But over and above its national significance, Jewish history, we repeat, possesses universal significance. Let us, in the first place, examine its value for science and philosophy. Inasmuch as it is pre-eminently a chronicle of ideas and spiritual movements, Jewish history affords the philosopher or psychologist material for observation of the most important and useful kind. The study of other, mostly dull chapters of universal history has led to the fixing of psychologic or sociologic theses, to the working out of comprehensive philosophic systems, to the determination of general laws. Surely it follows without far-fetched proof, that in some respects the chapter dealing with Jewish history must supply material of the most original character for such theses and philosophies. If it is true, as the last chapter set out to demonstrate, that Jewish history is distinguished by sharply marked and peculiar features, and refuses to accommodate itself to conventional forms, then its content must have an original contribution to make to philosophy. It does not admit of a doubt that the study of Jewish history would yield new propositions appertaining to the philosophy of history and the psychology of nations, hitherto overlooked by inquirers occupied with the other divisions of universal history. Inductive logic lays down a rule for ascertaining the law of a phenomenon produced by two or more contributory causes. By means of what might be called a laboratory experiment, the several causes must be disengaged from one another, and the effect of each observed by itself. Thus it becomes possible to arrive with mathematical precision at the share of each cause in the result achieved by several co-operating causes. This method of difference, as it is called, is available, however, only for a limited number of phenomena, only for phenomena in the department of the natural sciences. It is in the nature of the case that mental and spiritual phenomena, though they may be observed, cannot be artificially reproduced. Now, in one respect, Jewish history affords the advantages of an arranged experiment. The historical life of ordinary nations, such nations as are endowed with territory and are organized into a state, is a complete intermingling of the political with the spiritual element. Totally ignorant as we are of the development either would have assumed, had it been dissevered from the other, the laws governing each of the elements singly can be discovered only approximately. Jewish history, in which the two elements have for many centuries been completely disentangled from each other, presents a natural experiment, with the advantage of artificial exclusions, rendering possible the determination of the laws of spiritual phenomena with far greater scientific exactitude than the laws of phenomena that result from several similar causes.