The essential elements of this artificial notion regarding customary law came from two sources. In part they were furnished by the canon law.7 The Church's system, at the moment when its principal lines of development had ceased, was dominated by a desire to establish firmly the principle of authority and to assure uniformity of constitution and discipline within the Church. Canon law was little apt to look with favor upon custom, which is the natural stronghold of particularism; and yet it tolerated custom as an inevitable phenomenon, merely endeavoring to limit its production as much as possible.8 In part also this artificial notion was derived from the compilations of Justinian, which were written during a period of blind faith in the omnipotence of legislation.9 These two elements were combined and fused by the post-glossators,10 canonists, and civilians, who for centuries worked to realize the substitution of the Roman law, more or less modified through interpretation, for local usage and the rules originating through custom. In the spread of the Roman and ecclesiastical conception of custom, which tended to reduce this source of law to very feeble productivity, they saw, and rightly, one of the most effective means of realizing their aim.
7 The compilations forming the Corpus Juris Canonici contain references of considerable length to the general theory of the source of law and the function of custom. The provisions relating to custom are gathered together in Gratian's Decree, Distinctions 1 to 15, part i (especially 8, 11, 12); in the other parts of the Corpus Juris we find them more or less scattered (though a few parts contain Titles: "De consuetudine"). Cf. the enumeration and analysis of these provisions in Brie, "Die Lehre vom Gewohnheitsrecht," vol. i, pp. 59-95, Sec. Sec. 9-12.
8 Upon the spirit of the canon law, cf. Gierke, "Deutsches Privat-recht," vol. i, Sec. 20, ii, p. 160; and "Genossenschaftsrecht," vol. iii, p. 307, note 185; Puchta, "Gewohnheitsrecht," i, p. 184; Brie, loc. cit., p. 63.
The Roman and canonical origins of this conception of custom would justify (were it possible to regard it as correct), the contrast frequently emphasized between legislative law as the product of the will and of reflection, and custom as the work of mere juridical instinct. This conflict represents custom as due exclusively to the spontaneous and unreasoned effort of individuals, combined with the inevitable action of the laws of imitation.11 According to this doctrine, we may speak (with Geny) of the "unconscious and blind force of custom." And we would have to recognize that the branch of legal science whose function we desire to define (that is, "legal policy") could play no part in directing these natural and unconscious movements from which custom springs; and that it is powerless, therefore, to produce any effect outside of legislation.12
9 This faith is especially evident in the famous Constitutions prohibiting any private commentary and reserving to the Emperor the function of interpreting the doubts to which his legislation might give rise: Cod. I, 17, 1, 2, "C. de veteri jure enucleando . . . etc." Cf. Geny, "Methode d'interpretation et sources en droit prive positif" (1900), p. 73.
10 Brie, loc. cit., pp. 95-128, contains an interesting analysis of the theories of the glossators on this matter; of the post-glossators, pp. 128-164; and of the canonists, pp. 165-202.
11Upon the function of imitation (which tends somewhat to limit the character of the spontaneity of custom) as understood by students of the Pandects, cf. Tarde, "Les Transformations du droit" (1893), p. 204, "Les Lois de l'imitation" (2d ed. 1895), pp. 267 seq.; and from the exclusively philosophical point of view, cf. Geny, "Methode d'interpre-tation et sources en droit prive positif," p. 299; Brie, "Puissance unifi-catrice du droit contumier," contributed to the Congress of Comparative Law. 1900.