The recondite element in learning is still, as it has been in all ages, a very attractive and effective element for the purpose of impressing, or even imposing upon, the unlearned; and the standing of the savant in the mind of the altogether unlettered is in great measure rated in terms of intimacy with the occult forces. So, for instance, as a typical case, even so late as the middle of this century, the Norwegian peasants have instinctively formulated their sense of the superior erudition of such doctors of divinity as Luther, Malanchthon, Peder Dass, and even so late a scholar in divinity as Grundtvig, in terms of the Black Art. These, together with a very comprehensive list of minor celebrities, both living and dead, have been reputed masters in all magical arts; and a high position in the ecclesiastical personnel has carried with it, in the apprehension of these good people, an implication of profound familiarity with magical practice and the occult sciences. There is a parallel fact nearer home, similarly going to show the close relationship, in popular apprehension, between erudition and the unknowable; and it will at the same time serve to illustrate, in somewhat coarse outline, the bent which leisure-class life gives to the cognitive interest. While the belief is by no means confined to the leisure class, that class today comprises a disproportionately large number of believers in occult sciences of all kinds and shades. By those whose habits of thought are not shaped by contact with modern industry, the knowledge of the unknowable is still felt to the ultimate if not the only true knowledge. Learning, then, set out by being in some sense a by-product of the priestly vicarious leisure class; and, at least until a recent date, the higher learning has since remained in some sense a by-product or by-occupation of the priestly classes. As the body of systematized knowledge increased, there presently arose a distinction, traceable very far back in the history of education, between esoteric and exoteric knowledge, the former--so far as there is a substantial difference between the two--comprising such knowledge as is primarily of no economic or industrial effect, and the latter comprising chiefly knowledge of industrial processes and of natural phenomena which were habitually turned to account for the material purposes of life. This line of demarcation has in time become, at least in popular apprehension, the normal line between the higher learning and the lower.