. 457):

Since morals, therefore, have an influence on the actions and affections, it follows, that they cannot be deriv’d from reason; and that because reason alone, as we have already prov’d, can never have any such influence. Morals excite passions, and produce or prevent actions. Reason of itself is utterly impotent in this particular. The rules of morality, therefore, are not the conclusions of our reason.

It is not my intention to explain Hume’s moral theory in detail; that would take many essays and probably lose the interest of most readers. But I do wish to explore a few more points in my next essay. Before concluding this essay, however, it is important to point out that Hume’s emphasis on human passions did not cause him to embrace moral subjectivism, as that label is commonly understood. This is because Hume defended a universal conception of human nature in which every person (or almost every person) is born with the same elementary passions. This is the factual foundation of Hume’s theory of ethics—an indispensable discipline about which Hume said (p. 455): “Morality is a subject that interests us above all others. We fancy the peace of society to be at stake in every decision concerning it.” Hume, as we shall see, was a proponent of the moral sense school of ethics, and a chief purpose of this school was to ground ethics in the facts of human nature.