The Philosophy of Positive Law: Foundations of Jurisprudence

The Philosophy of Positive Law: Foundations of Jurisprudence

by James Bernard Murphy

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In this first book-length study of positive law, James Bernard Murphy rewrites central chapters in the history of jurisprudence by uncovering a fundamental continuity among four great legal philosophers: Plato, Thomas Aquinas, Thomas Hobbes, and John Austin. In their theories of positive law, Murphy argues, these thinkers represent successive chapters in a single… See more details below


In this first book-length study of positive law, James Bernard Murphy rewrites central chapters in the history of jurisprudence by uncovering a fundamental continuity among four great legal philosophers: Plato, Thomas Aquinas, Thomas Hobbes, and John Austin. In their theories of positive law, Murphy argues, these thinkers represent successive chapters in a single fascinating story. That story revolves around a fundamental ambiguity: is law positive because it is deliberately imposed (as opposed to customary law) or because it lacks moral necessity (as opposed to natural law)? These two senses of positive law are not coextensive yet the discourse of positive law oscillates unstably between them. What, then, is the relation between being deliberately imposed and lacking moral necessity? Murphy demonstrates how the discourse of positive law incorporates both normative and descriptive dimensions of law, and he discusses the relation of positive law not only to jurisprudence but also to the philosophy of language, ethics, theories of social order, and biblical law.

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Editorial Reviews

Charles J. Reid
"Original and persuasive. . . . Murphy makes the important historical point that we must look much deeper in the history of western legal theory to understand how positive law acquired its deep incoherence."—Charles J. Reid, University of St. Thomas, Minnesota

Frederick Schauer
"An important and successful effort to trace the concept of positive law in both the natural law and legal positivist traditions, this book is an extraordinarily impressive integration of classical philosophy, political theory, legal history, and jurisprudence."—Frederick Schauer, Harvard University

James Gordley
"Murphy's erudite and beautifully written study not only meticulously investigates the subtleties of a fundamental concept—positive law—but shows that without understanding them one will misinterpret some key figures in intellectual history."—James Gordley, School of Law, University of California at Berkeley

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The Philosophy of Positive Law

Foundations of Jurisprudence
By James Bernard Murphy

Yale University Press

Copyright © 2005 Yale University
All right reserved.

ISBN: 978-0-300-10788-3

Chapter One

Positive Language and Positive Law in Plato's Cratylus


The English expression positive law is by origin a direct translation of a variety of Latin expressions, such as ius positivum and lex positiva; these Latin expressions, however, do not have their origin as translations or even paraphrases of any Greek expressions. Instead, as Kuttner and others have shown, these Latin expressions for "positive" law find their origin in Greek debates about whether language is natural (phusei) or positive (thesei). The source of the new discourse of "positive" law and justice among the theologians and canonists of the twelfth-century cathedral school of Chartres seems to have been the rediscovery of Chalcidius's ancient commentary on Plato's Timaeus, in which Chalcidius speaks of "positive justice." Chalcidius himself in the fourth century likely drew the term positiva from Aulus Gellius, who used it in the second century to render Greek debates about language. Gellius tells us that the Roman Pythagorean philosopher and friend of Cicero, P. Nigidius Figulus, "taughtmost shrewdly that names are not positive, but natural."

My concern, however, is not lexical but philosophical. I am interested not in the origin and history of the Greek, Latin, and modern terms for positive law but rather in the concepts expressed by those terms. As we have observed, the first sense of "positive" is a descriptive thesis about the origins or source of a word or of a law: a positive word or law is one whose meaning or content was deliberately imposed. The second sense of "positive" is a normative thesis about the meaning of a word or the content of a law: a positive word lacks an intrinsic connection to its meaning just as a positive law lacks an intrinsic connection to morality. One cannot "see" the meaning of the word green in the word itself, nor does "green" sound green; its relation to the concept of green is purely contingent. Similarly, one cannot "see" the justice of paying a tax at 33.65 percent; that requirement has only a contingent relation to justice. By contrast, onomatopoetic words are said to have a natural relation to what they mean, while "you shall not kill" is said to have a natural relation to justice.

The first sense of "positive" is a descriptive thesis about the origin of a word or of a law: here the implicit contrast is usually with what is customary. The second sense of "positive" is a normative thesis about the content of a word or of a law: there the implicit contrast is with what is natural. Why is the word positive used to pick out both of these quite different conceptual contrasts? Perhaps because of the assumption that a sound can have a merely contingent or arbitrary relation to what it signifies or a law can have a merely contingent relation to morality only by deliberate imposition. Since the word does not have intrinsic meaning and the law has no intrinsic moral force, each must acquire that meaning or force by deliberate decision. Conversely, a word with an intrinsic relation to its meaning, such as "bang!", or a law with an intrinsic relation to morality, is often supposed to have no need of deliberate imposition. However, these inferences would be false: natural words and laws can (also) be deliberately imposed, just as contingent words and laws can arise from custom without deliberate imposition. So the two senses of positive law, while undeniably related, are far from coextensive. From the normative thesis about the content of a word or of a law we cannot infer a particular descriptive thesis about its origin, nor from a descriptive thesis about origins can we infer a particular normative thesis.

This conceptual conflation is not peculiar to English. A semantic analysis of the Latin terms for "positive" law (based on variants of pono: legem ponere, lex posita, lex positiva, ius positivum) as well as its Greek prototypes (variants of tithemi: thesis, keitai, thetikos, thesmos) and modern European progeny (positive, positif, positiv) reveals a striking continuity from Greek antiquity to contemporary usage: in each language one word yokes together two quite different concepts.


The historians of "positive law" merely point to the ancient Greek debates about language as the lexical source of the discourse of positive law. Because they have not unpacked the conceptual complexity of "positive" law, they do not see how the Greek debates about language give rise not just to the terms but also, and more important, to the concepts and confusions of the whole discourse of law's positivity. Indeed, when we widen our horizons from the lexical to the conceptual, we shall discover that we cannot understand this newer discourse about what is natural (phusei) and what is positive (thesei) until we grasp how and why it grew out of the older discourse about what is by nature (phusei) and what is by convention (nomoi). The transformation of what is "conventional" into what is "positive" has profound significance for debates about language and about law across many thinkers and over many centuries; here we must restrict ourselves to a few pertinent observations.

The discovery of the contingent and the accidental is one of the latest and least welcome of human insights. We much prefer to think of our words and of our rules as grounded in nature or at least in tradition: thus, in coining new words we rarely invent new sounds, and our purely conventional measures, such as a meter or a yard, pretend to be based on natural dimensions. The claim that many of our beliefs, practices, customs, and laws are not natural but conventional emerged originally from ancient Greek reflection upon language. As Felix Heinimann shows in detail in his classic study Nomos und Physis, the contrast of what is merely conventional to what is natural grew out of earlier contrasts in Greek thought between what is merely verbal and what is actually real. In every archaic society, language is thought to have, under certain circumstances, an intrinsic and even a causal relation to reality; this is the basis of magical incantations, in which speech and reality, word and deed are inseparable. The philosophy of language begins with a reflection upon the contrast of word and deed. Homer emphasizes the heroic ideal of the unity of word and deed in the Iliad against the backdrop of awareness that they often diverge; and Odysseus became the compelling exemplar precisely of the possible contradiction between word and deed. Gradually, "mere" words or, as we still say, "mere rhetoric" became devalued in favor of "real" deeds. Over time these literary contrasts of word to deed (epos, glotta, logos to ergon, pragma) developed into philosophical contrasts of word to reality (onoma to pragma, ergon, ontos), of mere opinion to truth (doxa to aletheia). Even in the heyday of the Sophistic contrast of what is by nature (phusei) and what is by convention (nomoi), Euripides would still invoke the older contrast: "They were friends in speech, but not in deeds."

Several early Greek philosophers of nature reflected upon the chasm between what is said about the world and what is really true of it. Parmenides strongly contrasts the language of change with the reality of changelessness; our language of "coming into" and "passing out of" being and generally of change reflects only our beliefs, not reality. Similarly, Empedocles says that the mingling and exchange of elements involves no birth or death; but he admits that even he cannot avoid speaking of the combination and dissolution of these elements as a coming-into-being and a passing-out-of-being. By speaking of birth and death "they do not call them [the elements] what is just [to call them]; even I must say them with custom [nomoi]." Here language is identified with mere opinion in contrast to the essential nature of reality. Democritus was famous for contrasting our merely subjective common speech to what is objectively real: by convention (nomoi), he says, there is sweet, bitter, hot, cold, and color; but in reality (eteei), only atoms and the void.

Recall that in one sense "positive" means contingent or accidental, as opposed to what is required by reason or nature. In the above passages, words are described as "positive" or conventional (nomoi) in this sense, as opposed to the reality of nature. However, "positive" can also mean what is deliberately "imposed or posited," in contrast to what spontaneously grows up by nature or custom. Because the Greek word for convention (nomos) could refer to either custom or statute, when Greek writers wished to emphasize the imposition of positive law, they would usually modify nomos with some variant of the verb to impose or to set down (tithemi). If "positive" language and law is what is deliberately imposed, then we see the emergence of the discourse of "positive" language and of "positive" law in the same passage. The standard term employed by Plato, Aristotle, and others for a legislative enactment (nomothetema) has its first attested use in describing words as "posited." Here (De arte 2), the Hippocratic writer says that names follow from the forms of things, "for it would be illogical and impossible for the forms [eidea] to have grown from the names, for names are legislative impositions on nature [nomothetemata (phuseos)], whereas forms are not legislative impositions, but natural growths." In this passage, names are said to be positive not because they are adventitious but because they are impositions on nature, rather than growths from nature. This is a descriptive thesis about the origin of names and the origin of natural forms: names are deliberate impositions, while natural forms are spontaneous growths.

Even the terms natural and conventional, then and now, mix normative and descriptive meanings. We often use "natural" to refer both to the spontaneous origin of something and to its essence. Similarly, Greek philosophers frequently used the term nature (phusis) to mean both the origin of a substance and its essence. In the passages cited above, Empedocles uses phusis to mean "birth," while the Hippocratic writer says that the forms are natural growths. In perhaps the first use of the nature/convention contrast in an ethical context, Archelaus, the teacher of Socrates, said that "living things first emerged from slime and that what is just and what is shameful are not by nature but by convention." Here the claim seems to be a descriptive one: what is just did not emerge spontaneously in human evolution (as living things emerged from slime) but was deliberately invented. At the same time, of course, "nature" also means, especially when contrasted with "convention," what is permanent, real, and essential. Scholars have long debated whether phusis primarily refers to the origin (genesis) of things or to their essence (ousia). But Aristotle tells us that nature means both, and that the two meanings are related, because "nature in the sense of origin is [oriented] toward nature [in the sense of essence]." Greek philosophical thought about nature did not sharply distinguish empirical questions about the origins of things from normative and metaphysical questions about their essences.

In the case of what is "conventional" we find a similar set of contrasting meanings: to describe something as "conventional" can mean that it arose not spontaneously but by human artifice, either tacitly, through custom, or deliberately, through enactment; at the same time, one can use "conventional" as a term of normative appraisal, as when it means "merely believed, adventitious, or illusory"-what John Kenneth Galbraith calls "the conventional wisdom." For example, Socrates's disciple, Antisthenes, famously said that "according to convention there are many gods but according to nature only one." What is merely said or believed (nomizetai) is contrasted with what is actually real and true (phusei kai eteei). We have already seen how Parmenides, Empedocles, and Democritus denigrate what is merely conventional as illusory, subjective, and false; but the normative appraisal of convention need not be negative: Protagoras, among others, champions convention as our artful escape from the misery of the state of nature. Where nature is described as primitive and "red in tooth and claw," convention becomes valued as the basis of security, peace, the arts, and sciences. Yet so great was the normative prestige of nature that even champions of convention resorted to appeals to it. One writer observes that, by nature, human beings are individually vulnerable and insecure in a state of nature, so that "by reason of these necessities law and the just were enthroned among men-and by no means to be overthrown, for by nature these things are strongly embedded." Here the argument is that although conventions are artificial, they are not arbitrary, reflecting instead the necessities of natural survival. The author clearly wants to associate human conventions with the necessity, objectivity, and reality usually associated with nature.

Finally, the whole messy mixture of normative and descriptive theses at stake in the discourse of nature and convention is best revealed in the fragment of Antiphon, who notoriously counsels us to obey conventional laws only when we fear getting caught; otherwise, he says, we should follow the precepts of nature: "For the affairs of law are arbitrarily imposed [epitithemi], while the affairs of nature are necessary; and the affairs of law are agreements, not natural growths, while the affairs of nature are natural growths, not agreements." Antiphon not only describes how natural growths differ from artificial impositions; he also prescribes following nature, not convention, because nature is necessary, true, and real. Moreover, Antiphon's conception of convention is "positivistic" in the sense that he sees conventions as deliberately "imposed" (thesei) rather than the tacit growth of custom.


The full significance of the transformation of the older discourse about what is natural or conventional into the new discourse of positivity is evident only when we turn to Plato. Plato's dialogue Cratylus has a uniquely pivotal role in the history of philosophical reflection upon language. No doubt Proclus, in his fifth-century commentary, oversimplifies when he says that "Pythagoras and Epicurus take the view of Cratylus while Democritus and Aristotle take the view of Hermogenes"; nonetheless, he is right that the dialogue canvasses virtually all the prior philosophical views on language, dialectically transforms the existing terms of the debates, and inspires the whole new discourse about what is natural and what is positive in the Stoic, Epicurean, Pythagorean, and Aristotelian traditions. Of special interest to us is the way in which this dialogue both exemplifies and playfully illuminates the ambiguities of the whole discourse of positivity both before and after Plato. As we have seen, the pre-Socratic debates about whether language or other institutions were by nature or by convention oscillated between two sets of concerns: first, whether the content of names or other practices reflected reality and truth or merely illusion and opinion; second, whether the origin of names and other practices is to be found in spontaneous growth (of nature or of custom) or in deliberate imposition. In the context of such a two-front war it is often difficult to know whether a defender of nature or a defender of convention is making a claim about the origin or about the content of language. Moreover, this double contrast opens the possibilities for many mixed positions, such as that language is natural in content but conventional in origin or natural in origin but conventional in content. Socrates playfully exploits this mixed position in the dialogue.


Excerpted from The Philosophy of Positive Law by James Bernard Murphy Copyright © 2005 by Yale University. Excerpted by permission.
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