¹ Pound's Jural Postulates are familiar. Outlines of Lectures on Jurisprudence (5th ed. 1943) 168 et seq.

² The most notorious example is of course Euclidean geometry which Kant regarded as being possessed of apriori character, that is, necessarily true without regard to human experience. Even with reference to Pound's set, Stone notes with amazement that “These postulates have been regarded by a distinguished philosopher as not only stating the characteristic ideals of American civilization at the time but as having done so sub specie aeternitatis.” Province and Function of Law (1946) 367. The seventeenth century was the heyday of such eternal and immutable compilations founded on the bedrock of unchanging human reason.

³ Beginning with the Non-Aristolelian logics and the Non-Euclidean geometries. Cf. C. I. Lewis, Survey of Symbolic Logic (1918).

⁴ At the present time there are two general types of postulate sets. These may be designated in the terminology of the older philosophical systems as the formal and the material. Formal sets are used in logic, mathematics, and the physical disciplines. Material sets are best exemplified in what Dewey calls the logic of inquiry. In formal theory the endeavor is to develop a precise language to express the meaning of conventional symbols and a precise set of directions for manipulating these symbols. There was a time when it was felt to be important for these operations to distinguish axioms (or commonly and widely agreed upon conventions) from postulates (or demands for agreed-upon procedures pertinent only to the subject under investigation) and from definitions (or conventionalized meanings of terms). S. K. Langer, Introduction to Symbolic Logic (1937) 184f. These distinctions no longer have precise signification. Formal system-builders now are more interested in general formal criteria to guide their work. They concern themselves with such general notions as the consistency, the independence, and the completeness of postulates arranged in a set. A. Ambrose & Lazerowitz, Fundamentals of Symbolic Logic (1948) 145–6. Material postulate sets on the the other hand have a different purpose and take a different form. A quotation from Dewey will illustrate the point. “Inquiry in order to be inquiry in the complete sense has to satisfy certain demands that are capable of formal statement … The position here taken holds that (postulates) are intrinsically postulates of and for inquiry, being formulations of conditions, discovered in the course of inquiry itself, which further inquiries must satisfy if they are to yield warranted assertability as a consequence … The postulate is also a stipulation. To engage in inquiry is like entering into a contract. It commits the inquirer to observance of certain conditions. A stipulation is a statement of conditions that are agreed to in the conduct of some affair. The stipulations involved are at first implicit in the undertaking of inquiry. As they are formally acknowledged (formulated), they become logical forms of various degrees of generality. They make definite what is involved in a demand… (John Dewey, Logic, The Theory of Inquiry (1938) 16). It is interesting to note how Dewey uses the language of the law to explain the meaning of postulate.

⁵ Of importance to students of the law is the call for general postulate sets to express the cultural demands of modern society issued by F. S. C. Northrop in the Logic of the Sciences and the Humanities (1947). An essentially similar demand is involved in the attempt on the part of Lasswell and McDougal to formulate a Baconian inventory for principles of public policy. Lasswell and McDougal, “Legal Education and Public Policy” 52 Yale L.J. (1943) 203.

⁶ Leibniz tried it extensively in his youth. The best example is his Specimen Certitudinis seu demonstrationum in Jure exhibitum in Doctrina Conditionum (1669) in G. W. Leibniz, Sämtliche Schriften und Briefe (P.A.W. 1930) VI Series, vol. I, 369 et seq. Leibniz's philosophical confrère Wolff wrote the only comprehensive and systematic treatise on law in the axiomatic or deductive manner which ever had considerable vogue. This was the enormous work in eight volumes entitled Jus Naturae (1740–1748).

⁷ Perhaps I should say no one should take it seriously. Yet so astute a student of the law as the late Walter Wheeler Cook took great pains to show that Story's use of this terminology was unjustified. A great to-do about very little. Logical and Legal Bases of the Conflict of Laws (1942) Chap. II. Cook imposed criteria of “formal” postulate sets on what is at most a very loose set of “material” postulates or axions.

⁸ In mathematics, for example, it is customary not to argue the respective merits of alternative postulate sets. Indeed, the basic mathematical convention demands that every effort be put forth to keep a given branch of mathematics, say arithmetic, consistent, that is, that transformation formulae be developed so that passage back and forth between alternative postulate sets be orderly. Nevertheless, the struggle for consistency grows more arduous with the passage of time. In applied mathematics, for example, in mathematical statistics new mathematical techniques are developed directly in response to new problems arising in practice.

Philosophical postulates, on the other hand, generally arise in a field already thick with contending rivals, and argument on their merits is a matter of course. Churchman and Cowan, “A Discussion of Dewey and Bentley's Postulations,” 43, Jour. of Philosophy (1946) 217.

⁹ That of experimentalism. See E. A. Singer, Jr., “Philosophy of Experiment,” Symposium, vol. 1, no. 2 (1930); H. B. Smith, Postulates of Empirical Thought, in Philosophical Essays in Honor of Edgar Arthur Singer, Jr. (1942) 24; E. A. Singer, Jr., Mind as Behavior (1924); C. W. Churchman, Theory of Experimental Inference (1948).

¹⁰ The writer has developed this topic in “Legal Pragmatism and Beyond,” in Interpretations of Modern Legal Philosophies (Essays in Honor of Roscoe Pound) (1947) 130; and in “The Historian and the Philosophy of Science,” 38 Isis, (1947) I-II, 11.

¹¹ On the question of what is happening to the historic relation between jurisprudence on the one hand and science and philosophy on the other see Huntington Cairns, “Philosophy as Jurisprudence” in Interpretations of Modern Legal Philosophies (1947) 52.

¹² C. W. Churchman argues these matters at length in Theory of Experimental Inference (1948) especially in Chaps. X to XIII.

¹³ The right of the chancellor to “experiment” with the operation of the decree illustrates the point. H. L. McClintock, Handbook of the Principles of Equity (2d ed., 1948) 32.

¹⁴ Hans Kelsen, Society and Nature (1943). On the point generally see Werner Jaeger, Paideia, The Ideals of Greek Culture (1939–44).

¹⁵ The theoretical resolution of the paradox of mechanism and purpose is worked out with exactness by E. A. Singer, Jr. in “Logico-Historical Study of Mechanism,” in Studies in the History of Science, Univ. of Penn. Bicentennial Conference (1941).

¹⁶ For the sake of convenience reference to the various schools of jurisprudence will where possible be to Pound's Outlines of Lectures on Jurisprudence (5th ed. 1943) and to Julius Stone's Province and Function of Law (1946). For example, on the subject of mechanical jurisprudence see Pound's Outlines 26, 29.

¹⁷ Outlines, 94–114.

¹⁸ The realist's pre-occupation with the “unique case” illustrates the difficulty of insisting that the purpose of every legal event be considered to the exclusion of its proper place in an orderly system of legal relations. The term unique case is itself paradoxical. For if a case is truly unique, no one can say what it is a “case of.” On this subject generally see my article on “Legal Pragmatism and Beyond”, in Interpretations of Modern Legal Philosophies 137–8. “Hegel showed that the unique case is unique only in the absence of thought. Reflection turns it immediately into a universal.”

¹⁹ Again, for an extension of this brief historical sketch see “Legal Pragmatism and Beyond” and “The Historian and the Philosophy of Science.”

²⁰ Jerome Frank, Law and the Modern Mind (1930).

²¹ Stammler's and Kelsen's in particular. See Pound's Outlines 16–19; Stone 317–327; 91 et seq.

²² Once more especially Kelsen's. Stone 93–96.

²³ Analytical jurisprudence, that is, at least to the extent that it regards existing authoritative legal materials as sufficient for a complete system of jurisprudence.

²⁴ Professor Karl Olivecrona to the contrary notwithstanding. See his article “Law as Fact,” in Interpretations, 542.

²⁵ The idealistic philosophies.

²⁶ Stammler and Kantians generally. (See Stone 317–320).

²⁷ Stone on Kohler, 40.

²⁸ Pound's Outlines, 20.

²⁹ See the writer's “Critique of the Moralistic Conception of Criminal Law,” 97 Univ. of Pa. L. R. (1949) 502.

³⁰ This postulate is especially sympathetic to the so-called clinical theory of legal teaching. The clinic and the laboratory, experience and experiment, are very closely related. The dispute between the “clinic” and the “laboratory” now being furiously waged by partisans in psychology is after all a family fight. Neither clinic nor laboratory can afford to refuse to close ranks before the onslaughts of an anti-scientific attack. For the best example of the clinical approach to law see Judge Frank's recent writings, particularly “A Plea for Lawyer-Schools,” 56 Yale L. J. (1947) 1303; “Say It With Music,” 61 Harv. L. R. (1948) 921; “Cardozo and the Upper-Court Myth,” 13 Law and Contemp. Problems (1948) 369.

³¹ For an extended discussion of the methods of science here referred to see C. W. Churchman, Theory of Experimental Inference (1948) 90 f.

³² W. A. Shewhart, Statistical Method from the Viewpoint of Quality Control (1939).