We insisted that the effectiveness of the Congress showed itself in two other directions still: on the one side, there was at last a congress with a unified programme, a congress which stood for a definite thought, and which brought all its efforts to bear on the solution of one problem. There seemed a far-reaching agreement of opinion that this new principle of congress administration had successfully withstood the test of practical realization. Mere conglomerations of unconnected meetings with casual programmes and unrelated papers cannot claim any longer to represent the only possible form of international gatherings of scholars. More than that, their superfluous and disheartening character will be felt in future more strongly than before. No congress will appear fully justified whose printed proceedings do not show a real plan in its programme. And the consciousness of this mission of the Congress will certainly be again reinforced by the publication of these volumes, inasmuch as it is evident that they represent a substantial contribution to the knowledge of our time which would not have been made without the special stimulating occasion of the Congress. And, finally, whether such a congress is held again or not, the impulse of this one cannot be lost on account of the special end to which all its efforts have been directed: the unity of scientific knowledge. We had emphasized from the first that here was the centre of our purposes in a time whose scientific specialization necessarily involves a scattering of scholarly work and which yet in its deepest meaning strives for a new synthesis, for a new unity, which is to give to all this scattered labor a real dignity and significance; truly nothing was more needed than an intense accentuation of the internal harmony of all human knowledge. But for that it is not enough that the masses feel instinctively the deep need of such unifying movements, nor is it enough that the philosophers point with logical arguments towards the new synthesis. The philosopher can only stand by and point the way; the specialists themselves must go the way. And here at last they have done so. Leaders of thought have interrupted their specialistic work and have left their detailed inquiries to seek the fundamental conceptions and methods and principles which bind all knowledge together, and thus to work towards that unity from which all special work derives its meaning. Whether or not their coöperation has produced anything which is final is a question almost insignificant compared with the fundamental fact that they coöperated at all for this ideal synthetic purpose. This fact can never lose its influence on the scholarly effort of our age, and will certainly find its strongest reinforcement in this unified publication. It has fulfilled its noblest purpose if it adds strength to the deepest movement of our time, the movement towards unity of meaning in the