¹ Digest, 1, 3, 31; cf. John of Salisbury, Policraticus, Bk. 4, Ch. 2; Aquinas, Summa Theologiae, Ia I Iae, q. 96, a. 5.

² Many of these ideas were suggested by John of Salisbury, from whose Policraticus, Bk. 5, Ch. 6, the quoted phrase is taken; in the thirteenth century, they are explicit in, e.g., Bracton, Aquinas, or Aegidius Romanus: see McIlwain, C. H., The Growth of Political Thought in the West (New York, 1932), pp. 320–33, 373–82Google Scholar, and Constitutionalism Ancient and Modern (Ithaca, 1940), Ch. 4Google Scholar; Lewis, Ewart, Medieval Political Ideas (London and New York, 1954), Vol. 1, pp. 244–54Google Scholar; their medieval formulation owed much to the study of Roman law: see, e.g., Schulz, Fritz, “Bracton on Kingship,” English Historical Review, Vol. 60, pp. 136–77 (May, 1945)CrossRefGoogle Scholar.

³ E. g., Aquinas, op. cit., q. 97.

⁴ Note the relation between ruler and positive law, ibid., qs. 90–97, passim; in Aegidius Romanus, De Regimine Principum, Bk. 3, Pt. 2, Chs. 12, 29; cf. Lewis, op. cit., Vol. 1, pp. 20–23; for the thirteenth-century civilists, see Carlyle, R. W. and Carlyle, A. J., A History of Mediaeval Political Theory in the West (London, 1903–1936), Vol. 2 Google Scholar, Pt. I, Ch. VII, and Post, Gaines, “The Theory of Public Law and the State in the Thirteenth Century,” Seminar, Vol. 6, pp. 42–59, at pp. 51 ff. (1948)Google Scholar. The dominant trend in medieval thought was that which insisted that the king's promulgation or changing of law should be assooiated with the consent of the weightier elements of the community, as, e.g., in Bracton, De Legibus et Consuetudinibus Angliae, intro. and Bk. 3, Ch. 9, sec. 3, and, two centuries later, in Fortescue, De Laudibus Legum Angliae, Chs. 9, 18; but the king's monopoly of legislative sovereignty was defended by one group of jurists: see Ullmann, Walter, The Medieval Idea of Law as Represented by Lucas de Penna (London, 1946), esp. pp. 48–55, 94 ff., 104 Google Scholar; Lucas himself held that the ruler might specifically derogate from natural law, but that a law intrinsically unjust or unreasonable was invalid; in the fifteenth century, Aeneas Sylvius insisted that every action of the ruler must be presumed to be just: De Ortu et Auctoritate Imperii Romani, Chs. 16–23; see also Gierke, Otto, Political Theories of the Middle Age, tr. Maitland, F. W. (Cambridge, 1927), pp. 84 ffGoogle Scholar. and notes 290, 292.

⁵ See Shepard, Max A., “Sovereignty at the Cross-Roads: A Study of Bodin,” Political Science Quarterly, Vol. 45, pp. 580 ff. (Dec., 1930)CrossRefGoogle Scholar; Ullmann, op. cit., passim, points out resemblances of Bodin's thought to that of Lucas de Penna, which he knew.

⁶ By the end of the Middle Ages, this had been reflected in the notion of mixed monarchy, which appears particularly in conciliarist thought and in Fortescue; see Shepard, , “The Political and Constitutional Theory of Sir John Fortescue,” in Essays in History and Political Theory in Honor of Charles Howard McIlwain, ed. Wittke, C. (Cambridge, Mass., 1936), pp. 289–319 Google Scholar; Lewis, op. cit., Vol. 1, pp. 271–75.

⁷ d'Entrèves, A. P., Natural Law (London, 1951)Google Scholar, Ch. II, particularly analyzes this aspect of medieval natural law as illustrated by Aquinas; I am indebted to his whole discussion of the changing meanings of natural law.

⁸ Gratian, c. 11, D. I de consecratione; used at first by canonists and civilists in the equitable interpretation of private law, this maxim was applied to public law in the thirteenth century; it might or might not be labelled a principle of natural law, but its use always implied a rational appeal to the fundamental order of justice whose self-evident cogency over-ruled more contingent principles of right.

⁹ This is clearest in Aquinas or Occam but is latent or apparent in most medieval discussions of the relations of natural law, jus gentium, and civil law, especially as focussed on questions of the legitimacy of property and servitude or of the bases of equity, the dispensing power, the emergency powers of a ruler or of a general council: see Lewis, op. cit., Vol. 1, pp. 6–15, 96–98, and “Natural Law and Expediency in Medieval Political Thought,” Ethics, Vol. 50 (Jan., 1940), pp. 144–63CrossRefGoogle Scholar; Shepard, Max A., “William of Occam and the Higher Law,” this Review, Vol. 26, pp. 1005–24 (Dec., 1932)Google Scholar, Vol. 27, pp. 24–39 (Feb., 1933); Bayley, Charles C., “Pivotal Concepts in the Political Philosophy of Ockham,” Journal of the History of Ideas, Vol. 10, pp. 199–218 (April, 1949)CrossRefGoogle Scholar.

¹⁰ Summa Theologiae, Ia IIae, q. 94.

¹¹ Codex, 5, 59, 5; on the early evolution of this maxim, see Post, , “A Romano-Canonical Maxim, ‘Quod Omnes Tangit,’ in Bracton,” Traditio, IV (1946), 197–251 Google Scholar. Here again, this rule might or might not be called a principle of natural law, but it was used as such.

¹² Canonist thought did not usually follow Aquinas's distinctions between divine and natural law but rather insisted on their ultimate identity, conceiving natural law as a sort of epitome of Christian morality, which had its fullest revelation in the Scriptures. But the canonists' sophisticated interpretation of the Scriptures in terms of a continuous and rationally systematized ethical tradition avoided many of the difficulties of this approach. When Protestantism and the printing-press had thrown open the Scriptures to miscellaneous amateur use, a continuing identification of natural and divine law bred considerable confusion, which may well have contributed to an ultimate weakening of the prestige of both. On the other hand, in proportion as rationalist natural law cut loose both from the Scriptures and from systematic philosophy, it inevitably took on a somewhat arbitrary and partisan appearance.

¹³ For examples of some explicit appeals to natural law, see Lewis, , Medieval Political Ideas, Vol. 2 Google Scholar, Index, “natural law: content of.” But it is impossible to assess the full meaning of natural law in the Middle Ages if one looks only at the instances in which natural law is specifically cited: note, e.g., the common-law concept of “reasonableness,” which, as SirPollock, Frederick pointed out in Essays in the Law (London, 1922), pp. 54–59 Google Scholar, played the same role and was part of the same system of ideas; note also the civilist approach from the concept of a basic justice which could be equated with natural reason.

¹⁴ Carlyle, op. cit., Vol. 1, Chs. I–III, Vol. 2, Chs. III, IV; Lottin, Dom Odon, Le droit naturel chez saint Thomas et ses prédécesseurs (Bruges, 1926)Google Scholar; Ullmann, , Medieval Papalism (London, 1949), Ch. IIGoogle Scholar; also references in note 10 above.

¹⁵ de Lagarde, Georges, La naissance de l'esprit laique au déclin du moyen âge, Vol. 6 (St.-Paul-Trois-Chateaux, 1946), pp. 143–58Google Scholar, argues that Occam's “natural law in the third sense” was a mere rational construct, without relation to primary natural law on the one hand or to human law on the other; but cf. Shepard, “William of Occam and the Higher Law” (cited in note 9); Scholz, Richard, Wilhelm von Ockham als politischer Denker und sein Breviloquium de principatu tyrannico (Leipzig, 1944), pp. 18–28 Google Scholar; Lewis, , Medieval Political Ideas, Vol. 1, pp. 14 ffGoogle Scholar. and notes.

¹⁶ One may suggest that Holmes' decision in Schenck v. United States (249 U. S. 47 [1919]) is, in structure and method, a neat instance of the sort of thinking that in the Middle Ages would have implied an appeal to natural law, issuing in the conclusion that natural law prescribed both the general right and the limitation upon it. The fact that the absolute prohibitions of the Bill of Rights still have a sort of natural-law aura about them, while their qualifications may seem to rest only on judicial interpretation, is an index to the shift that has occurred in the meaning of natural law. In the field of civil liberties, the practical gain may well outweigh the loss in theoretical clarity; in the case of property-rights, the balance-sheet is less clear.

¹⁷ Cf., e.g., the varying implications of freedom in Aquinas, Summa Theologiae, I, q. 96, a. 4, and De Regimine Principum, Bk. 1, Ch. 1; Tholommeo of Lucca, De Regimine Principum, Bk. 2, Chs. 8 f.; Marsiglio, Defensor Pacis, Dictio 1, Ch. 12, sec. 6; Occam, Dialogus, Pt. 3, Tr. 1, Bk. 2, Ch. 6 and Tr. 2, Bk. 2, Ch. 20; Cusa, De Concordantia Catholica, Bk. 2, Ch. 14.

¹⁸ The following section leans heavily on Gaines Post's analysis of the legal theory of taxation and consent in the articles already cited and “ Plena Potestas and Consent in Medieval Assemblies,” Traditio, Vol. 1, pp. 355–48 (1943)Google Scholar, and “The Two Laws and the Statute of York,” Speculum, Vol. 29, pp. 417–32 (April, 1954)CrossRefGoogle Scholar. The legal theory described by Post seems to me to be partly reflected and supported by theologians: e.g., Aquinas, De Regimine Judaeorum; Tholommeo, op. cit., Bk. 2, Ch. 9; John of Paris, De Potestate Regia et Papali, Ch. 7; Occam, Dialogus, Pt. 3, Tr. 2, Bk. 2, Ch. 23; cf. Bayley, op. cit.

The emphasis here is obviously a departure from the familiar emphasis, e.g., in McIlwain, , Growth of Political Thought in the West (cited in note 2), pp. 370–73, 382–85Google Scholar: that the dominant trend of medieval thought was that which set the private law as an impermeable limit to royal right and thus balanced the absolute authority of the king in government against the absolute proprietary rights of his subjects, construing grants of supply as “in the main voluntary with the subject” (p. 373) and making the whole taxation process essentially a bargain between two mutually independent centers of right. McIlwain recognizes the existence of an alternative “Romanist” tradition; evidence seems to be accumulating that the influence of “Romanist” ideas on medieval theory was both earlier and more extensive than was once supposed.

¹⁹ The nearest one conies to this seems to be in some of Marsiglio's arguments, op. cit., Dictio 1, Chs. 12, 13, for the inclusion of all classes of citizens in the legislator; but note that Marsiglio was not sufficiently concerned about the possibility of deadlock between opposing classes to provide any precise rules for the computation of votes, and that he seems to have taken for granted that the process he rather vaguely describes would result in almost unanimous consensus on “a proper and true ordination of just things”; cf. Gewirth, Alan, Marsilius of Padua (New York, 1951), Vol. 1, pp. 182 ffGoogle Scholar. The argument from the difficulty of securing agreement in a group was, of course, one of the standard arguments for kingship, but this argument typically proceeded without any allusion to class interests.

²⁰ On this phrase, see Post, “Plena Potestas and Consent in Medieval Assemblies” (cited in note 18).

²¹ Clarke, M. V., Medieval Representation and Consent (London, 1936)Google Scholar, Chs. XII, XIII, traces the role of some of these factors in thirteenth-century England.

²² Cusa, op. cit., Bk. 2, Ch. 14; Marsiglio, op. cit., Dictio 1, Ch. 12, sec. 6; Occam's strongest statement is in his Breviloquium (ed. L. Baudry), p. 121; cf. Gewirth, op. cit., pp. 219 ff.; Lagarde, op. cit., Vol. 6, pp. 183–92; Lewis, , Medieval Political Ideas, Vol. 1, pp. 26, 159–62Google Scholar, and notes.

²³ De Regimine Christiano, Pt. 2, Ch. 3.

²⁴ Op. cit., Bk. 3, preface.

²⁵ Contrast the central role of the contract in Locke with its peripheral role in, e.g., Aquinas's several discussions of the limits of political obligation (he mentions a contract only once, and then at the end of his discussion in De Regimine Principum, Bk. 1, Ch. 6); or in the analysis of the limits of obedience by the “voluntarist” Occam, Dialogus, Pt. 3, Tr. 3, Bk. 2, Chs. 20, 26–28. Altogether many medieval writers agreed in the belief that government had originated through an act of the community, and although medieval writings are sprinkled with references to Augustine's “general compact of human society to obey its kings” (Confessions, Bk. 3, Ch. 8, q. Gratian, c. 2, di. 8), discussions of the obligations of ruler and subjects could, and often did, proceed quite as well without as with any reference to this compact.

Note also the shift in the significance of the contract implied in Locke's insistence on unanimous consent compared with the medieval references to the constituent consent of “the people.”