But if the contrast between his real intention and his social technical successes may not appear striking to the physicist or chemist, it would appear at least embarrassing to the scholars in many other departments and directly bewildering to not a few. Perhaps two thirds of the sciences to which the best thinkers of our time are faithfully devoted would then be grouped together and relegated to a distant corner, their only practical technical function would be to contribute material to the education of the cultured man. For what else do we study Sanscrit or medieval history or epistemology? And finally even the uniform topic of practical use would not have brought the different sciences nearer to each other; the Congress would still have remained a budget of disconnected records of scholarship. If the practical side of the Exposition was to suggest anything, it should then not be more than an appeal not to overlook the importance of the applied sciences which too often play the rôle of a mere appendix to the system of knowledge. The logical one-sidedness which considers practical needs as below the dignity of pure science was indeed to be excluded, but to choose practical service as the one controlling topic would be far more anti-scientific. 2. _The Unity of Knowledge_ There was another side of the Exposition plan which suggested a stronger topic. The World's Fair was not only an historical memorial work, and was not only a show of the practical tools of technical civilization; its deepest aim was after all the effort to bring the energies of our time into inner relation. The peoples of the whole globe, separated by oceans and mountains, by language and custom, by politics and prejudice, were here to come in contact and to be brought into correlation by better mutual understanding of the best features of their respective cultures. The various industries and arts, the most antagonistic efforts of commerce and production, separated by the rivalry of the market and by the diversity of economic interests were here to be brought together in harmony, were to be correlated for the eye of the spectator. It was a near-lying thought to choose correlation as the controlling thought of a scientific World's Congress too. That was the topic which was finally agreed upon: the inner relation of the sciences of our day.