In the sixteenth century the State was active and doing after its kind. It was engaged in war. France was fighting Spain: England was seeking to maintain the balance: Turkey was engaged in the struggle. It is a world with which we are familiar--a world of national languages, national religions, national cultures, national wars, with the national State behind all, upholding and sustaining every form of national activity. But unity was not entirely dead. Science might still transcend the bounds of nations, and a Grotius or Descartes, a Spinoza or a Leibniz, fill the European stage. Religion, which divided, might also unite; and a common Calvinism might bind together the Magyars of Hungary and the French of Geneva, the Dutchman and the Scot. Leyden in the seventeenth century could serve, as The Hague in the twentieth century may yet serve, if in a different way, for the meeting ground of the nations; it could play the part of an international university, and provide a common centre of medical science and classical culture. But the old unity of the Middle Ages was gone--gone past recall. Between those days and the new days lay a gulf which no voice or language could carry. Much was lost that could never be recovered; and if new gold was added to the currency of the spirit, new alloys were wrought into its substance. It would be a hard thing to find an agreed standard of measurement, which should cast the balance of our gain and loss, or determine whether the new world was a better thing than the old. One will cry that the old world was the home of clericalism and obscurantism; and another will say in his bitterness that the new world is the abode of two other evil spirits--nationalism and commercialism. One thing is perhaps certain. We cannot, as far as human sight can discern, ever hope to reconstruct unity on the old basis of the Christian commonwealth of the Middle Ages. Yet need is upon us still--need urgent and importunate--to find some unity of the spirit in which we can all dwell together in peace. Some have hoped for unity in the sphere of economics, and have thought that international finance and commerce would build the foundations of an international polity. Their hopes have had to sleep, and a year of war has shown that 'a synchronized bank-rate and reacting bourses' imply no further unity. Some again may hope for unity in the field of science, and may trust that the collaboration of the nations in the building of the common house of knowledge will lead to co-operation in the building of a greater mansion for the common society of civilized mankind. But nationalism can pervert even knowledge to its own ends, turning anthropology to politics, and chemistry to war. There remains a last hope--the hope of a common ethical unity, which, as moral convictions slowly settle into law, may gradually grow concrete in a common public law of the world. Even this hope can only be modest, but it is perhaps the wisest and the surest of all our hopes.